UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2021

OR

Commission File Number 001-37345

CHINOOK THERAPEUTICS, INC.

(Exact name of Registrant as specified in its Charter)

400 Fairview Avenue North, Suite 900

Seattle, WA 98109

(Address of principal executive offices including zip code)

Registrant’s telephone number, including area code: (206) 485-7241

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☒

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company”, and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

The aggregate market value of the Registrant’s common stock held by non-affiliates as of June 30, 2021, based on the closing price of the shares of common stock on the Nasdaq Stock Market for such date, was $460,117,610.

The number of shares of Registrant’s Common Stock outstanding as of March 10, 2022 was 54,951,079.

Table of Contents

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

Corporate Information

Chinook Therapeutics, Inc. (the “Company”, “Chinook”, “we”, “our”, or “us) is a clinical-stage biopharmaceutical company. On October 5, 2020, Aduro Biotech, Inc. (“Aduro”) completed its merger with Chinook Therapeutics U.S., Inc. (“Private Chinook”), pursuant to the terms of a merger agreement dated as of June 1, 2020, and amended on August 17, 2020, by which a wholly owned subsidiary of Aduro merged with and into Private Chinook, with Private Chinook continuing as a wholly owned subsidiary of Aduro (the “Merger”). Immediately following the Merger, Aduro changed its name to “Chinook Therapeutics, Inc.” and the business conducted by Private Chinook became the primary business conducted by the Company.

Forward Looking Statements

This Annual Report on Form 10-K contains forward-looking statements about us and our industry that involve substantial risks and uncertainties. All statements, other than statements of historical facts contained in this Annual Report on Form 10-K, including statements regarding our future financial condition, business strategy and plans, and objectives of management for future operations, are forward-looking statements. In some cases you can identify these statements by forward-looking words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect” or the negative or plural of these words or similar expressions. These forward-looking statements include, but are not limited to, statements concerning the following:

These statements are only current predictions and are subject to known and unknown risks, uncertainties and other factors that may cause our or our industry’s actual results, levels of activity, performance or achievements to be materially different from those anticipated by the forward-looking statements. We discuss many of these risks in greater detail under the heading “Risk Factors” and elsewhere in this Annual Report on Form 10-K. You should not rely upon forward-looking statements as predictions of future events. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risks and uncertainties.

Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of activity, performance or achievements. Except as required by law, after the date of this report, we are under no duty to update or revise any of the forward-looking statements, whether as a result of new information, future events or otherwise.

We obtained industry, market and competitive position data in this report from our own internal estimates and research as well as from industry and general publications and research surveys and studies conducted by third parties. These data involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such information or estimates.

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PART I

Item 1. Business.

Overview

We are a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing precision medicines for kidney diseases. Our pipeline is focused on rare, severe chronic kidney diseases with well-defined clinical pathways. Our lead clinical program is atrasentan, an endothelin A receptor antagonist. In March 2021 we initiated the phase 3 ALIGN trial of atrasentan for IgA nephropathy, or IgAN, and in April 2021 we initiated the phase 2 AFFINITY basket trial for proteinuric glomerular diseases. Our second product candidate, BION-1301, is an anti-APRIL monoclonal antibody also in development for patients with IgAN. We presented results from the ongoing phase 1/2 trial at the American Society of Nephrology, or ASN, Kidney Week in November 2021. We plan to maintain commercial rights for atrasentan and BION-1301 in North America and possibly Europe. In November 2021, we also established SanReno Therapeutics, or SanReno, a joint venture to develop, manufacture and commercialize kidney disease therapies in mainland China, Hong Kong, Macau, Taiwan and Singapore, or collectively, the Territory. East-Asian populations have a higher incidence and prevalence of IgAN than in the United States and Europe. We believe that a strong local presence in East-Asia may allow us to accelerate the clinical development and maximize the commercial potential of atrasentan and BION-1301 in the region. We are also advancing our third program, CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022. We are developing CHK-336 for the treatment of primary hyperoxaluria, or PH, as well as secondary hyperoxaluria and idiopathic kidney stone formation. In addition, we are conducting research programs in several other rare, severe chronic kidney diseases. We seek to build our pipeline by leveraging insights from kidney single cell RNA sequencing, human-derived organoids and new translational models, to discover and develop therapeutic candidates with mechanisms of action targeted against key kidney disease pathways. To support these efforts, we have entered into a strategic collaboration with Evotec SE, or Evotec, to jointly identify, characterize and validate novel mechanisms and discover precision medicines for lupus nephritis, IgAN, polycystic kidney disease, or PKD, and other primary glomerular diseases. The collaboration with Evotec will also involve further characterization of pathways and patient stratification strategies for programs currently in our clinical and preclinical pipeline.

Chronic kidney disease is a large and growing problem globally, with few approved therapies and a large unmet medical need. Nearly one-in-ten people globally suffer from chronic kidney disease. In the United States alone, it is estimated that over $138 billion is spent annually on managing and treating kidney diseases, much of which is dedicated to dialysis, transplant and supportive care after a patient’s kidneys have already failed. Despite the large unmet medical need, there are few drugs approved to prevent the progression of kidney disease. Drug development in nephrology has historically been hindered by categorization of disease based on clinical presentation or kidney pathology, rather than underlying molecular mechanism or genetics. This has resulted in the development of drugs with non-specific mechanisms to address broad indications that contain heterogeneous patient populations with a variety of distinct disease drivers. Complicating matters, large, lengthy and expensive clinical outcome-based clinical trials have been required to establish proof of concept and regulatory approval for new drugs.

We believe now is an opportune time for precision medicine to be applied in kidney disease, since many of the historical barriers can be overcome. The field is rapidly changing as an increased understanding of underlying disease biology has led to new and validated drug targets, novel translational platforms, and patient stratification tools. Importantly, regulators have recently accepted biomarkers such as proteinuria and eGFR as registration endpoints in certain well-characterized disease populations, potentially reducing the time and cost previously associated with clinical trials in nephrology.

Our approach to precision medicines leverages recent advances in identifying targeted kidney therapies linked to mechanistic biomarkers by the application of systems biology approaches in nephrology. The application of systems biology to nephrology has advanced over the past decade through the study of multiple patient groups across a wide variety of kidney diseases and their associated multilevel data sets, including genome, transcriptome, proteome, metabolome, pathology and prospective long-term clinical characteristics and outcomes. A key objective of these investigations is to define kidney diseases in molecular terms to drive the development of targeted treatments. We believe we are well-positioned to exploit the insights provided into the key molecular drivers and classifiers of kidney diseases by the application of these systems biology tools to nephrology. Our strategy is to use these mechanistic insights to select compelling drug targets and deliver novel and differentiated product candidates for rare and severe kidney diseases with high unmet medical need.

Our experienced research and development team has partnered with academic founders and key opinion leaders to identify targets and utilize novel translational technologies to develop precision medicines for kidney diseases. One of the key challenges in defining molecular mechanisms of kidney disease has been the cellular heterogeneity of the kidney, with nearly 30 distinct cell types arranged in the complex three-dimensional structure of the nephron. This cellular diversity and structure have made it difficult to understand the specific mechanisms associated with loss in kidney function. The recent development of genome-wide single-cell RNA sequencing of cell populations harvested from the kidney presents a new opportunity to dissect molecular mechanisms of kidney function and disease. We utilize single-cell RNA sequencing techniques developed by one of our academic founders to gain high resolution molecular insights into kidney disease mechanisms.

The cellular heterogeneity of the kidney has historically presented barriers to developing translationally relevant in-vitro cellular models of human kidney diseases. Recently, pluripotent stem cell, or PSC, derived kidney organoids along with patient derived three-

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dimensional cellular systems have emerged as advanced preclinical models to study kidney disease. Additionally, under our collaboration with Evotec, we are utilizing Evotec’s proprietary comprehensive molecular datasets from thousands of patients across chronic kidney diseases of multiple underlying etiologies to identify, characterize and validate novel mechanisms and discover precision medicines for PKD, lupus nephritis, IgAN and other primary glomerular diseases. The collaboration will also involve further characterization of pathways and patient stratification strategies for programs currently in our clinical and preclinical pipeline.

We believe our research and discovery approach provides significant insights into human disease mechanisms and allows us to select and validate key targets that are central drivers of human kidney diseases.

Atrasentan

Our lead product candidate is atrasentan, a potent and selective endothelin A receptor antagonist that we are developing for the treatment of proteinuric glomerular diseases. In March 2021 we initiated a phase 3 trial of atrasentan called ALIGN for IgAN, and in April 2021 we initiated a phase 2 basket trial called AFFINITY for proteinuric glomerular diseases.

IgAN, the leading cause of primary glomerulonephritis, is a serious progressive autoimmune disease of the kidney with only one steroidal treatment approved. Up to 45 percent of IgAN patients progress to end-stage kidney disease, or ESKD. We estimate that IgAN affects approximately 140,000 – 150,000 people in the United States, approximately 200,000 people in Europe and several million people in Asia. Galactose-deficient immunoglobulin A1, or Gd-IgA1, is recognized as a critical autoantigen to which IgAN patients develop circulating autoantibodies, resulting in the formation and deposition of immune complexes in the glomeruli of the kidney. This process initiates an inflammatory cascade that damages the glomeruli, resulting in protein and blood leaking into the urine, called proteinuria or hematuria, respectively. Ultimately the filtration function of the kidney is impaired, reducing the ability to remove waste products from the blood. As the disease progresses, these waste products accumulate and can result in potentially life-threatening complications that often lead to the need for dialysis or kidney transplant. Sustained proteinuria is the most widely studied and the strongest predictor for the rate of progression to ESKD in IgAN.

Activation of the endothelin A receptor, or ET_A receptor, has been implicated as a key driver of proteinuria, renal cell injury, including podocyte dysfunction and mesangial cell activation, along with promoting kidney inflammation and fibrosis, all resulting in the progression of IgAN. Atrasentan, by blocking ET_A, has the potential to provide benefit in multiple chronic kidney diseases by reducing proteinuria and having direct anti-inflammatory and anti-fibrotic effects to preserve kidney function. We in-licensed atrasentan in December 2019 from AbbVie, which previously developed atrasentan for diabetic kidney disease through multiple clinical trials, including the phase 3 SONAR trial, which evaluated atrasentan in over 5,000 patients. We presented new preclinical data elucidating the mechanism of action of atrasentan in IgAN at multiple nephrology congresses in 2021, including the ISN World Congress of Nephrology, or WCN, International Podocyte Conference and ASN Kidney Week. In preclinical studies, atrasentan rapidly reduced albuminuria and downregulated intra-renal transcriptional proliferative, inflammatory and fibrotic signaling in the gddY mouse IgAN model. The data also showed that atrasentan attenuated human renal mesangial cell activation induced by endothelin-1 or IgAN patient immune-derived immune complexes in a translational model system.

In 2015, AbbVie made a strategic decision to exit kidney disease drug development and ultimately discontinued the SONAR trial in 2017 when less than half of the planned events had occurred due to a lower than predicted annual occurrence of the primary renal outcome. Clinical investigators closed the trial per protocol during which time further events accrued, and in April 2019 the data was reported at the WCN and simultaneously published in The Lancet. At that time, after only 184 out of a planned 425 events had been observed, the trial showed a statistically significant p-value of 0.029 on its primary endpoint of a composite of hard kidney outcomes, consisting of time to first occurrence of progression to end-stage kidney disease or doubling of serum creatinine. In the SONAR trial, atrasentan also demonstrated statistically significant reductions in proteinuria as well as improvements in the estimated glomerular filtration rate, or eGFR, both of which are measures of kidney function. Trial results showed atrasentan having well-characterized and manageable safety results in this high-risk diabetic kidney disease patient population. Fluid retention-related adverse events were more frequent in the atrasentan group than in the placebo group; however, these adverse events are a known class effect of endothelin receptor antagonists, and they were anticipated and generally well-managed in this high-risk diabetic population.

Based on the encouraging data from SONAR and strong mechanistic rationale, in March 2021 we initiated the phase 3 ALIGN trial of atrasentan in patients with IgAN at high risk of kidney function decline. We chose IgAN as the lead indication for evaluation of atrasentan due to the role of endothelin activation and proteinuria in disease progression, potential improved tolerability of atrasentan in this patient population, high unmet need and the possibility of submitting a new drug application, or NDA, seeking accelerated approval based on surrogate endpoints, including proteinuria. In April 2021 we initiated the phase 2 AFFINITY trial in other proteinuric glomerular diseases, including cohorts of patients with lower proteinuria IgAN, focal segmental glomerosclerosis, or FSGS, and Alport syndrome, as well as diabetic kidney disease combined with sodium glucose co-transporter 2, or SGLT2. inhibitors, such as canagliflozin or dapagliflozin, which have recently been shown to provide clinical benefit in patients with diabetic kidney disease. If our trials proceed as planned, we plan to present data from the IgAN patient cohort of the AFFINITY trial in an oral

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presentation at the ERA Congress in May 2022, and one or more additional cohorts of the AFFINITY trial during the second half of 2022, as well as data for the primary proteinuria endpoint in the ALIGN trial in 2023 to support accelerated approval.

BION-1301

We are also developing BION-1301, an investigational humanized IgG4 monoclonal antibody that blocks APRIL, a soluble factor that is believed to be implicated in IgAN and other indications, from binding to its receptors.

Patients with IgAN have significantly higher levels of APRIL than healthy individuals, and higher APRIL levels in these patients correlate with poor prognosis in the form of increased Gd-IgA1, increased proteinuria and decreased eGFR. Published literature has demonstrated that APRIL critically drives IgA class switching, the survival of IgA-producing plasma cells and the secretion of Gd-IgA1 (Hit 1 in the multi-hit pathogenesis of IgAN). Our preclinical experiments demonstrate that blocking APRIL inhibits the survival of and immunoglobulin production by human plasma cells. We have also demonstrated that IgA-producing plasma cells are more sensitive to immunomodulation by BION-1301, with a lesser effect observed on IgG, providing the potential to deplete IgA with BION-1301, while tempering effects on IgG and minimizing the potential for immunosuppression associated with IgG depletion. Blocking APRIL with BION-1301 is a distinct approach to IgAN by reducing circulating levels of Gd-IgA1 which is considered to be the pathogenic variant of IgA in IgAN. We believe BION-1301 represents a novel potential disease-modifying treatment for IgAN.

Preclinical studies have demonstrated that BION-1301 binds to a specifically defined epitope on APRIL, resulting in complete blockade of APRIL-induced receptor activation. In a preclinical study of BION-1301 in non-human primates, we observed a significant reduction of blood IgA levels and a favorable safety profile. Additional preclinical studies demonstrated that APRIL transgenic mice produce rising levels of IgA as well as IgA deposits in the kidney. Administration of mouse anti-human APRIL was shown to reduce levels of IgA in both the serum and the kidney. In patients with IgAN, BION-1301 has been shown to neutralize APRIL and deplete Gd-IgA1, resulting in clinically meaningful reductions in proteinuria.

A phase 1/2 clinical trial of BION-1301 is currently ongoing. Parts 1 and 2 of this trial evaluating the safety and tolerability of BION-1301 in healthy volunteers have been completed. In healthy volunteers, BION-1301 was well-tolerated, demonstrated dose-dependent increases in target engagement as measured by free APRIL levels, dose-dependently and durably reduced IgA, IgM and IgG levels (to a lesser extent) and had a half-life of approximately 33 days, suggesting the potential for an extended dosing interval. Additional data in healthy volunteers from this trial were presented at the 2021 WCN, or WCN’21, demonstrating BION-1301 produced dose-dependent reductions in serum Gd-IgA1 levels that were greater in magnitude than previously reported for total IgA concentrations.

In addition, we completed a phase 1 intravenous, or IV to subcutaneous, or SC, bioavailability study in healthy volunteers. Results from the bioavailability study were presented at WCN’21. In this study, BION-1301 was well-tolerated when administered by both IV and SC routes in healthy volunteers, the pharmacokinetic profile of BION-1301 was consistent with previous clinical studies, the absorption rate of BION-1301 was typical of a monoclonal antibody and the magnitude of pharmacodynamic responses were largely retained with SC dosing compared to IV dosing.

We are currently enrolling patients with IgAN in Cohort 2 of Part 3 of the phase 1/2 trial in which patients with IgAN are dosed with 600 mg of BION-1301 SC every two weeks for up to 52 weeks. We presented data from Cohort 1 of Part 3 of this trial, in which patients were dosed with 450 mg of BION-1301 IV every two weeks, at ASN Kidney Week 2021 in early November. The data presented at the conference demonstrate that BION-1301 was generally well-tolerated to date in patients with IgAN, with no serious adverse events or treatment discontinuations due to adverse events. The pharmacokinetics of BION-1301 observed in patients with IgAN were consistent with those previously reported in healthy volunteers and sufficient to drive rapid and sustained reductions in free APRIL levels, as well as durable reductions in Gd-IgA1, IgA, IgM, and to a lesser extent, IgG levels. BION-1301 demonstrated a greater than fifty percent (50%) geometric mean reduction in 24-hour urine protein creatinine ratio, or UPCR, in patients with IgAN after three (n=6) to six months (n=4) of treatment, a clinically meaningful result in this patient population.

Recent amendments to the design of Part 3 also include the option for a third cohort of patients to receive a SC dose of BION-1301 at a dose and schedule that would be determined based on data generated from Cohort 2. We believe moving forward with Cohort 3 may help us better understand the SC dose-response relationship prior to moving into a pivotal trial in IgAN, which we anticipate initiating in 2023.

CHK-336

Our third clinical development candidate is CHK-336, a liver-targeted oral small molecule lactate dehydrogenase, or LDHA, inhibitor, which we are developing for the treatment of PH, secondary hyperoxaluria and idiopathic kidney stone formation. Hyperoxalurias, including PH, are diseases caused by excess oxalate, a potentially toxic metabolite typically filtered by the kidneys

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and excreted as a waste product in urine. Symptoms of PH include recurrent kidney stones, which when left untreated, can result in kidney failure requiring dialysis or dual kidney/liver transplantation. In patients with hyperoxalurias, excess oxalate combines with calcium to form calcium oxalate crystals that deposit in the kidney, resulting in the formation of painful kidney stones and driving progressive kidney damage over time. PH1, PH2 and PH3 are a group of ultra-rare diseases caused by genetic mutations that result in excess oxalate, and in their most severe forms, can lead to end-stage kidney disease at a young age. We also believe CHK-336 may have potential in the treatment of patients with secondary hyperoxaluria and idiopathic stone formation. We have submitted an investigational new drug application, or IND, and are advancing CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022 for the treatment of PH. We have also received rare pediatric disease designation from the FDA for CHK-336 for the treatment of PH.

Research and Discovery Programs

Beyond CHK-336, we have active research and discovery efforts focused on other rare, severe kidney diseases. Our precision medicine research approach focuses on developing product candidates targeting the most promising molecular pathways identified as key disease drivers in collaboration with key scientific advisors. Our scientific advisors provide valuable guidance on target selection, prioritization and validation strategies, as well as access to technology platforms that support target validation efforts through biological insights into human disease mechanisms and translational cellular and animal model systems.

In March 2021, we announced a strategic collaboration with Evotec focused on the joint identification, characterization and validation of novel mechanisms as well as the discovery of precision medicines for lupus nephritis, IgAN, PKD and other primary glomerular diseases. The collaboration leverages access to the National Unified Renal Translational Research Enterprise, or NURTuRE, patient biobank for chronic kidney diseases and nephrotic syndrome as well as Evotec’s proprietary PanOmics platform, which combines enhanced throughput proteomics, high throughput transcriptomics and cell imaging with PanHunter, Evotec’s unique data analysis platform. Through our collaboration with Evotec, we intend to characterize molecular drivers, identify and validate novel targets and drive patient stratification strategies in kidney disease.

Our Pipeline

We have assembled a portfolio of precision medicines product candidates designed to address rare, severe chronic kidney diseases with potentially well-defined and efficient clinical pathways. We intend to further enhance our portfolio by identifying novel kidney disease targets for research and development and in-licensing promising product candidates for kidney diseases. Our development programs consist of the following:

Our Strategy

Our goal is to be a leader in the discovery, development and commercialization of precision medicines to treat kidney diseases. Our strategy includes the following key components:

Continue to advance the phase 3 ALIGN trial of atrasentan for IgAN towards an expected topline proteinuria data readout in 2023, and begin presenting data from the phase 2 AFFINITY basket trial for proteinuric glomerular diseases during 2022. In March 2021, we initiated the phase 3 ALIGN trial of our lead product candidate, atrasentan, for IgAN. We received feedback from the U.S. Food and Drug Administration, or the FDA, and the European Medicines Agency, or the EMA, on the design of our phase 3 trial, which utilizes reduction in proteinuria after six months of treatment as the primary endpoint to support an application for accelerated approval under Subpart H in the United States, and reduction in eGFR decline following 2.5 years of treatment followed by a wash-

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out period as the potential confirmatory endpoint for full approval, if accelerated approval is granted. In April 2021 we initiated the phase 2 AFFINITY basket trial in proteinuric glomerular diseases. We plan to present data from the IgAN patient cohort of the AFFINITY trial in an oral presentation at the ERA Congress in May 2022, and one or more additional cohorts of the AFFINITY trial during the second half of 2022, followed by topline proteinuria data from ALIGN expected in 2023. We believe the hemodynamic, anti-fibrotic and anti-inflammatory properties of atrasentan, as well as its impact to reduce mesangial cell activation, could provide significant clinical benefit on top of standard-of-care RASis for patients with IgAN.

Determine the optimal dose and schedule for BION-1301 to advance into a pivotal trial for IgAN in 2023. We plan to complete Part 3 of the ongoing phase 1/2 clinical trial in which patients with IgAN receive subcutaneous BION-1301 during 2022. Data from Part 3 of this trial is intended to confirm the SC dose-response relationship of BION-1301 and inform the design of a pivotal trial in IgAN, which we anticipate initiating in 2023. We believe the mechanism of action of BION-1301 could potentially be disease-modifying for patients with IgAN.

Advance CHK-336 into a phase 1 trial in healthy volunteers during 2022 to position the program for a proof-of-concept trial in hyperoxaluria patients in 2023. We are advancing CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022 for the treatment of PH. We believe CHK-336 could represent an important new treatment option for patients with diseases caused by excess oxalate production.

Identify and validate novel targets and utilize translational platforms to develop a pipeline of product candidates for rare, severe chronic kidney diseases. Our chemistry and biology teams have partnered with our academic founders and key opinion leaders, to identify, validate and develop precision medicines to add to our preclinical pipeline. Our lead program from these internal research efforts is CHK-336 for hyperoxalurias, and we also have multiple active research programs underway in other rare, severe chronic kidney diseases. Our collaboration with Evotec will supplement our internal efforts to define the molecular drivers of kidney diseases, identify novel targets for drug development in selected patient sub-populations and continue to build the foundation for our precision medicine approach.

Enhance our product portfolio by identifying novel disease targets and in-licensing promising product candidates for kidney diseases. We are actively evaluating and pursuing novel targets, intellectual property and product candidates for acquisition and in-licensing to supplement our internal research efforts and continue to build our pipeline of precision medicines for kidney disease. Through our team’s focus and expertise in kidney disease, as well as our connections within the nephrology community, we are positioning the company as a partner of choice for promising renal programs. We believe continued advances in the biological understanding of kidney diseases will provide opportunities to further expand our portfolio with preclinical and/or clinical product candidates.

Maintain broad commercial rights to our product candidates. We plan to maintain commercial rights for atrasentan and BION-1301 in North America and possibly Europe. In November 2021, we also established SanReno Therapeutics, a joint venture in China to develop, manufacture and commercialize kidney disease therapies in mainland China, Hong Kong, Macau, Taiwan and Singapore. There is a large unmet medical need due to the higher incidence and prevalence of IgAN among east-Asian populations, and we believe it is important to have a strong local presence that may allow us to accelerate the clinical development and maximize the commercial potential of atrasentan and BION-1301 in the region. As we continue to advance our programs, we may pursue additional strategic collaborations to share risk and supplement our resources at the appropriate time, especially in regions outside of North America.

Continue to strengthen and expand our intellectual property portfolio. We have an intellectual property portfolio that includes issued and pending claims for atrasentan and BION-1301, as well as pending claims relating to CHK-336, in the United States and other countries. We will also look to in-license any third-party patents relating to our pipeline programs as needed. Our proprietary position is reinforced by additional technical know-how and trade secrets. We continually assess and refine our intellectual property strategy and will file additional patent applications as appropriate.

Chronic Kidney Disease Background

Chronic kidney disease, or CKD, is a large and growing problem globally. In 2017, the global prevalence of CKD was 9.4 percent (697.3 million cases) and CKD has risen from the 29th leading cause of global disability-adjusted life-years, or DALYs, in 1990 for all ages to the 18th in 2019. Overall, nearly one in ten people around the world have CKD. In the United States alone, the health care system spends over $120 billion annually on kidney disease, much of which is dedicated to dialysis and transplant after a patient’s kidneys have already failed. There have been few new drugs developed and approved for chronic kidney diseases over the past several decades. Current management of CKD largely consists of supportive care, focused mainly on controlling high blood pressure with medications. Therefore, there is a large unmet medical need for therapies that can delay or prevent progression of kidney disease, preserve kidney function and improve quality of life for people living with kidney disease. We are focused initially on developing atrasentan and BION-1301 in IgAN and other proteinuric glomerular diseases.

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Immunoglobulin A Nephropathy (IgAN)

IgAN is the most common primary glomerular disease in the developed world and a leading cause of CKD and ESKD, requiring dialysis or kidney transplantation. Although the disease may follow a benign clinical course in many patients, it is estimated that up to 45 percent of IgAN patients will develop ESKD, requiring dialysis or kidney transplant, over a period of 20 to 25 years. IgAN is most commonly diagnosed in the second or third decade of life and more commonly affects males in North America and Europe, while having equal gender prevalence in Asia. There is considerable regional and ethnic variation in the epidemiology of IgAN, with a higher incidence in Caucasians and Asians and a lower incidence in individuals of African descent. Limited data from population-based studies in the United States indicate that the annual incidence of biopsy-proven disease is approximately one per 100,000, giving rise to a lifetime risk of approximately one per 1,400 adults.

Recent research has suggested that an abnormal mucosal immune response stimulating the production of Gd-IgA1 (Hit 1), which is recognized as an autoantigen by circulating autoantibodies (Hit 2), may be the initiating event causing IgAN. As demonstrated in the figure below, immune recognition results in the formation of pathogenic immune complexes (Hit 3) that deposit in the kidney and activate mesangial cells (Hit 4), which are key cells in the kidney that provide structural support to the glomerulus. Activated mesangial cells proliferate and produce excess amounts of extracellular matrix components, such as cytokines and

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chemokines. Mesangial cell-podocyte crosstalk results in proteinuria, which is a key driver of disease progression and subsequent kidney function loss.

Excessive tubular reabsorption of filtered proteins is thought to stimulate a pro-inflammatory response in tubular epithelial cells that results in the secretion of cytokines, chemokines, growth factors and vasoactive molecules into the tubulointerstitial space. This results in interstitial inflammation and fibrosis, which drives kidney function decline.

The clinical presentation of IgAN is heterogenous and can range from intermittent hematuria and low-level proteinuria with a benign clinical course over time and a low risk of progression to ESKD, to a more aggressive form with high levels of proteinuria and rapid loss of kidney function. Given the variable disease course, a major advance in the care of IgAN patients is the recognition of prognostic factors that can identify patients at greater risk of progression to ESKD. These prognostic markers include the presence of hypertension, evidence of reduced eGFR, and the presence of sustained proteinuria of more than one gram per day. These factors, in addition to biopsy histologic characteristics, prior medication use and race/ethnicity, have given rise to a risk prediction tool that can stratify newly diagnosed patients into risk groups. Of these various factors, the strongest risk factor for rapid progression, identified through multivariate analyses, is sustained proteinuria. The importance of this factor was demonstrated in multiple studies showing

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that proteinuria over one gram per day was associated with more rapid kidney function loss in a dose-dependent fashion, and that interventions that reduce proteinuria to below one gram per day led to decreased risk of kidney failure. Therefore, clinical management of IgAN is focused on reduction of proteinuria in order to slow progression of kidney function loss.

Importantly, in patients whose proteinuria at diagnosis was greater than three grams per day, treatments that resulted in proteinuria reduction to less than one gram per day generally led to slowing of kidney function loss to a rate that was comparable to those with less than one gram per day proteinuria values at diagnosis. It is estimated that for every one-gram per day increase in proteinuria over a baseline of one gram per day there is a 10 to 25-fold higher risk of kidney failure.

The primary focus of patient management is to control glomerular pressure through the administration of hypertension medications, such as angiotensin converting enzyme inhibitors, or ACE inhibitors, and angiotensin II receptor blockers, or ARBs, as well as lifestyle management such as dietary salt restriction, smoking cessation, weight control and exercise. Patients who fail conservative management and continue to have levels of proteinuria greater than one gram per day have limited established safe and effective treatment options. Current treatment guidelines suggest that a six-month course of glucocorticoids can be administered to these patients, although the potential for toxicity needs to be carefully considered. In December 2021, the FDA approved a corticosteroid treatment called Tarpeyo (budesonide) for patients with IgAN at risk of rapid progression, which is generally a UPCR > 1.5g/g. Tarpeyo was approved under accelerated approval based on a reduction in proteinuria, and it has not been established whether Tarpeyo slows kidney function decline in patients with IgAN. Historically, the evidence in support of the use of corticosteroids is of low quality, and any benefit in renal protection may potentially be offset by important systemic acute and chronic toxicities. The evidence to support use of corticosteroids as well as other immunosuppressants such as rituximab, cyclophosphamide and mycophenolate mofetil remains unclear and practice patterns vary widely. Therefore, there is an important unmet medical need to develop therapies for patients with IgAN who remain at risk for progressive renal function loss despite optimal conservative management.

Other Proteinuric Glomerular Diseases

Many glomerular diseases, such as FSGS, Alport syndrome, membranous nephropathy and sickle cell nephropathy, include proteinuria as an important feature in disease progression. These glomerular diseases currently have very limited treatment options that often involve immunosuppressive therapy. For example, FSGS is an important cause of ESKD. There are currently no FDA-approved pharmacologic treatments for FSGS, and off-label treatments are limited to ACE inhibitors and ARBs, steroids and other immunosuppressant agents, which are effective in only a subset of patients. The global incidence of FSGS has been estimated at eight per million people and we estimate that there are approximately 40,000 FSGS patients in the United States and a similar number in Europe. Additionally, Alport syndrome is a rare, genetic form of CKD caused by mutations in the genes encoding type IV collagen, which is a major structural component of the glomeruli in the kidney. Patients with Alport syndrome experience a progressive worsening of the kidney’s capacity to filter waste products out of the blood, which can lead to ESKD and the need for chronic dialysis treatment or a kidney transplant. Alport syndrome affects both children and adults. In patients with the most severe forms of the disease, approximately 50 percent progress to dialysis by age 25, 90 percent by age 40, and nearly 100 percent by age 60. According to the Alport Syndrome Foundation, the disease affects approximately 30,000 to 60,000 people in the United States. There are currently no approved therapies to treat Alport syndrome, and current management focuses on blood pressure control.

Our Product Candidates

Atrasentan

Our lead product candidate is atrasentan, a potent and selective endothelin A receptor antagonist that we are developing for the treatment of proteinuric glomerular diseases. Atrasentan is designed to reduce proteinuria and slow the progression of IgAN. In March 2021, we initiated a phase 3 trial of atrasentan called ALIGN for the treatment of IgAN, and in April 2021, we initiated a phase 2 basket trial called AFFINITY for the treatment of other proteinuric glomerular diseases.

Endothelin System in Chronic Kidney Disease

The endothelin, or ET, system consists of three peptides, ET-1, ET-2 and ET-3, which typically act locally. ET-1 is considered of most biological relevance to kidney physiology and disease. Two ET receptors, ET_A and ET_B, mediate the effects of the ET peptides. ET_A receptor activation typically results in blood vessel constriction, cellular proliferation and extracellular matrix deposition, whereas ET_B activation generally opposes these effects producing blood vessel dilation, antiproliferative and antifibrotic responses.

In kidney physiology, the ET system modulates regional kidney blood flow, mesangial cell and podocyte function and tubular acid/base handling. The ET system also regulates sodium and water excretion, so blockade of ET receptors can be accompanied by fluid retention, which is a known clinical observation with this class of agents.

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The kidney ET system is activated in virtually all causes of experimental and human CKD in which it has been investigated, irrespective of the initiating cause. Activation of the ET_A receptor by ET-1 has been implicated as a key driver of proteinuria, renal cell injury, including podocyte dysfunction and mesangial cell activation, along with promoting kidney inflammation and fibrosis, all resulting in the progression of CKD. The key effects of ET_A activation in CKD are shown in the figure below.

ET-1 is the most potent and long-lasting vasoconstrictor that has been identified. This effect of ET-1 contributes to systemic and local increases in blood pressure in the kidney that support the progression of CKD. While this effect can help maintain glomerular filtration rate, or GFR, in the short term, ultimately, it is maladaptive and a central driver of kidney damage and CKD progression.

ET_A activation also appears to have additional direct negative effects in CKD, independent of its effects on blood pressure. These additional effects include increased permeability of the glomerular filtration barrier to proteins leading to proteinuria, mesangial cell activation and kidney inflammation and fibrosis. Pharmacological studies indicate that these pathogenic effects are primarily mediated by the ET_A receptor. Combined, these observations have encouraged the investigation of ET_A inhibition as a potential therapeutic strategy in CKD.

ET pathway activation has been documented in patients with IgAN. High kidney levels of ET-1 are often seen in patients with IgAN with high levels of proteinuria, and predict rapid progression of IgAN. Selective inhibition of ET_A was studied in a clinical trial of proteinuric CKD patients without diabetes, with the selective ET_A inhibitor sitaxsentan. In this study, sitaxsentan was shown to reduce proteinuria by approximately 30 percent in this proteinuric CKD population including individuals with IgAN. In addition, ET_A blockade with sitaxsentan reduced arterial stiffness and appeared to be well tolerated with no clinically significant adverse effects reported. However, sitaxsentan was subsequently removed from the market due to liver toxicity believed to be specifically associated with the chemical structure of sitaxsentan and unrelated to ET_A inhibition.

Mechanism of Action of Atrasentan

Atrasentan is designed to be a potent, selective blocker of the ET_A receptor, and to reduce proteinuria, kidney inflammation and fibrosis, and delay the progression of kidney function loss. In preclinical studies, atrasentan has shown substantially more potency as an ET_A receptor antagonist than ET_B, with an ET_A inhibition constant [Ki] = 0.034 nanomolar, or nM, more than 1,800-fold selective

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over ET_B ([Ki] = 63.3 nM). We believe atrasentan has the required selectivity profile for therapeutic benefit in CKD, while minimizing the potential for fluid retention.

Previous Clinical Development of Atrasentan

We in-licensed atrasentan from Abbvie in late 2019. Before AbbVie made the strategic decision to terminate development of atrasentan, it had been investigated in multiple phase 1, 2 and 3 clinical trials involving approximately 622 healthy volunteers, and more than 5,000 patients with diabetic nephropathy. Atrasentan is designed to be orally bioavailable, readily absorbed with linear dose proportionality and administered once daily. Dedicated pharmacokinetic studies in special populations have demonstrated that no dose adjustment was needed based on race, degree of renal impairment, or mild or moderate hepatic impairment. Population pharmacokinetic studies have shown that the only factor significantly affecting atrasentan exposure was body weight. In prior trials, the recommended dose for evaluating atrasentan in patients with diabetic nephropathy was determined to be 0.75 mg daily, which resulted in the greatest proteinuria reduction with least fluid retention.

Atrasentan demonstrated a statistically significant and clinically meaningful reduction in proteinuria, as assessed by urine albumin to creatinine ratio, or UACR, in multiple phase 2 and phase 3 trials in diabetic nephropathy patients. In these trials, the change in UACR was generally observed within the first two weeks after treatment initiation and remained stable thereafter for the duration of chronic administration. Across phase 2 and phase 3 trials, the placebo-adjusted mean reduction in proteinuria was approximately 30 to 35 percent, although considerable intra-subject and inter-subject variability has been observed.

From 2013 to 2017, AbbVie conducted the global phase 3 SONAR trial, which was a randomized, double-blind, parallel, placebo-controlled, multicenter study designed to assess the effects of atrasentan on renal outcomes in patients with type 2 diabetes and CKD while they continued to be treated with the current standard of care. Despite early termination of the trial by AbbVie in 2017 for strategic reasons and due to a lower than anticipated accrual of primary endpoint events, patients who remained on trial and reached the primary endpoint of at least a 30 percent reduction in UACR following an initial six-week open label enrichment period with daily atrasentan experienced a clinically important and statistically significant improvement on the primary composite renal endpoint of time to doubling of serum creatinine or progression to ESKD (p-value=0.029). A similarly favorable trend was also observed in a smaller cohort of patients with a less than 30 percent UACR reduction in response to atrasentan following the six-week enrichment period (p-value=0.15).

The following figure shows mean UACR change from baseline to recovery for the placebo, 0.75 milligrams per day, or mg/d, atrasentan, and 1.25 mg/d atrasentan groups in AbbVie’s phase 2b RADAR trial. The RADAR trial was a randomized, double-blind, placebo-controlled trial completed in 2012 that tested in 161 patients the effects of atrasentan on albuminuria reduction in patients with type 2 diabetes and nephropathy who were treated with the maximum tolerated labeled dose of a Renin Angiotensin System, or RAS, inhibitor.

The following figure shows the mean UACR levels in SONAR among the patients that experienced at least a 30 percent reduction in UACR following the initial six-week open label enrichment period. Among these 2,648 patients, UACR decreased from

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baseline by an average of 51.8 percent during the enrichment period. During the double-blind period, UACR increased in the placebo group as compared to the atrasentan group (a difference of 33.6 percent, p-value<0.0001).

We believe the observed reduction in UACR across multiple clinical trials, as well as the favorable results observed on long-term renal outcomes, provide strong rationale for clinical evaluation of atrasentan in IgAN, a disease in which clinical management is centered around proteinuria reduction.

The most common and consistent safety findings across clinical studies of atrasentan in the diabetic nephropathy patient population were fluid retention and associated manifestations and dilutional anemia. In the phase 3 SONAR trial, fluid retention events were reported in approximately 26 percent of atrasentan-treated patients within the first six weeks. During the double-blind period, events of fluid retention were higher in the atrasentan groups (36.6 percent) than placebo groups (32.3 percent); however, across the population, atrasentan was associated with less than a one-kilogram increase in body weight and a six percent increase in brain natriuretic peptide levels, which is a peptide that is associated with fluid retention. In the phase 3 SONAR trial for patients with diabetic kidney disease, atrasentan was associated with a numerically higher, but not statistically significantly increased risk of heart failure hospitalizations due to fluid retention. Over time, anemia events were reported in approximately 18 percent of atrasentan patients compared with ten percent of placebo treated patients, with mean change in hemoglobin between groups of approximately one g/dL; these findings are consistent with mechanism-based hemodilution. Notably, there were no significant differences in adverse events leading to discontinuation during the double-blind treatment period between atrasentan and the placebo group.

As a class, endothelin receptor antagonists have a well-characterized embryo-fetal toxicity profile, resulting in Risk Evaluation and Mitigation Strategies, or REMS, programs and mandatory birth control for women of child-bearing age. We expect the FDA to require similar restrictions on the use of atrasentan, if approved. The endothelin system is also known to play a role in spermatogenesis, and although atrasentan was linked to reduced sperm concentrations in a small study (n=17) evaluating the effect of atrasentan on sperm concentration, sperm concentrations subsequently recovered in the four affected patients to within the normal range following drug discontinuation. The impact of long-term atrasentan treatment on spermatogenesis and male fertility is not known.

We expect that the patient population in the phase 3 ALIGN trial of atrasentan will be younger and have fewer cardiovascular co-morbidities than in the SONAR study. While patients in each clinical trial have a unique set of baseline characteristics, the mean ages of patients in two previous clinical trials in IgAN conducted by competitors were both 39 years old, while the mean age of patients in the SONAR trial was 65 years old. Additionally, patients with diabetic kidney disease are at greater risk of myocardial infarction, congestive heart failure and stroke than the non-diabetic population.

The diuretic effects achieved with SGLT2 inhibitors may offset the fluid retention effects of atrasentan, while the effects on albuminuria and kidney protection of both drug classes may be complementary due to distinct mechanisms of action. A third-party post-hoc analysis of the SONAR trial showed that in patients with type 2 diabetes and chronic kidney disease, six-weeks of treatment with atrasentan combined with an SGLT2 inhibitor versus atrasentan alone decreased body weight, a surrogate for fluid retention, and

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further decreased albuminuria. We believe this data supports future exploration of the long-term efficacy and safety of atrasentan in combination with SGLT2 inhibitors in IgAN.

Rationale for Atrasentan Development in IgAN

Chronic proteinuric kidney diseases, including IgAN and other proteinuric glomerular diseases, are characterized by progressive renal function loss, accompanied by excessive levels of urinary protein excretion, and have been proposed to progress by a final common pathway, irrespective of initiating cause. Glomerular hypertension, a maladaptive response to reduced kidney function, along with increased glomerular permeability results in the increased filtration of plasma proteins, which causes proteinuria. The consequent excess exposure of protein to glomerular and tubular epithelial cells has been shown preclinically to play a key pathogenic role in the progression of CKD. Kidney cells exposed to an excessive protein load release pro-fibrotic factors that can act locally to drive glomerulosclerosis. In vitro and in vivo studies have been used to develop a model of the final common pathway whereby excessive tubular reabsorption of filtered proteins stimulates a pro-inflammatory response that results in the secretion of cytokines, chemokines, growth factors and vasoactive molecules into the tubulointerstitial space. This results in interstitial inflammation and fibrosis, which drive renal function decline.

Clinical evidence consistent with proteinuria as a causal factor in CKD pathogenesis includes the observation that proteinuria is an independent predictor of disease progression. In IgAN, there appears to be a dose-dependent effect of proteinuria on the risk of renal progression, beginning at a urinary protein excretion rate of greater than one gram per day, with increasing levels of proteinuria associated with increased risk of ESKD. Sustained proteinuria has demonstrated to be the most important predictor of the rate of kidney progression in IgAN and sustained improvements in proteinuria to less than one gram per day are associated with an excellent long-term prognosis. The finding that the rate of eGFR decline correlates negatively with proteinuria reduction and positively with residual proteinuria provides further evidence for the pathogenetic role of proteinuria in CKD progression.

In preclinical studies, atrasentan has protected the kidney in nondiabetic CKD and has also been shown to reduce proteinuria and reduce the risk of progression to ESKD clinically in type 2 diabetics with CKD. In addition, a different ET_A antagonist significantly reduced proteinuria, diminished glomerular hypercellularity and prevented the loss of kidney function in a mouse model of IgAN. Further, in a randomized, double-blind, placebo and active controlled study in proteinuric CKD subjects already achieving optimal RAS inhibition, over half of which had biopsy-proven IgAN, selective ET_A antagonist sitaxsentan significantly reduced proteinuria and substantially reduced measured GFR and effective filtration fraction, consistent with a reduction in intraglomerular hypertension.

We are investigating atrasentan in IgAN based on the scientific rationale for targeting endothelin signaling, the strong association between high levels of protein excretion in IgAN and kidney function loss, the extent of clinical data demonstrating protein-lowering effects of atrasentan and other endothelin antagonists, the potential for a better tolerated dosing regimen in the IgAN patient population, and the clear unmet medical need for specific therapies to slow disease progression to ESKD.

Proteinuria as a Surrogate Marker for IgAN

CKD trials have typically relied on clinical outcomes for the primary endpoint, such as time to first occurrence of doubling of serum creatinine or ESKD (dialysis or transplantation). This generally requires very large trials of long duration, which have proved challenging in IgAN. The Kidney Health Initiative, or KHI, a partnership between the American Society of Nephrology and the FDA launched a project in 2016 to identify surrogate endpoints that could serve as reliable predictors of a treatment’s effect on long-term kidney outcomes in IgAN and be used as a basis for accelerated approval. Surrogate endpoints are used in clinical trials as a substitute for a direct measure of how a patient feels, functions or survives and although they do not measure the clinical benefit of primary interest, they are expected to predict that clinical benefit. The KHI project focused on proteinuria reduction as the most widely recognized and studied risk factor for progression to ESKD in IgAN and found a consistent relationship between the level and duration of proteinuria and loss of kidney function from epidemiologic studies. In addition, trial-level analyses of 13 randomized IgAN clinical trials showed a strong association between treatment effects on percent reduction of proteinuria at approximately nine months (measurements ranged from seven to 12 months) and treatment effects on a composite of time to doubling of serum creatinine, ESKD, or death. The analyses also indicated that the reduction of proteinuria must be sustained to confer protection against progressive loss of GFR. The KHI project concluded that proteinuria reduction is a surrogate endpoint reasonably likely to predict a treatment’s effect on progression to ESKD in IgAN. In the United States, surrogate endpoints reasonably likely to predict clinical benefit can be used as a basis for accelerated approval of therapies intended to treat serious or life-threatening conditions, such as IgAN. The predicted clinical benefit of products granted accelerated approval need to be verified in a post-marketing confirmatory trial.

A recently published meta-analysis of 12 randomized clinical trials in IgAN to compare treatment effects on change in proteinuria to change in eGFR slope, provides new evidence supporting that early reduction in proteinuria can be used as a surrogate endpoint for studies of CKD progression in IgAN.

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Ongoing Phase 3 ALIGN Trial of Atrasentan for the Treatment of IgAN

The ALIGN study, a phase 3, randomized, double-blind, placebo-controlled study of atrasentan in patients with IgAN at risk of progressive loss of kidney function, is designed to evaluate change from baseline in proteinuria and eGFR in 320 patients with IgAN. We have designed the trial in collaboration with a steering committee composed of leading global experts in glomerular diseases and are evaluating atrasentan at 0.75 mg daily, the dose used in the SONAR trial. The primary endpoint of the trial is change from baseline in proteinuria in the first 270 patients at six months post randomization. The key secondary endpoint is change from baseline in eGFR after all 320 patients have completed approximately two and half years of treatment. This global study is expected to be conducted in approximately 15-20 countries on four continents at approximately 160-170 investigative sites. We initiated the trial in March 2021 and anticipate data for the primary proteinuria endpoint in 2023 to support potential accelerated approval.

We have held a Type B End of phase 2 meeting with the FDA to discuss the design of the ALIGN trial and, if the data from the trial are positive, we plan to seek approval of an NDA under the accelerated approval pathway in the United States. Additionally, we have also received feedback on the study design from the EMA and the Pharmaceuticals and Medical Devices Agency, or PMDA, in Japan. Based upon this feedback, we believe that upon completion, the ALIGN trial could serve as the basis of a successful marketing authorization application, or MAA, in European countries, Japan, China and other countries.

Ongoing Phase 2 AFFINITY Basket Trial for the Treatment of Other Proteinuric Glomerular Diseases

In April 2021 we initiated a phase 2 basket study of atrasentan called AFFINITY in several populations of proteinuric glomerular disease patients. Four initial cohorts will include IgAN patients with lower levels of proteinuria (UPCR >0.5g/g <1.0 g/g urine protein/creatinine), FSGS, Alport syndrome, and diabetic kidney disease combined with an SGLT2 inhibitor. Approximately 20 patients are planned to be treated with open-label atrasentan in each cohort. The primary endpoint for each cohort will be the change from baseline in proteinuria at 12 weeks. Additional cohorts may be added to the basket study. We plan to present data from the IgAN patient cohort of the AFFINITY trial in an oral presentation at the ERA Congress in May 2022, and one or more additional cohorts of the AFFINITY trial during the second half of 2022, and believe the study will provide signal-seeking data to inform our life cycle management strategy for atrasentan.

BION-1301

Our second product candidate, BION-1301, is an investigational humanized IgG4 monoclonal antibody that blocks APRIL binding to its receptors and is being developed as a novel disease-modifying therapy for IgAN. BION-1301 is currently in an ongoing phase 1/2 clinical trial for patients with IgAN.

We believe the key attributes of our BION-1301 product candidate include:

Patients with IgAN have significantly higher levels of APRIL than healthy individuals, and higher APRIL levels in these patients correlate with poor prognosis in the form of increased Gd-IgA1, increased proteinuria and decreased eGFR. We know from published literature that APRIL critically drives IgA class switching, the survival of IgA-producing plasma cells and the secretion of Gd-IgA1 (Hit 1 in the multi-hit pathogenesis of IgAN). Our preclinical experiments demonstrate that blocking APRIL inhibits the survival of and immunoglobulin production by human plasma cells. We have also demonstrated that IgA-producing plasma cells are more sensitive to immunomodulation by BION-1301, with a lesser effect observed on IgG, providing the potential to deplete IgA with BION-1301, while tempering effects on IgG and minimizing the potential for immunosuppression associated with IgG depletion.

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Blocking APRIL with BION-1301 is a distinct approach to IgAN by reducing circulating levels of Gd-IgA1 which is considered to be the pathogenic variant of IgA in IgAN. We believe BION-1301 represents a novel potential disease-modifying treatment for IgAN.

Preclinical studies have demonstrated that BION-1301 binds to a specifically defined epitope on APRIL, resulting in complete blockade of APRIL-induced receptor activation. In a preclinical study of BION-1301 in non-human primates, we observed a significant reduction of blood IgA levels and a favorable safety profile. Additional preclinical studies demonstrated that APRIL transgenic mice produce rising levels of IgA as well as IgA deposits in the kidney. Administration of mouse anti-human APRIL was shown to reduce levels of IgA in both the serum and the kidney. In patients with IgAN, BION-1301 has been shown to neutralize APRIL and deplete Gd-IgA1, resulting in clinically meaningful reductions in proteinuria. The illustration below shows the potential reduction of immune complex formation in the kidneys by BION-1301 and its effect in IgAN.

In May 2019, we initiated a phase 1/2 clinical trial evaluating BION-1301 in healthy volunteers and patients with IgAN. The phase 1/2 multi-center trial evaluated the safety and tolerability of BION-1301 in 63 healthy volunteers in double-blinded, placebo-controlled single-ascending dose, or SAD, and multiple-ascending dose, or MAD, settings. Healthy volunteers in the SAD portion of the study (Part 1) received placebo or a single IV dose of BION-1301 ranging from 10 mg to 1350 mg on day 1. Healthy volunteers in the MAD portion of the study (Part 2) received placebo or IV doses of BION-1301 ranging from 50 mg to 450 mg on days 1, 15 and 29 (three doses total).

We presented data from Parts 1 and 2 of the study in healthy volunteers at the 57^th ERA-EDTA Virtual Congress in June 2020 and ASN Kidney Week 2020 Reimagined. BION-1301 was well-tolerated, with no significant adverse events, treatment discontinuations or events meeting stopping criteria, across a wide range of doses. Non-neutralizing ADAs occurred in less than 10 percent of subjects with no correlation to dose. The PK profile of BION-1301 was well-behaved, generally dose proportional, and had a half-life of approximately 33 days, suggesting the potential for an extended dosing interval. BION-1301 demonstrated a dose-dependent increase in target engagement as measured by free APRIL levels in serum; over 90 percent target engagement was achieved

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with a single 450 mg dose. BION-1301 dose-dependently and durably reduced IgA and IgM levels, and to a lesser extent, IgG levels. Approximately 50 to 60 percent reduction in IgA levels was achieved with 150 mg to 450 mg of BION-1301. At all doses tested, IgG levels remained in the normal lab range, thereby providing a PD window to potentially exploit reductions in IgA, while tempering reductions in IgG. Additional data in healthy volunteers from this trial were presented at WCN’21. BION-1301 produced dose-dependent reductions in serum Gd-IgA1 levels that were greater in magnitude than previously reported for total IgA concentrations.

In addition, we have completed a phase 1 IV to SC bioavailability study in healthy volunteers. Results from this study were presented at WCN‘21. In this study, BION-1301 was well-tolerated when administered by both IV and SC routes in healthy volunteers, the pharmacokinetic profile of BION-1301 was consistent with previous clinical studies, the absorption rate of BION-1301 was typical of a monoclonal antibody and the magnitude of pharmacodynamic responses were largely retained with SC dosing compared to IV dosing.

We are currently enrolling patients with IgAN in Cohort 2 of Part 3 of a phase 1/2 trial in which patients with IgAN are dosed with 600 mg of BION-1301 SC every two weeks for up to 52 weeks. We presented data from Cohort 1 of Part 3 of this trial, in which patients were dosed with 450 mg of BION-1301 IV every two weeks, at ASN Kidney Week 2021 in early November. The data presented at the conference demonstrated that BION-1301 was generally well-tolerated to date in patients with IgAN, with no serious adverse events or treatment discontinuations due to adverse events. The pharmacokinetics of BION-1301 observed in patients with IgAN are consistent with those previously reported in healthy volunteers and, as demonstrated in the figures below, are sufficient to drive rapid and sustained reductions in free APRIL levels, as well as durable reductions in Gd-IgA1, IgA, IgM, and to a lesser extent, IgG levels. BION-1301 demonstrated a greater than fifty percent (50%) geometric mean reduction in 24-hour urine protein creatinine ratio (UPCR) in patients with IgAN after three (n=6) to six months (n=4) of treatment, a clinically meaningful result in this patient population. We plan to present additional data from Cohort 1 of Part 3 of this trial in a mini-oral presentation at the ERA Congress in May 2022, and additional data from Cohort 2 of Part 3 of this trial in the second half of 2022.

Recent amendments to the design of Part 3 also include the option for a third cohort of patients to receive a SC dose of BION-1301 at a dose and schedule that would be determined based on data generated from Cohort 2. Moving forward with Cohort 3 may help us better understand the SC dose-response relationship prior to moving into a pivotal trial in IgAN, which we anticipate initiating in 2023.

CHK-336

Our third product candidate is CHK-336, a liver-targeted oral small molecule LDHA inhibitor, which we are developing for the treatment of PH, secondary hyperoxaluria, and idiopathic kidney stone formation. Hyperoxalurias, including PH, are diseases caused by excess oxalate, a potentially toxic metabolite typically filtered by the kidneys and excreted as a waste product in urine. Symptoms

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of PH include recurrent kidney stones, which when left untreated, can result in kidney failure requiring dialysis or dual kidney/liver transplantation. In patients with hyperoxalurias, excess oxalate combines with calcium to form calcium oxalate crystals that deposit in the kidney, resulting in the formation of painful kidney stones and driving progressive kidney damage over time. PH1, PH2 and PH3 are a group of ultra-rare diseases caused by genetic mutations that result in excess oxalate, and in their most severe forms, can lead to end-stage kidney disease at a young age. We also believe CHK-336 may have potential in the treatment of patients with secondary hyperoxaluria and idiopathic stone formation. We are advancing CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022 for the treatment of PH.

As seen in the illustration below, LDHA catalyzes the terminal step in the production of oxalate from glyoxylate in the liver, therefore LDHA inhibition has the potential to treat all forms of PH – PH1, PH2 and PH3 – as well as other disorders arising from excess oxalate. This is a point of differentiation for CHK-336 since inhibition using small molecules or silencing using small-interfering RNAs (siRNAs) of glycolate oxidase (GO), the enzyme involved in the production of glyoxylate from glycolate, is limited to the treatment of PH1 only. An oral, liver-targeted LDHA small molecule inhibitor has the potential for robust efficacy by rapidly distributing to the site of oxalate production, while minimizing systemic exposures and potential for off-target activity, to facilitate a favorable tolerability profile required in this chronic disease.

With the goal of developing a best-in-class treatment applicable to all types of PH, our research team designed, synthesized and characterized hundreds of LDHA inhibitors to engineer the required properties of potent and selective LDHA inhibition with a liver-targeted tissue-distribution profile. We designed CHK-336 to demonstrate a promising preclinical pharmacokinetic and safety profile.

In preclinical studies, CHK-336 has demonstrated tight LDHA binding and a slow enzyme off-rate, potentially extending the duration of action and enabling the potential of a once-daily oral dose in humans. In order to maximize efficacy and reduce the potential for any systemic toxicities as is observed with complete loss-of-function of LDHA, our team engineered into CHK-336 a liver-targeted tissue distribution profile by incorporating moieties that result in liver-selective OATP transporter uptake and simultaneously reducing non-specific passive permeability.

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To evaluate efficacy, we generated a novel mouse model of PH1 using CRISPR-Cas9 gene editing to delete the AGXT gene responsible for PH1 in humans, which created mice with significantly elevated urinary oxalate excretion compared to normal wild-type (WT) control mice. CHK-336 was dosed orally at three different dose levels, once-daily for seven days and urinary oxalate excretion was compared to a control group of PH mice treated with vehicle. As demonstrated in the figure below, CHK-336 demonstrated significant dose-dependent reductions in urinary oxalate levels, with the majority of CHK-336 treated mice reaching the normal range seen in WT mice.

We have submitted an IND and are advancing CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022 for the treatment of PH. We believe clinical proof of concept for CHK-336 can be achieved efficiently in small studies using urinary oxalate as a validated surrogate biomarker and primary endpoint with the potential for full approval of this program in PH. We have also received rare pediatric disease designation from the FDA for CHK-336 for the treatment of PH.

Preclinical Product Candidates

In addition to our lead product candidates, we are also conducting discovery and research efforts to develop a pipeline of product candidates in other rare, severe chronic kidney diseases.

We have initiated drug discovery programs against promising biological targets across kidney disease indications with high unmet medical need selected in alignment with our guiding precision medicine principles:

To supplement our internal research efforts, we have entered into a strategic collaboration with Evotec focused on the discovery and development of novel precision medicine therapies for patients with chronic kidney diseases. Based on Evotec’s proprietary comprehensive molecular datasets from thousands of patients across chronic kidney diseases of multiple underlying etiologies, we and Evotec will jointly identify, characterize and validate novel mechanisms and discover precision medicines for lupus nephritis, IgAN, PKD, and other primary glomerular diseases. The collaboration will also involve further characterization of pathways and patient stratification strategies for programs currently in Chinook’s clinical and preclinical pipeline.

Gaining access to the NURTuRE cohort study and other proprietary patient biobanks, along with Evotec’s multi-omics integration platform, enables us to characterize the molecular drivers of kidney diseases, identify and validate novel targets and drive patient stratification strategies in kidney disease. With a focus on comprehensive molecular disease classification, combined with prospective clinical outcomes, we believe we have the opportunity to potentially deliver targeted therapies to the right patient populations.

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License Agreements

AbbVie

In December 2019, we entered into an agreement with AbbVie, through its affiliate AbbVie Ireland Unlimited Company for an exclusive, sublicensable, worldwide license to atrasentan, along with claims in several issued patents and associated know-how, to manufacture, have manufactured, use and sell defined licensed products for use within the field of all human and non-human diagnostic, prophylactic, and therapeutic uses. Under the terms of this license, we paid an initial licensing fee and issued AbbVie 1,999,415 shares of common stock. The license agreement requires us to pay potential milestone payments totaling up to $135 million upon the achievement of certain developmental, regulatory and commercial milestones, as well as royalties ranging from the high single digits to the high teens based on annual thresholds for net sales of licensed products by us, our affiliates and our sublicensees.

Under the AbbVie license, we have a continuing obligation to use commercially reasonable efforts to develop, obtain regulatory approvals and commercialize licensed products. The license agreement is effective on a per-country basis until the later of: (i) the last expiration of a claim in a licensed patent that covers the licensed product in such country, (ii) the expiration of any period of regulatory exclusivity for a licensed product that bars the entry of generic competitors in such country, or (iii) a specified period after the first commercial sale of the licensed product. Each party has the right to terminate the license for the other party’s material breach or in the event of the other party’s bankruptcy or insolvency, subject to specified notice and cure periods. Additionally, AbbVie can terminate the license if we challenge claims in licensed patents or fail to meet our diligence obligations with respect to licensed products. Upon any termination of the license, we may grant AbbVie an exclusive, sublicenseable license to any improvements that we make to the licensed technology, including those that we license from third parties, subject to a mutually agreed royalty.

Manufacturing

We currently contract with third parties to manufacture our products and anticipate using third parties for our clinical and commercial manufacturing. We do not own or operate facilities for product manufacturing, packaging, storage and distribution, or testing. We have internal personnel and utilize consultants with extensive technical, manufacturing, analytical and quality experience to oversee contract manufacturing and testing activities. We will continue to expand and strengthen our network of third-party providers but may also consider investing in internal manufacturing capabilities in the future if there is a technical need, or a strategic or financial benefit.

Manufacturing is subject to extensive regulations that impose procedural and documentation requirements. At a minimum these regulations govern record keeping, manufacturing processes and controls, personnel, quality control and quality assurance. Our systems, procedures and contractors are required to be in compliance with these regulations and are assessed through regular monitoring and formal audits.

Atrasentan. Under our license agreement with AbbVie, we received a substantial amount of drug product and drug substance to support clinical trials of atrasentan. We plan to resupply our clinical trials and prepare for future commercial launch with additional manufacturing campaigns conducted by AbbVie. In addition, we believe that the synthesis from regulatory starting material to drug substance can be manufactured at scale, resulting in a commercially competitive cost of goods.

BION-1301. We rely on third-party contract manufacturing organizations, or CMOs, to manufacture product for clinical use based on engineered cell lines that express and secrete the antibody product candidate. We have contracted with a CMO to develop, produce and release drug substance and drug product for use in the ongoing phase 1/2 clinical trial. We expect to continue to rely on CMOs for further manufacturing of BION-1301, including the development and manufacturing of alternative formulations.

CHK-336. In 2021, we continued manufacturing activities for CHK-336 initiated in 2020 to support IND-enabling studies.

Sales and Marketing

We do not currently have sales and marketing infrastructure to support commercial launch of our products. We intend to build such capabilities in North America prior to launch of atrasentan. Outside of North America, we may rely on licensing, co-sale and co-promotion agreements with strategic partners for the commercialization of our products, including the recently formed joint venture, SanReno Therapeutics, in East Asia. If we build a commercial infrastructure to support marketing in North America, such commercial infrastructure could be expected to include a targeted sales force supported by sales management, internal sales support, an internal marketing group and distribution support. To develop the appropriate commercial infrastructure internally, we would have to invest financial and management resources, some of which would have to be deployed prior to any confirmation that atrasentan will be approved.

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Coverage & Reimbursement

The regulations that govern pricing and reimbursement for new drugs vary widely from country to country. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing approval is granted. In some foreign markets, prescription biopharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, a drug company can obtain regulatory approval for a product in a country, but then be subject to price regulations that delay commercial launch of that product.

A drug company’s ability to successfully commercialize any products will also depend on the extent to which coverage and adequate reimbursement for these products will be available from government authorities, private health insurers and other organizations. Even if one or more products are successfully brought to the market, these products may not be considered cost effective, and the amount reimbursed for such products may be insufficient to allow them to be sold on a competitive basis. Third-party payors who reimburse patients or healthcare providers, such as government plans, are requiring that drug companies provide them with predetermined discounts from list prices and are seeking to reduce the prices charged or the amounts reimbursed for biopharmaceutical products.

Significant delays can occur in obtaining reimbursement for newly-approved drugs or therapeutic biologics, and coverage may be more limited than the purposes for which the drug or therapeutic biologic is approved by the FDA or similar foreign regulatory authorities. Moreover, eligibility for reimbursement does not imply that any drug will be reimbursed in all cases or at a rate that covers a drug company’s costs, including research, development, manufacture, sale and distribution.

Interim reimbursement levels for new drugs, if applicable, may also be insufficient to cover a drug company’s costs and may not be made permanent. Reimbursement rates may be based on payments allowed for lower cost drugs or therapeutic biologics that are already reimbursed, may be incorporated into existing payments for other services and may reflect budgetary constraints or imperfections in Medicare data. Net prices for drugs or therapeutic biologics may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs or therapeutic biologics from countries where they may be sold at lower prices than in the United States. Further, no uniform policy for coverage and reimbursement exists in the United States. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement rates, but also have their own methods and approval process apart from Medicare determinations. Therefore, coverage and reimbursement can differ significantly from payor to payor.

Competition

The biotechnology and biopharmaceutical industries are characterized by rapid evolution of technologies, fierce competition and vigorous defense of intellectual property. Any product candidates that we successfully develop and commercialize will have to compete with existing and future new therapies. While we believe that our technology, development experience and scientific knowledge provide us with competitive advantages, we face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions and governmental agencies, and public and private research institutions.

If our lead product candidate atrasentan is approved for the treatment of IgAN, it may compete with other products used to treat this disease. To our knowledge, there is only one FDA-approved drug for IgAN, the corticosteroid treatment Tarpeyo (budesonide), but there are a variety of additional treatments utilized, including renin angiotensin inhibitors, steroids, chemotherapy drugs and immunomodulatory approaches. In addition, there are a number of competitors in clinical development for the treatment of IgAN at a similar stage of development or more advanced than us, including AstraZeneca PLC, Calliditas Therapeutics AB, Novartis AG, Omeros Corporation, Reata Pharmaceuticals, Inc., Travere Therapeutics, Inc., Vera Therapeutics and Otsuka Pharmaceutical Co., Ltd.

Many of our potential competitors, alone or with strategic partners, may have substantially greater financial, technical and other resources than we do, such as larger research and development, clinical, marketing and manufacturing organizations. Accordingly, our competitors may be more successful than us in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining approval for treatments and achieving widespread market acceptance, rendering our treatments obsolete or non-competitive. Mergers and acquisitions in the biotechnology and biopharmaceutical industries may result in even more resources being concentrated among a smaller number of our competitors. These companies also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials and acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. Our commercial opportunity could be reduced or eliminated if competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or less expensive than any product candidates that we may develop. In geographies that are critical to our commercial success, competitors may also obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for our products, which could result in our competitors establishing a strong market position before we are able to

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enter the market, if ever. The key competitive factors affecting the success of all of our programs are likely to be their efficacy, safety, convenience and availability of reimbursement. In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic drugs.

Intellectual Property

We strive to protect and enhance the proprietary technology, inventions and improvements that are commercially important to our business, including obtaining, maintaining and defending patent rights, whether developed internally or licensed from third parties. Our policy is to seek to protect our proprietary position by, among other methods, pursuing and obtaining patent protection in the United States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements, platforms and product candidates that are important to the development and implementation of our business. Our patent portfolio, including in-licensed patents and patent applications, is intended to cover, but is not limited to, our technology platforms, product candidates and components thereof, their methods of use and processes for their manufacture, and any other inventions that are commercially important to our business. We also rely on trade secret protection of our confidential information and know-how relating to our proprietary technology, platforms and product candidates, continuing innovation, and in-licensing opportunities to develop, strengthen, and maintain our position in our platform and product candidates. Our commercial success may depend in part on our ability to obtain and maintain patent and other proprietary protection for our technology, inventions and improvements; to preserve the confidentiality of our trade secrets; to maintain our licenses to use intellectual property owned or controlled by third parties; to defend and enforce our proprietary rights, including our patents; to defend against challenges and assertions by third parties of their purported intellectual property rights; and to operate without infringement of valid and enforceable patents and other proprietary rights of third parties.

With respect to atrasentan, we have exclusively licensed issued U.S. and foreign patents and pending U.S. and foreign patent applications that cover formulations and methods of use related directly to atrasentan from AbbVie. These exclusively licensed patents included eight issued U.S. patents and three pending foreign patent applications. These patents, and any patents that issue from the pending applications, that we have licensed from AbbVie are anticipated to expire between 2028 and 2034, absent any patent term adjustments or extensions.

Separately, we have filed U.S. patent applications with claims that are intended to cover additional methods of treatment and combinations of atrasentan with other therapies in kidney disease. Any patents that may issue from these currently pending patent applications, which include PCT international applications, U.S. patent applications, and foreign patent applications, are expected to expire in 2040-2041, absent any patent term adjustments or extensions.

With respect to BION-1301, we have four issued U.S. patents, eleven issued foreign patents, one pending U.S. patent and 12 pending foreign patents, that cover the composition of matter of BION-1301, as well as methods of use. These patents, and any patents that issue from the pending applications are anticipated to expire between 2030 and 2041, absent any patent term adjustments or extensions.

With respect to CHK-336, we have in-licensed issued U.S. and foreign patents and have filed U.S. and foreign patent applications with claims that cover the composition of matter of CHK-336 and other related compounds, as well as methods of use. As of December 31, 2021, any patents that may issue from these currently pending patent applications, which include PCT international applications, U.S. patent applications, and foreign patent applications, are expected to expire in 2041, absent any patent term adjustments or extensions.

The term of individual patents depends upon the laws of the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing of a non-provisional patent application. However, the term of United States patents may be extended for delays incurred due to compliance with the FDA requirements or by delays encountered during prosecution that are caused by the United States Patent and Trademark Office, or the USPTO. For example, for drugs that are regulated by the FDA under the Hatch-Waxman Act, it is permitted to extend the term of a patent that covers such drug for up to five years beyond the normal expiration date of the patent. For more information on patent term extensions, see “—Government regulation—The Hatch-Waxman Act—Patent term extension.” In the future, if and when our biopharmaceutical product candidates receive FDA approval, we expect to apply for patent term extensions on patents covering those product candidates. We intend to seek patent term extensions to any of our issued patents in any jurisdiction where these are available; however, there is no guarantee that the applicable authorities, including the USPTO and FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions. Our currently issued patents will likely expire on dates ranging from 2028 to 2036, unless we receive patent term extension. If patents are issued on our pending patent applications, the resulting patents are projected to expire on dates ranging from 2036 to 2041, unless we receive patent term extension or patent term adjustment, or both. However, the actual protection afforded by a patent varies on a product-by-product basis, from country-to-country, and depends upon many factors, including the type of patent, the scope of its coverage, specific claims issues, the availability of regulatory-related extensions, the availability of legal remedies in a particular country and the validity and enforceability of the patent.

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The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. The patent situation outside of the United States is even more uncertain. Changes in the patent laws and rules, either by legislation, judicial decisions, or regulatory interpretation in the United States and other countries may diminish our ability to protect our inventions and enforce our intellectual property rights, and more generally could affect the value of our intellectual property. In particular, our ability to stop third parties from making, using, selling, offering to sell, importing or otherwise commercializing any of our patented inventions, either directly or indirectly, will depend in part on our success in obtaining, defending and enforcing patent claims that cover our technology, inventions, and improvements. With respect to both licensed and company-owned intellectual property, we cannot be sure that patents will be granted with respect to any of our pending patent applications or with respect to any patent applications filed by us in the future, nor can we be sure that any of our existing patents or any patents that may be granted to us in the future will be commercially useful in protecting our platform and product candidates and the methods used to manufacture them. Moreover, our issued patents and those that may issue in the future may not guarantee us the right to practice our technology in relation to the commercialization of our platform’s product candidates. The area of patent and other intellectual property rights in biotechnology is an evolving one with many risks and uncertainties, and third parties may have blocking patents that could be used to prevent us from commercializing our product candidates and practicing our proprietary technology. Our issued patents and those that may issue in the future may be challenged, narrowed, circumvented or invalidated, which could limit our ability to stop competitors from marketing related platforms or product candidates or limit the length of the term of patent protection that we may have for our product candidates. In addition, the rights granted under any issued patents may not provide us with protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies or third parties may seek to develop our clinical candidates in countries where we do not have patent protection. This risk may also affect our ability to partner rights in those countries. For these reasons, we may have competition for our product candidates. Moreover, because of the extensive time required for development, testing and regulatory review of a potential product, it is possible that before any product candidate can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent. For this and other risks related to our proprietary technology, inventions, improvements, platforms and product candidates, please see the section titled “Risk Factors—Risks Related to Our Intellectual Property.”

We have filed for trademark protection of the “Chinook Therapeutics” mark with the USPTO and foreign trademark registries. We intend to register and maintain the trademark “Chinook Therapeutics” in the USPTO and in numerous other jurisdictions, including, but not limited to, the European Union (EU), China, India, Switzerland, the United Kingdom, or UK, and Canada.

We also rely on trade secret protection for our confidential and proprietary information. Although we take steps to protect our confidential and proprietary information as trade secrets, including through contractual means with our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements under the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual during the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our exclusive property. In many cases our confidentiality and other agreements with consultants, outside scientific collaborators, sponsored researchers and other advisors require them to assign or grant us licenses to inventions they invent as a result of the work or services they render under such agreements or grant us an option to negotiate a license to use such inventions. Despite these efforts, we cannot provide any assurances that all such agreements have been duly executed, and any of these parties may breach the agreements and disclose our proprietary information, and we may not be able to obtain adequate remedies for such breaches.

We also seek to preserve the integrity and confidentiality of our proprietary technology and processes by maintaining physical security of our premises and physical and electronic security of our information technology systems. Although we have confidence in these individuals, organizations and systems, agreements or security measures may be breached, and we may not have adequate remedies for any breach. To the extent that our employees, contractors, consultants, collaborators and advisors use intellectual property owned by others in their work for us, disputes may arise as to the rights in relation to the resulting know-how or inventions. For more information, please see the section titled “Risk Factors—Risks Related to Our Intellectual Property.”

Government Regulation

Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products. The processes for obtaining regulatory approvals in the United States and in foreign countries

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and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

FDA Approval Process

In the United States, pharmaceutical products are subject to extensive regulation by the FDA, the Federal Food, Drug, and Cosmetic Act, or FD&C Act, and other federal and state statutes and regulations govern, among other things, the research, development, testing, manufacture, storage, recordkeeping, approval, labeling, promotion and marketing, distribution, post-approval monitoring and reporting, sampling and import and export of pharmaceutical products. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions, such as clinical hold, FDA refusal to approve pending NDAs, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties and criminal prosecution.

Pharmaceutical product development for a new product or certain changes to an approved product in the U.S. typically involves preclinical laboratory and animal tests, the submission to the FDA of an IND, which must become effective before clinical testing may commence, and adequate and well-controlled clinical trials to establish the safety and effectiveness of the drug for each indication for which FDA approval is sought. Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity and novelty of the product or disease.

Preclinical tests include laboratory evaluation of product chemistry, formulation and toxicity, as well as animal trials to assess the characteristics and potential safety and efficacy of the product. The conduct of the preclinical tests must comply with federal regulations and requirements, including Good Laboratory Practices, or GLP. The results of preclinical testing are submitted to the FDA as part of an IND along with other information, including information about product chemistry, manufacturing and controls, and a proposed clinical trial protocol. Long-term preclinical tests, such as animal tests of reproductive toxicity and carcinogenicity, may continue after the IND is submitted. A 30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. If the FDA has neither commented on nor questioned the IND within this 30-day period, the clinical trial proposed in the IND may begin. Clinical trials involve the administration of the investigational new drug to healthy volunteers or patients under the supervision of a qualified investigator. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with Good Clinical Practices, or GCP, an international standard meant to protect the rights and health of patients and to define the roles of clinical trial sponsors, administrators and monitors; as well as (iii) under protocols detailing the objectives of the trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. patients and subsequent protocol amendments must be submitted to the FDA as part of the IND.

The FDA may order the temporary, or permanent, discontinuation of a clinical trial at any time, or impose other sanctions, if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. The study protocol and informed consent information for patients in clinical trials must also be submitted to an institutional review board, or IRB, and ethics committee for approval. The IRB will also monitor the clinical trial until completed. An IRB may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or may impose other conditions. Additionally, some clinical trials are overseen by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board or committee. This group provides authorization for whether a trial may move forward at designated checkpoints based on access to certain data from the trial.

Clinical trials to support NDAs for marketing approval are typically conducted in three sequential phases, but the phases may overlap. In phase 1, the initial introduction of the drug into healthy human subjects or patients, the drug is tested to assess metabolism, pharmacokinetics, pharmacological actions, side effects associated with increasing doses, and, if possible, early evidence of effectiveness. Phase 2 usually involves trials in a limited patient population to determine the effectiveness of the drug for a particular indication, dosage tolerance and optimum dosage, and to identify common adverse effects and safety risks. If a drug demonstrates evidence of effectiveness and an acceptable safety profile in phase 2 evaluations, phase 3 trials are undertaken to obtain the additional information about clinical efficacy and safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to permit the FDA to evaluate the overall benefit-risk relationship of the drug and to provide adequate information for the labeling of the drug. In most cases the FDA requires two adequate and well-controlled phase 3 clinical trials to demonstrate the efficacy of the drug. A single phase 3 trial may be sufficient in rare instances, including (1) where the trial is a large multicenter trial demonstrating internal consistency and a statistically very persuasive finding of a clinically meaningful effect on mortality, irreversible morbidity or prevention of a disease with a potentially serious outcome and confirmation of the result in a second trial would be practically or ethically impossible or (2) when in conjunction with other confirmatory evidence.

The manufacturer of an investigational drug in a phase 2 or 3 clinical trial for a serious or life-threatening disease is required to make available, such as by posting on its website, its policy on evaluating and responding to requests for expanded access.

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After completion of the required clinical testing, an NDA is prepared and submitted to the FDA. FDA approval of the NDA is required before marketing of the product may begin in the U.S. The NDA must include the results of all preclinical, clinical and other testing and a compilation of data relating to the product’s pharmacology, chemistry, manufacture and controls.

The cost of preparing and submitting an NDA is substantial. The submission of most NDAs is additionally subject to a substantial application user fee, currently exceeding $3,100,000 for Fiscal Year 2022 for an application containing clinical data. Fee waivers or reductions are available in certain circumstances, including a waiver of the application fee for the first application filed by a small business. Additionally, no user fees are assessed on NDAs for products designated as orphan drugs, unless the product also includes a non-orphan indication. The applicant under an approved NDA are also subject to annual program fees, currently exceeding $360,000 for each prescription product. The FDA adjusts the user fees on an annual basis, and the fees typically increase annually.

The FDA reviews each submitted NDA before it determines whether to file it and may request additional information. The FDA must make a decision on whether to file an NDA within 60 days of receipt, and such decision could include a refusal to file by the FDA. Once the submission is filed, the FDA begins an in-depth review of the NDA. The FDA has agreed to certain performance goals in the review of NDAs. Most applications for standard review drug products are reviewed within ten to twelve months; most applications for priority review drugs are reviewed in six to eight months. Priority review can be applied to drugs that the FDA determines may offer significant improvement in safety or effectiveness compared to marketed products or where no adequate therapy exists. The review process for both standard and priority review may be extended by the FDA for three additional months to consider certain late-submitted information, or information intended to clarify information already provided in the submission. The FDA does not always meet its goal dates for standard and priority NDAs, and the review process can be extended by FDA requests for additional information or clarification.

The FDA may also refer applications for novel drug products, or drug products that present difficult questions of safety or efficacy, to an outside advisory committee—typically a panel that includes clinicians and other experts—for review, evaluation and a recommendation as to whether the application should be approved and under what conditions, if any. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations.

Before approving an NDA, the FDA will conduct a pre-approval inspection of the manufacturing facilities for the new product to determine whether they comply with Good Manufacturing Practices, or cGMP, requirements. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. The FDA also typically inspects clinical trial sites to ensure compliance with GCP requirements and the integrity of the data supporting safety and efficacy.

After the FDA evaluates the NDA and the manufacturing facilities, it issues either an approval letter or a complete response letter. A complete response letter, or CRL, generally outlines the deficiencies in the submission and may require substantial additional testing, or information, in order for the FDA to reconsider the application, such as additional clinical data, additional pivotal clinical trial(s), and/or other significant and time-consuming requirements related to clinical trials, preclinical studies or manufacturing. If a CRL is issued, the applicant may resubmit the NDA addressing all of the deficiencies identified in the letter, withdraw the application, engage in formal dispute resolution or request an opportunity for a hearing. The FDA has committed to reviewing resubmissions in two or six months depending on the type of information included. Even if such data and information are submitted, the FDA may decide that the NDA does not satisfy the criteria for approval.

If, or when, the deficiencies identified in the CRL have been addressed to FDA’s satisfaction in a resubmission of the NDA, the FDA will issue an approval letter. An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific indications. As a condition of NDA approval, the FDA may require a REMS to help ensure that the benefits of the drug outweigh the potential risks to patients. A REMS can include medication guides, communication plans for healthcare professionals, and elements to assure safe use, or ETASU. ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the drug. Moreover, product approval may require substantial post-approval testing and surveillance to monitor the drug’s safety or efficacy. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are identified following initial marketing.

Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of an NDA supplement or, in some case, a new NDA, before the change can be implemented. An NDA supplement for a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing NDA supplements as it does in reviewing NDAs.

Disclosure of Clinical Trial Information

Sponsors of clinical trials of FDA regulated products, including drugs, are required to register and disclose certain clinical trial information. Information related to the product, patient population, phase of investigation, study sites and investigators, and other aspects of the clinical trial is then made public as part of the registration. Sponsors are also obligated to discuss the results of their

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clinical trials after completion. Disclosure of the results of these trials can be delayed in certain circumstances for up to two years after the date of completion of the trial. Competitors may use this publicly available information to gain knowledge regarding the progress of development programs.

Expedited Development and Review Programs

FDA is required to facilitate the development, and expedite the review, of drugs that are intended for the treatment of a serious or life threatening disease or condition for which there is no effective treatment and which demonstrate the potential to address unmet medical needs for the condition.

Fast Track Designation

Fast track designation may be granted for a product that is intended to treat a serious or life-threatening disease or condition for which preclinical or clinical data demonstrate the potential to address unmet medical needs for the condition. The sponsor of an investigational drug product may request that the FDA designate the drug candidate for a specific indication as a fast track drug concurrent with, or after, the submission of the IND for the drug candidate. The FDA must determine if the drug candidate qualifies for fast track designation within 60 days of receipt of the sponsor’s request. For fast track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a fast track product’s NDA before the application is complete. This rolling review is available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a fast track product may be effective. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. At the time of NDA filing, the FDA will determine whether to grant priority review designation. Additionally, fast track designation may be withdrawn if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

Accelerated Approval

Accelerated approval may be granted for a product that is intended to treat a serious or life-threatening condition and that generally provides a meaningful therapeutic advantage to patients over existing treatments. A product eligible for accelerated approval may be approved on the basis of either a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. The accelerated approval pathway is most often used in settings in which the course of a disease is long, and an extended period of time is required to measure the intended clinical benefit of a product, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. The accelerated approval pathway is contingent on a sponsor’s agreement to conduct additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. These confirmatory trials must be completed with due diligence and, in some cases, the FDA may require that the trial be designed, initiated, and/or fully enrolled prior to approval. Failure to conduct required post-approval studies, or to confirm a clinical benefit during post-marketing studies, would allow the FDA to withdraw the product from the market on an expedited basis. All promotional materials for product candidates approved under accelerated regulations are subject to prior review by the FDA.

Orphan Drugs

Under the Orphan Drug Act, the FDA may grant orphan drug designation to drugs intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States but for which there is no reasonable expectation that the cost of developing and making the product for this type of disease or condition will be recovered from sales of the product in the United States.

Orphan drug designation must be requested before submitting an NDA. After the FDA grants orphan drug designation, the identity of the drug and its potential orphan use are disclosed publicly by the FDA. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

The first NDA applicant to receive FDA approval for a particular active moiety to treat a rare disease for which it has such designation is entitled to a seven-year exclusive marketing period in the U.S. for that product, for that indication. During the seven-year exclusivity period, the FDA may not approve any other applications to market the same drug for the same disease, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity by means of greater effectiveness, greater safety, or providing a major contribution to patient care, or in instances of drug supply issues. Orphan drug exclusivity does not prevent the FDA from approving a different drug for the same disease or condition, or the same drug for a different disease or condition. Other benefits of orphan drug designation include tax credits for certain research and an exemption from the NDA user fee.

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Pediatric Information

Under the Pediatric Research Equity Act, or PREA, NDAs or supplements to NDAs must contain data to assess the safety and effectiveness of the drug for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the drug is safe and effective. The FDA may grant full or partial waivers, or deferrals, for submission of data. Unless otherwise required by regulation, PREA does not apply to any drug for an indication for which orphan designation has been granted, with certain exceptions.

The Best Pharmaceuticals for Children Act, or BPCA, provides NDA holders a six-month extension of any exclusivity—patent or nonpatent—for a drug if certain conditions are met. Conditions for exclusivity include the FDA’s determination that information relating to the use of a new drug in the pediatric population may produce health benefits in that population, the FDA making a written request for pediatric studies, and the applicant agreeing to perform, and reporting on, the requested studies within the statutory timeframe. Applications under the BPCA are treated as priority applications, with all of the benefits that designation confers.

Rare Pediatric Disease Vouchers

The Rare Pediatric Disease Voucher Program is intended to encourage development of new drug and biological products for prevention and treatment of certain rare pediatric diseases. Although there are existing incentive programs to encourage the development and study of drugs for rare diseases, pediatric populations, and unmet medical needs, this program provides an additional incentive for the development of drugs for rare pediatric diseases, which may be used alone or in combination with other incentive programs. A rare pediatric disease is defined as a disease that is a serious or life-threatening disease in which the serious or life-threatening manifestations primarily affect individuals aged from birth to 18 years, including age groups often called neonates, infants, children, and adolescents; and is a rare disease or condition as defined in the FD&C Act, which includes diseases and conditions that affect fewer than 200,000 persons in the U.S. and diseases and conditions that affect a larger number of persons and for which there is no reasonable expectation that the costs of developing and making available the drug in the U.S. can be recovered from sales of the drug in the U.S.

The sponsor of a human drug application for a rare pediatric disease drug product may be eligible for a voucher that can be used (or sold) to obtain a priority review for a subsequent human drug application submitted under section 505(b)(1) of the FD&C Act or section 351 of the Public Health Service Act after the date of approval of the rare pediatric disease drug product. The rare pediatric disease priority review voucher program was most recently re-authorized by Congress in the Consolidated Appropriations Act of 2021, extending the rare pediatric disease program through September 30, 2024, with the potential for priority review vouchers to be granted through September 30, 2026.

Post-Approval Requirements

Once an NDA is approved, a product will be subject to certain post-approval requirements. For instance, the FDA closely regulates the post-approval marketing and promotion of drugs, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the internet. Drugs may be marketed only for the approved indications and in a manner consistent with the approved labeling.

Adverse event reporting and submission of periodic reports are required following FDA approval of an NDA. The FDA also may require post-marketing testing, known as phase 4 testing, REMS, and surveillance to monitor the effects of an approved product, or the FDA may place conditions on an approval that could restrict the distribution or use of the product. In addition, quality control, drug manufacture, packaging and labeling procedures must continue to conform to cGMPs after approval. Drug manufacturers and certain of their subcontractors are required to register their establishments with the FDA and certain state agencies. Registration with the FDA subjects entities to periodic unannounced inspections by the FDA, during which the Agency inspects manufacturing facilities to assess compliance with cGMPs. Accordingly, manufacturers must continue to expend time, money and effort in the areas of production and quality-control to maintain compliance with cGMPs. Regulatory authorities may withdraw product approvals or request product recalls if a company fails to comply with regulatory standards, if it encounters problems following initial marketing, or if previously unrecognized problems are subsequently discovered.

The Hatch-Waxman Amendments

Orange Book Listing

Under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch Waxman Amendments, NDA applicants are required to identify to the FDA each patent whose claims cover the applicant’s drug or approved method of using the drug. Upon approval of a drug, the applicant must update its listing of patents to the NDA in timely fashion and

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each of the patents listed in the application for the drug is then published in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book.

Drugs listed in the Orange Book can, in turn, be cited by potential generic competitors in support of approval of an abbreviated new drug application, or ANDA. An ANDA provides for marketing of a drug product that has the same active ingredient(s), strength, route of administration, and dosage form as the listed drug and has been shown through bioequivalence testing to be therapeutically equivalent to the listed drug. An approved ANDA product is considered to be therapeutically equivalent to the listed drug. Other than the requirement for bioequivalence testing, ANDA applicants are not required to conduct, or submit results of, pre-clinical or clinical tests to prove the safety or effectiveness of their drug product. Drugs approved under the ANDA pathway are commonly referred to as “generic equivalents” to the listed drug and can often be substituted by pharmacists under prescriptions written for the original listed drug pursuant to each state’s laws on drug substitution.

The ANDA applicant is required to certify to the FDA concerning any patents identified for the reference listed drug in the Orange Book. Specifically, the applicant must certify to each patent in one of the following ways: (i) the required patent information has not been filed; (ii) the listed patent has expired; (iii) the listed patent has not expired but will expire on a particular date and approval is sought after patent expiration; or (iv) the listed patent is invalid or will not be infringed by the new product. A certification that the new product will not infringe the already approved product’s listed patents, or that such patents are invalid, is called a Paragraph IV certification. For patents listed that claim an approved method of use, under certain circumstances the ANDA applicant may also elect to submit a section viii statement certifying that its proposed ANDA label does not contain (or carves out) any language regarding the patented method-of-use rather than certify to a listed method-of-use patent. If the applicant does not challenge the listed patents through a Paragraph IV certification, the ANDA application will not be approved until all the listed patents claiming the referenced product have expired. If the ANDA applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA-holder and patentee(s) once the ANDA has been accepted for filing by the FDA (referred to as the “notice letter”). The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice letter. The filing of a patent infringement lawsuit within 45 days of the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA until the earlier of 30 months from the date the notice letter is received, expiration of the patent, the date of a settlement order or consent decree signed and entered by the court stating that the patent that is the subject of the certification is invalid or not infringed, or a decision in the patent case that is favorable to the ANDA applicant.

The ANDA application also will not be approved until any applicable non-patent exclusivity listed in the Orange Book for the referenced product has expired. In some instances, an ANDA applicant may receive approval prior to expiration of certain non-patent exclusivity if the applicant seeks, and the FDA permits, the omission of such exclusivity-protected information from the ANDA prescribing information.

Exclusivity

Upon NDA approval of a new chemical entity, or NCE, which is a drug that contains no active moiety that has been approved by the FDA in any other NDA, that drug receives five years of marketing exclusivity during which the FDA cannot receive any ANDA seeking approval of a generic version of that drug unless the application contains a Paragraph IV certification, in which case the application may be submitted one year prior to expiration of the NCE exclusivity. If there is no listed patent in the Orange Book, there may not be a Paragraph IV certification, and, thus, no ANDA for a generic version of the drug may be filed before the expiration of the exclusivity period.

Certain changes to an approved drug, such as the approval of a new indication, the approval of a new strength, and the approval of a new condition of use, are associated with a three-year period of exclusivity from the date of approval during which the FDA cannot approve an ANDA for a generic drug that includes the change. In some instances, an ANDA applicant may receive approval prior to expiration of the three-year exclusivity if the applicant seeks, and the FDA permits, the omission of such exclusivity-protected information from the ANDA package insert.

Patent Term Extension

The Hatch Waxman Amendments permit a patent term extension as compensation for patent term lost during the FDA regulatory review process. Patent term extension, however, cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. After NDA approval, owners of relevant drug patents may apply for the extension. The allowable patent term extension is calculated as half of the drug’s testing phase (the time between IND application and NDA submission) and all of the review phase (the time between NDA submission and approval) up to a maximum of five years. The time can be reduced for any time the FDA determines that the applicant did not pursue approval with due diligence.

The USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. However, the USPTO may not grant an extension because of, for example, failing to exercise due diligence during the testing phase or

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regulatory review process, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the applicable time period or the scope of patent protection afforded could be less than requested.

The total patent term after the extension may not exceed 14 years, and only one patent per product can be extended. The application for the extension must be submitted prior to the expiration of the patent, and for patents that might expire during the application phase, the patent owner may request an interim patent extension. An interim patent extension increases the patent term by one year and may be renewed up to four times. For each interim patent extension granted, the post-approval patent extension is reduced by one year. The director of the USPTO must determine that approval of the drug covered by the patent for which a patent extension is being sought is likely. Interim patent extensions are not available for a drug for which an NDA has not been submitted.

Other Healthcare Laws

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws have been applied to restrict certain general business and marketing practices in the pharmaceutical industry in recent years. These laws include anti-kickback statutes, false claims statutes and other healthcare laws and regulations.

The federal Anti-Kickback Statute prohibits, among other things, persons and entities from knowingly and willfully offering, soliciting or receiving or providing remuneration, directly or indirectly, in cash or in kind, to induce, or in return for, purchasing, leasing, ordering or arranging for the purchase, lease or order of any healthcare item or service reimbursable under Medicare, Medicaid, or other federally financed healthcare programs. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on the one hand and prescribers, purchasers and formulary managers, among others, on the other. Although there are a number of statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution or other regulatory sanctions, the exceptions and safe harbors are drawn narrowly, and practices that involve remuneration intended to induce prescribing, purchases or recommendations may be subject to scrutiny if they do not qualify for an exception or safe harbor. In addition, a person or entity does not need to have actual knowledge of the Anti-Kickback Statute or specific intent to violate it in order to commit a violation.

Federal civil and criminal false claims laws, including the federal civil False Claims Act, prohibit any person or entity from knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making, or causing to be made, a false statement to have a false claim paid. This includes claims made to programs where the federal government reimburses, such as Medicare and Medicaid, as well as programs where the federal government is a direct purchaser, such as when it purchases off the Federal Supply Schedule. Recently, several pharmaceutical and other healthcare companies have been prosecuted under these laws for allegedly inflating drug prices they report to pricing services, which in turn were used by the government to set Medicare and Medicaid reimbursement rates, and for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. In addition, certain marketing practices, including off-label promotion, may also violate false claims laws. Additionally, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act. Most states also have statutes or regulations similar to the federal Anti-Kickback Statute and civil False Claims Act, which apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor.

Other federal statutes pertaining to healthcare fraud and abuse include the civil monetary penalties statute, which prohibits, among other things, the offer or payment of remuneration to a Medicaid or Medicare beneficiary that the offeror or payor knows or should know is likely to influence the beneficiary to order a receive a reimbursable item or service from a particular supplier, and the additional federal criminal statutes created by the Health Insurance Portability and Accountability Act of 1996, or HIPAA, which prohibits, among other things, knowingly and willfully executing or attempting to execute a scheme to defraud any healthcare benefit program or obtain by means of false or fraudulent pretenses, representations or promises of any money or property owned by or under the control of any healthcare benefit program in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to commit a violation.

Further, pursuant to the ACA, the Centers for Medicare & Medicaid Services, or CMS, has issued a final rule that requires manufacturers of prescription drugs to collect and report information on certain payments or transfers of value to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), physician assistants, certain types of advance practice nurses and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members. The reported data is made available in searchable form on a public website on an annual basis. Failure to submit required information may result in civil monetary penalties.

In addition, several states now require prescription drug companies to report certain expenses relating to the marketing and promotion of drug products and to report gifts and payments to individual healthcare practitioners in these states. Other states prohibit various marketing-related activities, such as the provision of certain kinds of gifts or meals. Still other states require the posting of information relating to clinical studies and their outcomes. Some states require the reporting of certain drug pricing information,

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including information pertaining to and justifying price increases. In addition, certain states require pharmaceutical companies to implement compliance programs and/or marketing codes. Certain states and local jurisdictions also require the registration of pharmaceutical sales and medical representatives. Compliance with these laws is difficult and time consuming, and companies that do not comply with these state laws face civil penalties.

Efforts to ensure that business arrangements with third parties comply with applicable healthcare laws and regulations involve substantial costs. If a drug company’s operations are found to be in violation of any such requirements, it may be subject to significant penalties, including civil, criminal and administrative penalties, damages, fines, disgorgement, imprisonment, the curtailment or restructuring of its operations, loss of eligibility to obtain approvals from the FDA, exclusion from participation in government contracting, healthcare reimbursement or other federal or state government healthcare programs, including Medicare and Medicaid, integrity oversight and reporting obligations, imprisonment, and reputational harm. Although effective compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, these risks cannot be entirely eliminated. Any action for an alleged or suspected violation can cause a drug company to incur significant legal expenses and divert management’s attention from the operation of the business, even if such action is successfully defended.

U.S. Healthcare Reform

Healthcare reforms that have been adopted, and that may be adopted in the future, could result in further reductions in coverage and levels of reimbursement for pharmaceutical products, increases in rebates payable under U.S. government rebate programs and additional downward pressure on pharmaceutical product prices.  On September 9, 2021, the Biden administration published a wide-ranging list of policy proposals, most of which would need to be carried out by Congress, to reduce drug prices and drug payment. The Department of Health and Human Services, or HHS, plan includes, among other reform measures, proposals to lower prescription drug prices, including by allowing Medicare to negotiate prices and disincentivizing price increases, and to support market changes that strengthen supply chains, promote biosimilars and generic drugs, and increase price transparency. Many similar proposals, including the plans to give Medicare Part D authority to negotiate drug prices, require drug manufacturers to pay rebates on drugs whose prices increase greater than the rate of inflation, and cap out-of-pocket costs, have already been included in policy statements and legislation currently being considered by Congress. It is unclear to what extent these and other statutory, regulatory, and administrative initiatives will be enacted and implemented.

Data Privacy & Security Laws

Numerous state, federal and foreign laws, including consumer protection laws and regulations, govern the collection, dissemination, use, access to, confidentiality and security of personal information, including health-related information. In the United States, numerous federal and state laws and regulations, including state data breach notification laws, state health information privacy laws, and federal and state consumer protection laws and regulations, govern the collection, use, disclosure, and protection of health-related and other personal information could apply to our operations or the operations of our partners. For example, HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act of 2009, or HITECH, and their respective implementing regulations, imposes privacy, security and breach notification obligations on certain health care providers, health plans, and health care clearinghouses, known as covered entities, as well as their business associates that perform certain services involving creating, receiving, maintaining or transmitting individually identifiable health information for or on behalf of such covered entities.

Even when HIPAA does not apply, according to the Federal Trade Commission, or FTC, violating consumers’ privacy rights or failing to take appropriate steps to keep consumers’ personal information secure may constitute unfair acts or practices in or affecting commerce in violation of Section 5(a) of the Federal Trade Commission Act, or the FTCA, 15 U.S.C § 45(a). The FTC expects a company’s data security measures to be reasonable and appropriate in light of the sensitivity and volume of consumer information it holds, the size and complexity of its business, and the cost of available tools to improve security and reduce vulnerabilities. Individually identifiable health information is considered sensitive data that merits stronger safeguards.

In addition, certain state and non-U.S. laws, notably the California Consumer Privacy Act, or CCPA, the EU’s General Data Protection Regulation, or GDPR, and Canada’s Personal Information Protection and Electronic Documents Act, or PIPEDA, govern the privacy and security of health information in certain circumstances, some of which are more stringent than HIPAA and many of which differ from each other in significant ways and may not have the same effect, thus complicating compliance efforts. Failure to comply with these laws, where applicable, can result in the imposition of significant civil and/or criminal penalties and private litigation. For example, the CCPA, which went into effect January 1, 2020, provides for among other things, new data privacy obligations for covered companies and new privacy rights to California residents, including the right to opt out of certain disclosures of their information. The CCPA also creates a private right of action with statutory damages for certain data breaches, thereby potentially increasing risks associated with a data breach. Colorado and Virginia have also recently enacted comparable consumer privacy regimes set to take effect in 2023, and as of January 2022, fourteen states have pending legislation under review relating to consumer privacy. In Europe, the GDPR went into effect in May 2018 and introduced strict requirements for processing the personal data of individuals within the European Economic Area, or EEA. In addition, the GDPR increases the scrutiny of transfers of personal

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data from clinical trial sites located in the EEA to the United States and other jurisdictions that the European Commission does not recognize as having “adequate” data protection laws, and imposes substantial fines for breaches and violations. In Canada, PIPEDA and similar provincial laws impose obligations on companies with respect to processing personal information, including health-related information. PIPEDA requires companies to obtain an individual’s consent when collecting, using or disclosing that individual’s personal information. Individuals have the right to access and challenge the accuracy of their personal information held by an organization, and personal information may only be used for the purposes for which it was collected. If an organization intends to use personal information for another purpose, it must again obtain that individual’s consent. Failure to comply with PIPEDA could result in significant fines and penalties.

Domestic laws in all 50 states have various thresholds requiring businesses to provide notice to customers whose personally identifiable information was been disclosed as a result of unauthorized access or data breach, in addition to requirements under foreign and federal laws. The laws and respective regulations are not consistent and frequently amended.

Employees and Human Capital Resources

As of December 31, 2021, we had 138 employees, of which 40 held a Ph.D. or M.D. We have not experienced any work stoppages. None of our employees are represented by a labor union or covered by collective bargaining agreements, and we consider our relationship with our employees to be good.

Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and additional employees. The principal purposes of our incentive plans are to attract, retain and motivate selected employees, consultants and directors through the granting of stock-based compensation awards and cash-based performance bonus awards.

Corporate Information

On October 5, 2020, Chinook Therapeutics U.S., Inc. completed its business combination with Aduro Biotech, Inc., a publicly held company. In connection with the Merger, Aduro Biotech, Inc. changed its name to Chinook Therapeutics, Inc. For additional information regarding this business combination, refer to Note 3, “Reverse Merger and Contingent Value Rights” within Part II, Item 8, “Financial Statements and Supplementary Data” in this Annual Report on Form 10-K. Aduro Biotech, Inc. was incorporated in Delaware in June 2011. Chinook Therapeutics U.S., Inc. (prior to its business combination with Aduro Biotech, Inc.) was incorporated in Delaware in November 2018.

Our principal executive offices are located at 400 Fairview Avenue North, Suite 900, Seattle, WA 98109 and our telephone number is (206) 485-7241. Our website address is www.chinooktx.com. Information contained on or accessible through our website is not a part of this Annual Report on Form 10-K. The following filings are available through the SEC, which maintains an Internet site at www.sec.gov, and through our website as soon as reasonably practicable after we file them with the SEC: Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, as well as any amendments to such reports and all other filings pursuant to Section 13(a) or 15 (d) of the Securities Act.

Chinook Therapeutics, the Chinook logo and other trade names, trademarks or service marks of Chinook appearing in this Annual Report on Form 10-K are the property of Chinook. Trade names, trademarks and service marks of other companies appearing in this report are the property of their respective holders.

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Item 1A. Risk Factors.

RISK FACTORS

Investing in our common stock involves a high degree of risk. You should carefully consider the following risks and all of the other information contained in this Annual Report on Form 10-K, including our consolidated financial statements and related notes and the section “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” before investing in our common stock. While we believe that the risks and uncertainties described below are the material risks currently facing us, additional risks that we do not yet know of or that we currently think are immaterial may also arise and materially affect our business. If any of the following risks materialize, our business, financial condition and results of operations could be materially and adversely affected. In that case, the trading price of our common stock could decline, and you may lose some or all of your investment.

Summary of Risk Factors

Our business is subject to a number of risks and uncertainties, including those immediately following this summary. Some of these risks are:

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Risks Related to Our Financial Position

We have a history of operating losses, and may not achieve or sustain profitability. We anticipate that we will continue to incur losses for the foreseeable future. If we fail to obtain additional funding to conduct our planned research and development efforts, we could be forced to delay, reduce or eliminate our product development programs or commercial development efforts.

We are a clinical-stage biotechnology company with a limited operating history. Biotechnology product development is a highly speculative undertaking and involves a substantial degree of risk. Our operations to date have been limited primarily to organizing and staffing the Company, business planning, raising capital, acquiring and developing product and technology rights, manufacturing, and conducting research and development activities for our product candidates. We have never generated any revenue from product sales. We have not obtained regulatory approvals for any of our product candidates and have funded our operations to date through proceeds from sales of preferred stock and common stock.

We have incurred net losses in each year since our inception. We incurred a net loss of $102.9 million for the year ended December 31, 2021. As of December 31, 2021, we had an accumulated deficit of $231.8 million. Substantially all of our operating losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect to continue to incur significant expenses and operating losses over the next several years and for the foreseeable future as we intend to continue to conduct research and development, clinical testing, regulatory compliance activities, manufacturing activities, and, if any of our product candidates are approved, sales and marketing activities that, together with anticipated general and administrative expenses, will likely result in us incurring significant losses for the foreseeable future. Our prior losses, combined with expected future losses, have had and will continue to have an adverse effect on our stockholders’ equity and working capital.

We expect to need to raise additional funding before we become profitable from any potential future sales of atrasentan or our other product candidates. This additional financing may not be available on acceptable terms or at all. Failure to obtain this necessary capital when needed may force us to delay, limit or terminate our product development efforts or other operations.

We will require substantial future capital in order to complete planned and future preclinical and clinical development for atrasentan and other product candidates and potentially commercialize these product candidates. Based upon our current operating plan, we believe that our existing cash, cash equivalents, and marketable securities held as of December 31, 2021 will enable us to fund our operating expenses and capital expenditure requirements for at least the next 24 months. We expect our spending levels to increase in connection with our preclinical studies and clinical trials of our product candidates. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant expenses related to commercial launch, product sales, medical affairs, marketing, manufacturing and distribution. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations before any commercial revenue may occur.

Additional capital might not be available when we need it and our actual cash requirements might be greater than anticipated. If we require additional capital at a time when investment in our industry or in the marketplace in general is limited, we may not be able to raise funding on favorable terms, if at all. If we are not able to obtain financing when needed or on terms favorable to us, we may need to delay, reduce or eliminate certain research and development programs or other operations, sell some or all of our assets or merge with another entity.

Our operations have consumed significant amounts of cash since inception. Our future capital requirements will depend on many factors, including:

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Our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of product candidates that we do not expect to be commercially available for many years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives, which may not be available to us on acceptable terms, or at all.

We have identified material weaknesses in our internal control over financial reporting. Failure to achieve and maintain effective internal control over financial reporting could harm our business and negatively impact the value of our common stock.

We have identified material weaknesses in our internal control over financial reporting. A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis. In preparing our consolidated financial statements as of and for the years ended December 31, 2021 and 2020, our management identified the following material weaknesses in its internal control over financial reporting: (i) we did not design or maintain an effective control environment commensurate with its financial reporting requirements due to lack of sufficient accounting professionals with the appropriate level of skill, experience and training commensurate with its financial reporting requirements. Additionally, the limited personnel resulted in our inability to consistently establish appropriate authorities and responsibilities in pursuit of its financial reporting objectives, as demonstrated by, among other things, insufficient segregation of duties in its finance and accounting functions. This contributed to additional material weaknesses as: (ii) we did not design and maintain formal accounting policies, procedures and controls to achieve complete, accurate and timely financial accounting reporting and disclosures, including controls over the preparation and review of account reconciliations, journal entries and period end financial reporting; and (iii) we did not design and maintain controls over the operating effectiveness of information technology general controls for information systems that are relevant to the preparation of its financial statements. Specifically, we did not design and maintain effective controls over program change management; user access, including segregation of duties; or computer operations.

These material weaknesses could result in adjustments to our consolidated financial statements. Additionally, these material weaknesses could result in a misstatement of our accounts or disclosures that would result in a material misstatement of our future annual or interim financial statements that would not be prevented or detected, and accordingly, we determined that these control deficiencies constitute material weaknesses.

In 2021, we hired additional accounting personnel with appropriate experience, certification, education and training as a component of our plans to remediate the material weaknesses. To the extent that we are not able to retain such individuals, the material weaknesses identified may not be remediated and management may be required to record additional adjustments to our financial statements in the future.

Our internal control over financial reporting may not meet the standards required by Section 404 of the Sarbanes-Oxley Act, and failure to achieve and maintain effective internal control over financial reporting in accordance with Section 404 of the Sarbanes-Oxley Act, could have a material adverse effect on our business and share price.

Our management is required to report on the effectiveness of our internal control over financial reporting. The rules governing the standards that must be met for our management to assess our internal control over financial reporting are complex and require significant documentation, testing and possible remediation.

In preparing our consolidated financial statements as of and for the years ended December 31, 2021 and 2020, we identified material weaknesses in our internal control over financial reporting. We cannot assure you that the material weaknesses identified will be remediated on the timelines currently anticipated by us, or at all, and/or that there will not be additional material weaknesses or significant deficiencies in our internal control over financial reporting in the future. Any failure to maintain effective internal control over financial reporting could severely inhibit our ability to accurately report on our financial condition, results of operations or cash flows. If we are unable to conclude that our internal control over financial reporting is effective, or if our independent registered public accounting firm determines we have a material weakness or significant deficiency in our internal control over financial reporting once that firm begins its reporting on internal control over financial reporting, investors may lose confidence in the accuracy and completeness of our financial reports, the market price of our common stock could decline, and we could be subject to sanctions or investigations by Nasdaq, the SEC or other regulatory authorities. Failure to remedy any material weakness in our internal control over financial reporting, or to implement or maintain other effective control systems required of public companies, could also restrict our future access to the capital markets.

Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future viability.

We are a clinical-stage biotechnology company and our operations to date have been limited to organizing and staffing the Company, business planning, raising capital, acquiring our technology, identifying potential product candidates, undertaking research

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and preclinical studies of our product candidates, manufacturing, and establishing licensing arrangements. We have limited experience in conducting clinical trials and have not yet demonstrated the ability to successfully complete clinical trials of our product candidates, obtain marketing approvals, manufacture a commercial scale product or conduct sales and marketing activities necessary for commercialization. Consequently, any predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history.

Risks Related to Our Product Development and Regulatory Approval

If we are unable to develop, obtain regulatory approval for and commercialize atrasentan or any other future product candidates, or if we experience significant delays in doing so, our business will be materially harmed.

We plan to invest a substantial amount of our efforts and financial resources in our current lead product candidates, atrasentan, an endothelin receptor antagonist, and BION-1301, an anti-APRIL monoclonal antibody. We initiated the ALIGN phase 3 clinical trial of atrasentan, for the treatment of IgAN in March 2021, and in April 2021 we initiated the phase 2 AFFINITY clinical trial for certain proteinuric glomerular diseases. In addition, we are conducting a phase 1/2 clinical trial of BION-1301 for the treatment of IgAN and we presented updated data from this trial at ASN in November 2021. We have submitted an IND and are advancing CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022 for the treatment of PH. We are developing CHK-336 for the treatment of primary hyperoxaluria, as well as secondary hyperoxaluria and idiopathic kidney stone formation, and have received rare pediatric disease designation from the FDA for CHK-336 for the treatment of PH. In addition, we are conducting research programs in several other rare, severe chronic kidney diseases. Our ability to generate product revenue will depend heavily on the successful development and eventual commercialization of atrasentan and our other product candidates, which may never occur. We currently generate no revenue from sales of any product, and we may never be able to develop or commercialize a marketable product.

Each of our programs and product candidates will require further clinical and/or preclinical development, regulatory approval in multiple jurisdictions, obtaining preclinical, clinical and commercial manufacturing supply, capacity and expertise, building of a commercial organization, substantial investment and significant marketing efforts before we generate any revenue from product sales. Atrasentan and our other product candidates must be authorized for marketing by the FDA, the Health Products and Food Branch of Health Canada, or HPFB, the EMA, and certain other foreign regulatory agencies before we may commercialize any of our product candidates.

The success of atrasentan and our other product candidates depends on multiple factors, including:

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If we do not succeed in one or more of these factors in a timely manner or at all, then we could experience significant delays or an inability to successfully commercialize our product candidates, which would materially harm our business. If we do not receive regulatory approvals for our product candidates, we may not be able to continue our operations.

Success in preclinical studies and earlier clinical trials for our product candidates may not be indicative of the results that may be obtained in later clinical trials, including our phase 3 clinical trial for atrasentan, which may delay or prevent obtaining regulatory approval.

Clinical development is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time during the clinical trial process. Success in preclinical studies and early clinical trials may not be predictive of results in later-stage clinical trials, and successful results from early or small clinical trials may not be replicated or show as favorable an outcome in later-stage or larger clinical trials, even if successful. We will be required to demonstrate through adequate and well-controlled clinical trials that our product candidates are safe and effective for their intended uses before we can seek regulatory approvals for their commercial sale. The conduct of phase 3 trials and the submission of an NDA or BLA is a complicated process. We have limited experience in conducting clinical trials and preparing, submitting and supporting regulatory filings, and have not previously submitted an NDA or BLA. Consequently, we may be unable to successfully and efficiently execute and complete necessary clinical trials and other requirements in a way that leads to NDA or BLA submission and approval of any product candidate we are developing.

We in-licensed atrasentan from AbbVie. Atrasentan was previously investigated in a phase 3 clinical trial evaluating the effects of atrasentan on progression of kidney disease in patients with diabetic kidney disease, referred to as the SONAR trial. While patients receiving atrasentan in the SONAR trial had a lower rate of primary composite renal events than patients receiving placebo, the trial accrued measurable primary endpoints at a slower rate than expected, and AbbVie decided to close the study early for corporate strategic reasons. We believe the results of the SONAR trial support further evaluation of atrasentan in IgAN. Although the SONAR trial was not terminated due to safety concerns, further safety issues could be discovered in our phase 3 and phase 2 trials. Based on the data from the SONAR trial, we believe that atrasentan, combined with current standard of care, may have benefits compared to treatment with current standard of care. However, we cannot assure that any potential advantages that we believe atrasentan may have for treatment of patients with proteinuric glomerular diseases will be substantiated by our planned clinical trials or included in the product’s labeling should we obtain approval. Without head-to-head data, we will not be able to make comparative claims with respect to any other treatments. In addition, the patient populations under investigation with atrasentan have many co-morbidities that may cause severe illness or death, which may be attributed to atrasentan in a manner that negatively affects its safety profile. If the results of our clinical trials for atrasentan are inconclusive with respect to efficacy, if we do not meet our clinical endpoints with statistical significance, or if there are unanticipated safety concerns or adverse events that emerge during clinical trials, we may have to conduct further preclinical studies and/or clinical trials before obtaining marketing approval, or we may be prevented from or delayed in obtaining marketing approval.

Though atrasentan has been evaluated by AbbVie in late-stage clinical trials, our other product candidates, such as BION-1301 and CHK-336, have only been evaluated in early-stage clinical trials or have yet to enter clinical trials, and we may experience unexpected or negative results in the future as our other product candidates are evaluated in clinical trials. Any positive results we have observed in preclinical animal models may not be predictive of our future clinical trials in humans, as animal models carry inherent limitations relevant to all preclinical studies. Our product candidates may also fail to show the desired safety and efficacy in later stages of clinical development even if they successfully advance through initial clinical trials. Even if our clinical trials demonstrate acceptable safety and efficacy of atrasentan or our other product candidates and such product candidates receive regulatory approval, the labeling we obtain through negotiations with the FDA or foreign regulatory authorities may not include data on secondary endpoints and may not provide us with a competitive advantage over other products approved for the same or similar indications.

Many companies in the biotechnology industry have suffered significant setbacks in late-stage clinical trials after achieving positive results in early-stage development, and there is a high failure rate for product candidates proceeding through clinical trials. In addition, different methodologies, assumptions and applications we utilize to assess particular safety or efficacy parameters may yield different statistical results. Even if we believe the data collected from clinical trials of our product candidates are promising, these data may not be sufficient to support approval by the FDA or foreign regulatory authorities. Preclinical and clinical data can be interpreted in different ways. Accordingly, the FDA or foreign regulatory authorities could interpret these data in different ways from us or our

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partners, which could delay, limit or prevent regulatory approval. If our study data do not consistently or sufficiently demonstrate the safety or efficacy of any of our product candidates, including atrasentan, to the satisfaction of the FDA or foreign regulatory authorities, then the regulatory approvals for such product candidates could be significantly delayed as we work to meet approval requirements, or, if we are not able to meet these requirements, such approvals could be withheld or withdrawn.

Even if we complete the necessary preclinical studies and clinical trials, we cannot predict when, or if, we will obtain regulatory approval to commercialize a product candidate and the approval may be for a narrower indication than we seek.

Prior to commercialization, atrasentan and our other product candidates must be approved by the FDA pursuant to an NDA or BLA in the United States and pursuant to similar marketing applications by the HPFB, EMA and similar regulatory authorities outside the United States. The process of obtaining marketing approvals, both in the United States and abroad, is expensive and takes many years, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. Failure to obtain marketing approval for a product candidate will prevent us from commercializing the product candidate. We have not received approval to market atrasentan or any of our other product candidates from regulatory authorities in any jurisdiction. We have no experience in submitting and supporting the applications necessary to gain marketing approvals, and, in the event regulatory authorities indicate that we may submit such applications, we may be unable to do so as quickly and efficiently as desired. Securing marketing approval requires the submission of extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. Our product candidates may not be effective, may be only moderately effective or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing approval or prevent or limit commercial use. Regulatory authorities have substantial discretion in the approval process and may refuse to accept or file any application or may decide if our data are insufficient for approval and require additional preclinical, clinical or other studies. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate.

Approval of atrasentan and our other product candidates may be delayed or refused for many reasons, including:

Even if our product candidates meet their pre-specified safety and efficacy endpoints in clinical trials, the regulatory authorities may not complete their review processes in a timely manner and may not consider the clinical trial results sufficient to grant, or we may not be able to obtain, regulatory approval. Additional delays may result if an FDA Advisory Committee or other regulatory authority recommends non-approval or restrictions on approval. In addition, we may experience delays or rejections based upon additional government regulation from future legislation or administrative action, or changes in regulatory authority policy during the period of product development, clinical trials and the review process.

Regulatory authorities also may approve a product candidate for more limited indications than requested or they may impose significant limitations in the form of narrow indications, warnings, contraindications or REMS. These regulatory authorities may also grant approval subject to the performance of costly post-marketing clinical trials. In addition, regulatory authorities may not approve the labeling claims that are necessary or desirable for the successful commercialization of our product candidates. Any of the foregoing scenarios could materially harm the commercial prospects for our product candidates and adversely affect our business, financial condition, results of operations and prospects.

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The COVID-19 pandemic, or similar public health crises, could have a material adverse impact on our business, financial condition and results of operations, including the execution of our clinical trials.

Public health crises such as pandemics or similar outbreaks could adversely impact our business. The measures taken in response to the COVID-19 pandemic have had a significant impact, both direct and indirect, on businesses and commerce, as worker shortages have occurred, supply chains have been disrupted, facilities and production have been suspended, and demand for certain goods and services, such as medical services and supplies, has spiked, while demand for other goods and services, such as travel, has fallen. The extent to which COVID-19 impacts our business and operating results will depend on future developments that are highly uncertain and cannot be accurately predicted, including new information that may emerge concerning COVID-19 and the actions to contain the virus or treat its impact.

For instance, our phase 3 and phase 2 clinical trials of atrasentan and our phase 1/2 clinical trial of BION-1301 have been and may continue to be affected by the pandemic. Site initiation, participant recruitment and enrollment, participant dosing, distribution of clinical trial materials, study monitoring and data analysis for our clinical trials has been and may continue to be delayed due to changes in hospital or university policies, federal, state or local regulations, prioritization of hospital resources toward pandemic efforts, or other reasons related to the pandemic. Additionally, some participants and clinical investigators may not be able to comply with clinical trial protocols. For example, quarantines or other travel limitations (whether voluntary or required) may impede participant movement, affect sponsor access to study sites, or interrupt healthcare services, and we may be unable to conduct our clinical trials. If the global effort to control the spread of COVID-19 and treat COVID-19 patients continues on the current trajectory for an extended period of time, we risk a delay in activating sites and enrolling subjects as previously projected. Any such delays in our phase 3 ALIGN clinical trial for atrasentan and the clinical trials for our other product candidates could impact the use and sufficiency of our existing cash reserves, and we may be required to raise additional capital earlier than we had previously planned. We may be unable to raise additional capital if and when needed, which may result in further delays or suspension of our development plans.

Further, infections and deaths related to COVID-19 are disrupting certain healthcare and healthcare regulatory systems globally. Such disruptions could divert healthcare resources away from, or materially delay review by, the FDA and comparable foreign regulatory agencies. It is unknown how long these disruptions could continue, were they to occur. Any elongation or de-prioritization of our clinical trials or delay in regulatory review resulting from such disruptions could materially adversely affect the development and study of our product candidates.

We currently utilize third parties to, among other things, manufacture raw materials and our product candidates, components, parts, and consumables, and to perform quality testing. If either we or any third-party in the supply chain for materials used in the production of our product candidates are adversely impacted by restrictions resulting from the COVID-19 pandemic, our supply chain may be disrupted, limiting our ability to manufacture product candidates for our clinical trials.

In response to the COVID-19 pandemic, we have at times limited access to our offices and have undertaken safety precautions to reduce the risk of transmission in our workforce. Due to mandated local travel restrictions, such as quarantine requirements, third parties conducting clinical or manufacturing activities may not be able to access laboratory or manufacturing space, and our core activities may be significantly limited or curtailed, possibly for an extended period of time.

The spread of COVID-19, which has caused a broad impact globally, including restrictions on travel and quarantine policies put into place by businesses and governments, may have a material adverse effect on our business. While the potential economic impact brought by and the duration of the pandemic may be difficult to assess or predict, it has already caused, and is likely to result in further, significant disruption of global financial markets and the trading prices of biopharmaceutical companies have been highly volatile as a result of the COVID-19 pandemic, which may reduce our ability to access capital either at all or on favorable terms. In addition, a recession, depression or other sustained adverse market event resulting from the global effort to control COVID-19 infections could materially and adversely affect our business.

The ultimate impact of the current pandemic, or any other health epidemic, is highly uncertain and subject to change. We do not yet know the full extent of potential delays or impacts on the Company’s business, our planned clinical trials, healthcare systems or the global economy as a whole. However, these effects could have a material adverse impact on our business, financial condition and results of operations.

Atrasentan and our other product candidates may cause undesirable and/or unforeseen side effects or be perceived by the public as unsafe, which could delay or prevent their advancement into clinical trials or regulatory approval, limit the commercial potential or result in significant negative consequences.

As is the case with pharmaceuticals generally, it is likely that there may be side effects and adverse events associated with our product candidates’ use. For example, in the phase 3 SONAR trial, the most common adverse events of atrasentan included fluid retention and anemia. Results of our clinical trials could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics. If any such adverse events occur, our clinical trials could be suspended or terminated and the FDA, the

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HPFB, the European Commission, the EMA or other regulatory authorities could order us to cease further development of, or deny approval of, our product candidates for any or all targeted indications. Even if we can demonstrate that all future serious adverse events are not product-related, such occurrences could affect patient recruitment or the ability of enrolled patients to complete the trial. Moreover, if we elect, or are required, to not initiate, delay, suspend or terminate any future clinical trial of any of our product candidates, the commercial prospects of such product candidates may be harmed and our ability to generate product revenues from any of these product candidates may be delayed or eliminated. Any of these occurrences may harm our ability to develop other product candidates, and may adversely affect our business, financial condition, results of operations and prospects significantly. Other treatments for kidney diseases that utilize an ET_A receptor antagonist or similar mechanism of action could also generate data that could adversely affect the clinical, regulatory or commercial perception of atrasentan and our other product candidates.

Additionally, if any of our product candidates receives marketing approval, the FDA could require us to adopt a REMS to ensure that the benefits of the product outweigh its risks, which may include, for example, a Medication Guide outlining the risks of the product for distribution to patients and a communication plan to health care practitioners, or other elements to assure safe use of the product. For example, other approved ERAs have been required to include a REMS for women of child-bearing age regarding the risk of embryo-fetal toxicity. Furthermore, if we or others later identify undesirable side effects caused by our product candidates, several potentially significant negative consequences could result, including:

Any of these occurrences may harm our business, financial condition, results of operations and prospects significantly.

Certain of the diseases we seek to treat have low prevalence, and it may be difficult to identify patients with these diseases, which may lead to delays in enrollment for our trials or slower commercial revenue growth if atrasentan or our other product candidates are approved.

While chronic kidney diseases represent a large market, primary glomerular kidney diseases, including IgAN, to which our lead product candidate is targeted, have relatively low incidence and prevalence. We estimate that IgAN affects approximately 140,000 – 150,000 patients in the United States, approximately 200,000 people in Europe and several million people in Asia. We are also developing CHK-336 for the treatment of primary hyperoxaluria, which is an ultra orphan disease with an even smaller number of patients. Small target patient populations could pose obstacles to the timely recruitment and enrollment of a sufficient number of eligible patients in our trials, or limit a product candidate’s commercial potential. Patient enrollment may be affected by other factors including:

Our inability to enroll a sufficient number of patients with these diseases for our clinical trials would result in significant delays and could cause us to not initiate or abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may result in increased time to potential approval and development costs for our product candidates, which would cause the value of the Company to decline and limit our ability to obtain additional financing.

Additionally, our projections of both the number of people who have IgAN and other proteinuric glomerular diseases, as well as the people with these diseases who have the potential to benefit from treatment with our product candidates, are based on estimates derived from a commissioned market research study, which may not accurately identify the size of the market for our product candidates. The total addressable market opportunity for atrasentan and our other product candidates will ultimately depend upon, among other things, the final labeling for our product candidates, if our product candidates are approved for sale in our target

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indications, acceptance by the medical community and patient access, drug pricing and reimbursement. The number of patients globally may turn out to be lower than expected, patients may not be otherwise amenable to treatment with our product candidates, or new patients may become increasingly difficult to identify or gain access to, all of which would adversely affect our results of operations and our business.

Moreover, in light of the limited number of potential patients impacted by proteinuric glomerular diseases, our per-patient therapy pricing of atrasentan, if approved, may need to be high in order to recover our development and manufacturing costs, fund additional research and achieve profitability. We may also need to fund patient support programs upon the marketing of a product candidate, which would negatively affect our product revenue. We may be unable to maintain or obtain sufficient therapy sales volumes at a price high enough to justify our development efforts and our sales, marketing and manufacturing expenses.

We may not be successful in our efforts to expand our pipeline of product candidates and develop marketable products.

Because we have limited financial and managerial resources, we focus on research programs and product candidates that we identify for specific indications. Our business depends on our successful development and commercialization of the limited number of internal product candidates we are researching or have in preclinical development. Even if we are successful in continuing to build our pipeline, development of the potential product candidates that we identify will require substantial investment in additional clinical development, management of clinical, preclinical and manufacturing activities, regulatory approval in multiple jurisdictions, obtaining manufacturing supply capability, building a commercial organization, and significant marketing efforts before we generate any revenue from product sales. Furthermore, such product candidates may not be suitable for clinical development, including as a result of their harmful side effects, limited efficacy or other characteristics that indicate that they are unlikely to be products that will receive marketing approval and achieve market acceptance. If we cannot develop further product candidates, we may not be able to obtain product revenue in future periods, which would adversely affect our business, prospects, financial condition and results of operations.

Although our pipeline includes multiple programs, we are primarily focused on our lead product candidates, atrasentan, BION-1301 and CHK-336, and we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities and our spending on current and future research and development programs and product candidates for specific indications may not yield any commercially viable products. Our understanding and evaluation of biological targets for the discovery and development of new product candidates may fail to identify challenges encountered in subsequent preclinical and clinical development. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights.

Any product candidate for which we obtain marketing approval will be subject to extensive post-marketing regulatory requirements and could be subject to post-marketing restrictions or withdrawal from the market, and we may be subject to penalties if it fails to comply with regulatory requirements or if it experiences unanticipated problems with our product candidates, when and if any of them are approved.

Our product candidates and the activities associated with their development and potential commercialization, including their testing, manufacturing, recordkeeping, labeling, storage, approval, advertising, promotion, sale and distribution, are subject to comprehensive regulation by the FDA and other U.S. and international regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports, registration and listing requirements, requirements relating to manufacturing, including current Good Manufacturing Practices, or cGMPs, quality control, quality assurance and corresponding maintenance of records and documents, including periodic inspections by the FDA and other regulatory authorities and requirements regarding the distribution of samples to providers and recordkeeping. In addition, manufacturers of drug products and their facilities are subject to continual review and periodic, unannounced inspections by the FDA and other regulatory authorities for compliance with cGMPs.

The FDA may also impose requirements for costly post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of any approved product. The FDA closely regulates the post-approval marketing and promotion of drugs to ensure that they are marketed in a manner consistent with the provisions of the approved labeling. The FDA imposes stringent restrictions on manufacturers’ communications regarding use of their products. If we promote our product candidates in a manner inconsistent with FDA-approved labeling or otherwise not in compliance with FDA regulations, we may be subject to enforcement action. Violations of the FD&C Act relating to the promotion of prescription drugs may lead to investigations alleging violations of federal and state healthcare fraud and abuse laws, as well as state consumer protection laws and similar laws in international jurisdictions.

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In addition, later discovery of previously unknown adverse events or other problems with our product candidates, manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may yield various results, including:

The occurrence of any event or penalty described above may inhibit our ability to commercialize our product candidates and generate revenue and could require us to expend significant time and resources in response and could generate negative publicity. The FDA’s and other regulatory authorities’ policies may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we have obtained, and we may not achieve or sustain profitability.

Non-compliance with Canadian and European requirements regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, can also result in significant financial penalties. Similarly, failure to comply with Canada’s or Europe’s requirements regarding the protection of personal information can also lead to significant penalties and sanctions.

Our failure to obtain regulatory approval in international jurisdictions would prevent us from marketing our product candidates outside the United States.

To market and sell atrasentan and our other product candidates in other jurisdictions, we must obtain separate marketing approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among countries and can involve additional testing. The time and data required to obtain approval may differ substantially from that required to obtain FDA approval. The regulatory approval process outside the United States generally includes all the risks associated with obtaining FDA approval. In addition, in many countries outside the United States, we must secure product reimbursement approvals before regulatory authorities will approve the product for sale in that country. Failure to obtain foreign regulatory approvals or non-compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of our product candidates in certain countries.

If we fail to comply with the regulatory requirements in international markets and receive applicable marketing approvals, our target market will be reduced and our ability to realize the full market potential of our product candidates will be harmed and our business will be adversely affected. We may not obtain foreign regulatory approvals on a timely basis, if at all. Our failure to obtain approval of any of our product candidates by regulatory authorities in another country may significantly diminish the commercial prospects of that product candidate and our business prospects could decline.

Risks Related to Commercialization and Manufacturing

The commercial success of our product candidates, including atrasentan, will depend upon their degree of market acceptance by providers, patients, patient advocacy groups, third-party payors and the general medical community.

Even with the requisite approvals from the FDA, the HPFB, the EMA and other regulatory authorities internationally, the commercial success of our product candidates will depend, in part, on the acceptance of providers, patients and third-party payors of drugs designed to act as a selective blocker of the ET_A receptor in particular for atrasentan, and our product candidates in general, as

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medically necessary, cost-effective and safe. In addition, we may face challenges in seeking to establish and grow sales of atrasentan or our other product candidates. Any product that we commercialize may not gain acceptance by providers, patients, patient advocacy groups, third-party payors and the general medical community. If these products do not achieve an adequate level of acceptance, we may not generate significant product revenue and may not become profitable. The degree of market acceptance of atrasentan and our other product candidates, if approved for commercial sale, will depend on several factors, including:

Even if a potential product displays a favorable efficacy and safety profile in preclinical studies and clinical trials, market acceptance of the product will not be fully known until after it is launched.

The pricing, insurance coverage and reimbursement status of newly approved products is uncertain. Failure to obtain or maintain adequate coverage and reimbursement for our product candidates, if approved, could limit our ability to market those products and decrease our ability to generate product revenue.

Our target indications, including IgAN and other proteinuric glomerular diseases, are indications with relatively small patient populations. For product candidates that are designed to treat smaller patient populations to be commercially viable, the reimbursement for such product candidates must be higher, on a relative basis, to account for the lack of volume. Accordingly, we will need to implement a coverage and reimbursement strategy for any approved product candidate that accounts for the smaller potential market size. If we are unable to establish or sustain coverage and adequate reimbursement for our product candidates from third-party payors, the adoption of those product candidates and sales revenue will be adversely affected, which, in turn, could adversely affect the ability to market or sell those product candidates, if approved.

We expect that coverage and reimbursement by third-party payors will be essential for most patients to be able to afford these treatments. Accordingly, sales of atrasentan and our other product candidates will depend substantially, both domestically and internationally, on the extent to which the costs of our product candidates will be paid by health maintenance, managed care, pharmacy benefit and similar healthcare management organizations, or will be reimbursed by government authorities, private health coverage insurers and other third-party payors. Even if coverage is provided, the approved reimbursement amount may not be high enough to allow us to establish or maintain pricing sufficient to realize a sufficient return on our investment.

There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In the United States, third-party payors, including private and governmental payors, such as the Medicare and Medicaid programs, play an important role in determining the extent to which new drugs will be covered and reimbursed. The Medicare program covers certain individuals aged 65 or older, disabled or suffering from end-stage kidney disease. The Medicaid program, which varies from state-to-state, covers certain individuals and families who have limited financial means. The Medicare and Medicaid programs increasingly are used as models for how private payors and other governmental payors develop their coverage and reimbursement policies for drugs. One payor’s determination to provide coverage for a drug product, however, does not assure that other payors will also provide coverage for the drug product. Further, a payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved.

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In addition to government and private payors, professional organizations such as the American Medical Association, or the AMA, can influence decisions about coverage and reimbursement for new products by determining standards for care. In addition, many private payors contract with commercial vendors who sell software that provide guidelines that attempt to limit utilization of, and therefore reimbursement for, certain products deemed to provide limited benefit to existing alternatives. Such organizations may set guidelines that limit reimbursement or utilization of our product candidates. Even if favorable coverage and reimbursement status is attained for one or more product candidates for which our collaborators receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Outside the United States, international operations are generally subject to extensive governmental price controls and other market regulations, and we believe the increasing emphasis on cost-containment initiatives in Europe, Canada and other countries has and will continue to put pressure on the pricing and usage of therapeutics such as our product candidates. In many countries, particularly the countries of the EU, the prices of medical products are subject to varying price control mechanisms as part of national health systems. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. In general, the prices of products under such systems are substantially lower than in the United States. Other countries allow companies to fix their own prices for products, but monitor and control company profits. Additional foreign price controls or other changes in pricing regulation could restrict the amount that we are able to charge for our product candidates. Accordingly, in markets outside the United States, the reimbursement for our product candidates may be reduced compared with the United States and may be insufficient to generate commercially reasonable revenues and profits.

Moreover, increasing efforts by governmental and third-party payors, in the United States and internationally, to cap or reduce healthcare costs may cause such organizations to limit both coverage and level of reimbursement for new products approved and, as a result, they may not cover or provide adequate payment for our product candidates. We expect to experience pricing pressures in connection with the sale of any of our product candidates due to the trend toward managed healthcare, the increasing influence of certain third-party payors, such as health maintenance organizations, and additional legislative changes. The downward pressure on healthcare costs in general, particularly prescription drugs and surgical procedures and other treatments, has become very intense. As a result, increasingly high barriers are being erected to the entry of new products into the healthcare market. Recently there have been instances in which third-party payors have refused to reimburse treatments for patients for whom the treatment is indicated in the FDA-approved product labeling. Even if we are successful in obtaining FDA approvals to commercialize our product candidates, we cannot guarantee that we will be able to secure reimbursement for all patients for whom treatment with our product candidates is indicated.

If third parties on which we depend to conduct our preclinical studies or clinical trials, do not perform as contractually required, fail to satisfy regulatory or legal requirements or miss expected deadlines, our development program could be delayed with adverse effects on our business, financial condition, results of operations and prospects.

We rely on third party CROs, CMOs, consultants and others to design, conduct, supervise and monitor key activities relating to, discovery, manufacturing, preclinical studies and clinical trials of our product candidates, and we intend to do the same for future activities relating to existing and future programs. Because we rely on third parties and do not have the ability to conduct all required testing, discovery, manufacturing, preclinical studies or clinical trials independently, we have less control over the timing, quality and other aspects of discovery, manufacturing, preclinical studies and clinical trials than we would if we conducted them on our own. These investigators, CROs, CMOs and consultants are not our employees, and we have limited control over the amount of time and resources that they dedicate in our programs. These third parties may have contractual relationships with other entities, some of which may be our competitors, which may draw time and resources from our programs. The third parties we contract with might not be diligent, careful or timely in conducting our discovery, manufacturing, preclinical studies or clinical trials, resulting in testing, discovery, manufacturing, preclinical studies or clinical trials being delayed or unsuccessful, in whole or in part.

If we cannot contract with acceptable third parties on commercially reasonable terms, or at all, or if these third parties do not carry out their contractual duties, satisfy legal and regulatory requirements for the conduct of preclinical studies or clinical trials or meet expected deadlines, our clinical development programs could be delayed and otherwise adversely affected. In all events, we are responsible for ensuring that each of our preclinical studies and clinical trials is conducted in accordance with the general investigational plan and protocols for the trial, as well as in accordance with GLP, GCP and other applicable laws, regulations and standards. Our reliance on third parties that we do not control does not relieve us of these responsibilities and requirements. The FDA and other regulatory authorities enforce GCPs through periodic inspections of trial sponsors, principal investigators and trial sites. If the Company or any of these third parties fails to comply with applicable GCPs, the clinical data generated in our clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials have complied with GCPs. In addition, our clinical trials must be conducted with product produced in accordance with cGMPs. Our failure to comply with these regulations may require us to repeat clinical trials,

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which could delay or prevent the receipt of regulatory approvals. Any such event could have an adverse effect on our business, financial condition, results of operations and prospects.

We face significant competition in an environment of rapid technological change and it is possible that our competitors may achieve regulatory approval before us or develop therapies that are more advanced or effective than ours, which may harm our business, financial condition and our ability to successfully market or commercialize atrasentan and our other product candidates.

The biotechnology and pharmaceutical industries are characterized by rapidly changing technologies, competition and a strong emphasis on intellectual property. We are aware of several companies focused on developing proteinuric glomerular disease treatments in various indications as well as several companies addressing other treatments for rare, severe chronic kidney diseases. We may also face competition from large and specialty pharmaceutical and biotechnology companies, academic research institutions, government agencies and public and private research institutions that conduct research, seek patent protection, and establish collaborative arrangements for research, development, manufacturing and commercialization.

Although several companies are focused on developing treatments on IgAN and other proteinuric glomerular diseases, there are currently limited treatment options for proteinuric glomerular diseases. To our knowledge, there is one approved drug for IgAN, as well as a variety of additional treatments utilized that include renin angiotensin inhibitors, steroids, chemotherapy drugs and immunomodulatory approaches. In addition, there are a number of competitors in clinical development for the treatment of IgAN at a similar stage of development or more advanced than us, including AstraZeneca PLC, Novartis AG, Omeros Corporation, Reata Pharmaceuticals, Inc., Travere Therapeutics, Inc., Vera Therapeutics, Inc., and Otsuka Pharmaceutical Co., Ltd.

Many of our potential competitors, alone or with their strategic partners, may have substantially greater financial, technical and other resources than we do, such as larger research and development, clinical, marketing and manufacturing organizations. Mergers and acquisitions in the biotechnology and pharmaceutical industries may result in even more resources being concentrated among a smaller number of competitors. Our commercial opportunity could be reduced or eliminated if competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any product candidates that we may develop. Competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for our products, which could result in our competitors establishing a strong market position before we are able to enter the market, if ever. Additionally, new or advanced technologies developed by our competitors may render our current or future product candidates uneconomical or obsolete, and we may not be successful in marketing our product candidates against competitors.

To become and remain profitable, we must develop and eventually commercialize product candidates with significant market potential, which will require us to be successful in a range of challenging activities. These activities include, among other things, completing preclinical studies and initiating and completing clinical trials of our product candidates, obtaining marketing approval for these product candidates, manufacturing, marketing and selling those products that are approved and satisfying any post marketing requirements. We may never succeed in any or all of these activities and, even if we do, we may never generate revenues that are significant or large enough to achieve profitability. If we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would decrease the value of the company and could impair our ability to raise capital, maintain our research and development efforts, expand our business or continue operations. A decline in the value of the Company also could cause you to lose all or part of your investment.

The manufacture of drugs is complex, and our third-party manufacturers may encounter difficulties in production. If any of our third-party manufacturers encounter such difficulties, our ability to provide supply of atrasentan or our other product candidates for clinical trials, our ability to obtain marketing approval, or our ability to provide supply of our product candidates for patients, if approved, could be delayed or stopped.

We intend to establish manufacturing relationships with a limited number of suppliers to manufacture raw materials, the drug substance and finished product of any product candidate for which we are responsible for preclinical or clinical development. Pursuant to our license agreement with AbbVie, we received a substantial amount of drug product and drug substance to support initiation of our clinical trials of atrasentan; however, we do not yet have a long-term commercial manufacturing agreement for atrasentan with AbbVie or any other CMO. We will need to establish manufacturing relationships for the production of sufficient atrasentan for any potential commercialization. Each supplier may require licenses to manufacture such components if such processes are not owned by the supplier or in the public domain. As part of any marketing approval, a manufacturer and our processes are required to be qualified by the FDA prior to regulatory approval. If supply from the approved vendor is interrupted, there could be a significant disruption in commercial supply. An alternative vendor would need to be qualified through an NDA supplement which could result in further delay. The FDA or other regulatory agencies outside of the United States may also require additional studies if a new supplier is relied upon for commercial production. Switching vendors may involve substantial costs and is likely to result in a delay in our desired clinical and commercial timelines.

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The process of manufacturing drugs is complex, highly-regulated and subject to multiple risks. Manufacturing drugs is highly susceptible to product loss due to contamination, equipment failure, improper installation or operation of equipment, vendor or operator error, inconsistency in yields, variability in product characteristics and difficulties in scaling the production process. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects and other supply disruptions. If microbial, viral or other contaminations are discovered at the facilities of our manufacturers, such facilities may need to be closed for an extended period of time to investigate and remedy the contamination, which could delay clinical trials and adversely harm our business. Moreover, if the FDA determines that our CMOs are not in compliance with FDA laws and regulations, including those governing cGMPs, the FDA may deny regulatory approval until the deficiencies are corrected or we replace the manufacturer in our regulatory approvals with a manufacturer that is in compliance. In addition, approved products and the facilities at which they are manufactured are required to maintain ongoing compliance with extensive FDA requirements and the requirements of other similar agencies, including ensuring that quality control and manufacturing procedures conform to cGMP requirements. As such, our CMOs are subject to continual review and periodic inspections to assess compliance with cGMPs. Furthermore, although we do not have day-to-day control over the operations of our CMOs, we are responsible for ensuring compliance with applicable laws and regulations, including cGMPs.

In addition, there are risks associated with large scale manufacturing for clinical trials or commercial scale including, among others, cost overruns, potential problems with process scale-up, process reproducibility, stability issues, compliance with good manufacturing practices, lot consistency and timely availability of raw materials. Even if our collaborators obtain regulatory approval for any of our product candidates, there is no assurance that manufacturers will be able to manufacture the approved product to specifications acceptable to the FDA or other regulatory authorities, to produce it in sufficient quantities to meet the requirements for the potential launch of the product or to meet potential future demand. If our manufacturers are unable to produce sufficient quantities for clinical trials or meet potential future demand. If our manufacturers are unable to produce sufficient quantities for clinical trials or for commercialization, commercialization efforts would be impaired, which would have an adverse effect on our business, financial condition, results of operations and prospects.

We believe that we will rely upon a limited number of manufacturers for our product candidates, including atrasentan, for which we have identified single-source suppliers for the various steps of manufacture. This reliance on a limited number of manufacturers and the complexity of drug manufacturing and the difficulty of scaling up a manufacturing process could cause the delay of clinical trials, regulatory submissions, required approvals or commercialization of our product candidates, cause us to incur higher costs and prevent us from commercializing our product candidates successfully. Furthermore, if our suppliers fail to deliver the required commercial quantities of materials on a timely basis and at commercially reasonable prices, and we are unable to secure one or more replacement suppliers capable of production in a timely manner at a substantially equivalent cost, our clinical trials may be delayed or we could lose potential revenue.

If we are unable to establish sales and marketing capabilities or enter into agreements with third parties to market and sell atrasentan and our other product candidates, we may be unable to generate any revenues.

We currently do not have an organization for the sales, marketing and distribution of atrasentan, BION-1301, CHK-336 and our other product candidates, and the expense of establishing and maintaining such an organization may exceed the cost-effectiveness of doing so. To market any products that may be approved, we must build our sales, marketing, managerial and other non-technical capabilities or make arrangements with third parties to perform these services. With respect to certain of our current programs as well as future programs, we may rely completely on an alliance partner for sales and marketing. In addition, although we intend to establish a sales organization if we are able to obtain approval to market any product candidates, we may enter into strategic alliances with third parties to develop and commercialize atrasentan and other product candidates, including in markets outside of the United States or for other large markets that are beyond our resources, such as the joint venture, SanReno Therapeutics, we formed in late 2021 for the development and commercialization of atrasentan and BION-1301 in China and certain other East-Asian countries. This will reduce the revenue generated from the sales of these products.

Any future strategic alliance partners may not dedicate sufficient resources to the commercialization of our product candidates or may otherwise fail in their commercialization due to factors beyond our control. If we are unable to establish effective alliances to enable the sale of our product candidates to healthcare professionals and in geographical regions, including the United States, that will not be covered by our marketing and sales force, or if our potential future strategic alliance partners do not successfully commercialize the product candidates, our ability to generate revenues from product sales will be adversely affected.

If we are unable to establish adequate sales, marketing and distribution capabilities, whether independently or with third parties, we may not be able to generate sufficient product revenue and may not become profitable. We will be competing with many companies that currently have extensive and well-funded marketing and sales operations. Without an internal team or the support of a third party to perform marketing and sales functions, we may be unable to compete successfully against these more established companies.

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We may not be successful in finding strategic collaborators for continuing development of certain of our future product candidates or successfully commercializing or competing in the market for certain indications.

In the future, we may decide to collaborate with non-profit organizations, universities and pharmaceutical and biotechnology companies for the development and potential commercialization of existing and new product candidates. We face significant competition in seeking appropriate collaborators. Whether we reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Those factors may include the design or results of clinical trials, the likelihood of approval by the FDA or similar regulatory authorities outside the United States, the potential market for the subject product candidate, the costs and complexities of manufacturing and delivering such product candidate to patients, the potential of competing drugs, the existence of uncertainty with respect to our ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge and industry and market conditions generally. The collaborator may also consider alternative product candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us for our product candidate. The terms of any additional collaborations or other arrangements that we may establish may not be favorable to us. Collaborations are complex and time-consuming to negotiate and document. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators.

We may not be able to negotiate collaborations on a timely basis, on acceptable terms, or at all. If we are unable to do so, we may have to curtail the development of the product candidate for which we are seeking to collaborate, reduce or delay our development program or one or more of our other development programs, delay our potential commercialization or reduce the scope of any sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our expense. If we elect to increase our expenditures to fund development or commercialization activities on our product candidates, we may need to obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we may not be able to further develop our product candidates or bring them to market and generate product revenue.

The success of any potential collaboration arrangements will depend heavily on the efforts and activities of our collaborators. Collaborators generally have significant discretion in determining the efforts and resources that they will apply to these collaborations. Disagreements between parties to a collaboration arrangement regarding clinical development and commercialization matters can lead to delays in the development process or commercializing the applicable product candidate and, in some cases, termination of such collaboration arrangements. These disagreements can be difficult to resolve if neither of the parties has final decision-making authority. Collaborations with pharmaceutical or biotechnology companies and other third parties often are terminated or allowed to expire by the other party. Any such termination or expiration would adversely affect us financially and could harm our business reputation.

Risks Related to Government Regulation

A Fast Track Designation by the FDA, even if granted for any of our product candidates, may not lead to a faster development or regulatory review or approval process, and does not increase the likelihood that our product candidates will receive marketing approval.

While we do not intend to seek Fast Track Designation for atrasentan, we may seek such designation for our other product candidates. If a drug is intended for the treatment of a serious or life-threatening condition and the drug demonstrates the potential to address unmet medical needs for this condition, the drug sponsor may apply to the FDA for Fast Track Designation. The FDA has broad discretion whether to grant this designation. Even if we believe a particular product candidate is eligible for this designation, we cannot assure you that the FDA would decide to grant it. The FDA may also withdraw Fast Track Designation if it believes that the designation is no longer supported by data from our clinical development program. Even if we receive Fast Track Designation for any of our product candidates, such product candidates may not experience faster development, review or approval processes compared to conventional FDA procedures. Many drugs that have received Fast Track Designation have failed to obtain approval.

We may attempt to secure FDA approval of atrasentan and our other product candidates through the accelerated approval pathway. If we are unable to obtain accelerated approval, we may be required to conduct additional clinical trials beyond those that we currently contemplate, which could increase the expense of obtaining, and delay the receipt of, necessary marketing approvals.

We are developing certain product candidates for the treatment of serious conditions, and therefore may decide to seek approval of such product candidates under the FDA’s accelerated approval pathway. A product may be eligible for accelerated approval if it is designed to treat a serious or life-threatening disease or condition and provides a meaningful therapeutic benefit over existing treatments based upon a determination that the product candidate has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability of or lack of alternative treatments. For the purposes of accelerated approval, a

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surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit.

The accelerated approval pathway may be used in cases in which the advantage of a new drug over available therapy may not be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. If granted, accelerated approval is usually contingent on the sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the drug’s anticipated effect on irreversible morbidity or mortality or other clinical benefit. In some cases, the FDA may require that the trial be designed, initiated, and/or fully enrolled prior to approval. If the sponsor fails to conduct such studies in a timely manner, or if such post-approval studies fail to verify the drug’s predicted clinical benefit, or if other evidence demonstrates that the product candidate is not shown to be safe and effective under the conditions of use, the FDA may withdraw its approval of the drug on an expedited basis.

We intend to use reduction in proteinuria as a surrogate endpoint in our phase 3 ALIGN trial of atrasentan. However, atrasentan may not show a sufficient treatment benefit on the expected surrogate endpoint to satisfy the FDA that the anticipated benefit on loss of renal function will be confirmed in the planned post-marketing phase of the trial. If we decide to submit an NDA seeking accelerated approval or receive an expedited regulatory designation for atrasentan or any of our other product candidates, there can be no assurance that such submission or application will be accepted or that any expedited development, review or approval will be granted on a timely basis, or at all. If any of our competitors were to receive full approval for an indication for which we are seeking accelerated approval before we receive accelerated approval, the indication we are seeking may no longer qualify as a condition for which there is an unmet medical need and accelerated approval of our product candidate would be more difficult or may not occur.

Recently, the accelerated approval pathway has come under scrutiny within the FDA and by Congress. The FDA has put increased focus on ensuring that confirmatory studies are conducted with diligence and, ultimately, that such studies confirm the benefit. In addition, Congress is considering various proposals to potentially make changes to the accelerated approval pathway, including proposals to increase the likelihood of withdrawal of approval in such circumstances.

Failure to obtain accelerated approval or any other form of expedited development, review or approval for our product candidates would result in a longer time period to commercialization of such product candidate, if any, and could increase the cost of development of such product candidate and harm our competitive position in the marketplace.

We may be unsuccessful in obtaining Orphan Drug Designation for our product candidates or transfer of designations obtained by others for future product candidates, and, even if we obtain such designation, we may be unable to maintain the benefits associated with Orphan Drug Designation, including the potential for market exclusivity, for atrasentan or our other product candidates.

Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs intended to treat relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a drug as an orphan drug if it is intended to treat a rare disease or condition, which is defined as a patient population of fewer than 200,000 individuals in the United States, or a patient population greater than 200,000 in the United States when there is no reasonable expectation that the cost of developing and making available the drug in the United States will be recovered from sales in the United States for that drug. Orphan drug designation must be requested before submitting for regulatory approval. In the United States, Orphan Drug Designation entitles a party to financial incentives such as opportunities for tax credits for qualified clinical research costs and exemption from prescription drug user fees. Similarly, in the EU, the European Commission grants Orphan Drug Designation after receiving the opinion of the EMA’s Committee for Orphan Medicinal Products on an Orphan Drug Designation application. In the EU, Orphan Drug Designation is intended to promote the development of drugs that are intended for the diagnosis, prevention or treatment of life-threatening or chronically debilitating conditions affecting not more than five in 10,000 persons in the EU and for which no satisfactory method of diagnosis, prevention or treatment has been authorized (or the product would be a significant benefit to those affected). In the EU, Orphan Drug Designation entitles a party to financial incentives such as reduction of fees or fee waivers.

Generally, if a drug with an Orphan Drug Designation subsequently receives the first marketing approval for the indication for which it has such designation, the drug is entitled to a period of marketing exclusivity, which precludes the FDA or EMA from approving another marketing application for the same drug and indication for that time period, except in limited circumstances. If a competitor is able to obtain orphan drug exclusivity prior to us for a product that constitutes the same active moiety and treats the same indications as our product candidates, we may not be able to obtain approval of our drug by the applicable regulatory authority for a significant period of time unless we are able to show that our drug is clinically superior to the approved drug. The applicable period is seven years in the United States and ten years in the EU. The EU exclusivity period can be reduced to six years if a drug no longer meets the criteria for Orphan Drug Designation or if the drug is sufficiently profitable so that market exclusivity is no longer justified.

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We have obtained Orphan Drug Designation for atrasentan in the EU and may seek Orphan Drug Designation for atrasentan in the United States and other countries. However, we may not obtain Orphan Drug Designation and even if we do, Orphan Drug Designation does not guarantee future orphan drug marketing exclusivity.

Even after an orphan drug is approved, the FDA can also subsequently approve a later application for the same drug for the same condition if the FDA concludes that the later drug is clinically superior in that it is shown to be safer in a substantial portion of the target populations, more effective or makes a major contribution to patient care. In addition, a designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. Moreover, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if we are unable to manufacture sufficient quantities of the product to meet the needs of patients with the rare disease or condition. Orphan Drug Designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

We may be unsuccessful in obtaining Rare Pediatric Disease Designation for our product candidates or for future product candidates, and, even if we obtain such designation, we may be unable to maintain the benefits associated with such designation, including the potential for use or sale of a future priority review voucher.

The Rare Pediatric Disease Voucher Program is intended to encourage development of new drug and biological products for prevention and treatment of certain rare pediatric diseases. Although there are existing incentive programs to encourage the development and study of drugs for rare diseases, pediatric populations, and unmet medical needs, this program provides an additional incentive for the development of drugs for rare pediatric diseases, which may be used alone or in combination with other incentive programs. A rare pediatric disease is defined as a disease that is a serious or life-threatening disease in which the serious or life-threatening manifestations primarily affect individuals aged from birth to 18 years, including age groups often called neonates, infants, children, and adolescents; and is a rare disease or condition as defined in the FD&C Act, which includes diseases and conditions that affect fewer than 200,000 persons in the U.S. and diseases and conditions that affect a larger number of persons and for which there is no reasonable expectation that the costs of developing and making available the drug in the U.S. can be recovered from sales of the drug in the U.S.

The sponsor of a drug application for a rare pediatric disease drug product may be eligible for a voucher that can be used or sold to obtain a priority review for a subsequent drug application submitted under section 505(b)(1) of the FD&C Act or section 351 of the Public Health Service Act after the date of approval of the rare pediatric disease drug product. The rare pediatric disease priority review voucher program was most recently re-authorized by Congress in the Consolidated Appropriations Act of 2021, extending the rare pediatric disease program through September 30, 2024, with the potential for priority review vouchers to be granted through September 30, 2026. Although we have obtained designation of CHK-336 as a rare pediatric disease, we may not meet the eligibility requirements for a priority voucher at the time we seek approval of CHK-336 or we may not meet the current deadline for receiving a priority review voucher, in which case we would not be able to use priority review for a subsequent product of ours or be able to sell such voucher to a third party.

Enacted and future legislation may increase the difficulty and cost for us to commercialize and obtain marketing approval of our product candidates and may affect the prices we may set.

Existing regulatory policies may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained, and we may not achieve or sustain profitability.

For example, in March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, or collectively the Affordable Care Act, or ACA, was enacted to broaden access to health insurance, reduce or constrain the growth of healthcare spending, enhance remedies against fraud and abuse, add new transparency requirements for health care and health insurance industries, impose new taxes and fees on the health industry and impose additional health policy reforms. The law appears likely to continue the downward pressure on pharmaceutical pricing, especially under the Medicare program, and may also increase our regulatory burdens and operating costs.

There have been executive, legislative and judicial efforts to modify, repeal or otherwise invalidate all or certain aspects of the ACA. By way of example, the Tax Cuts and Jobs Act, or the TCJA, was enacted, effective January 1, 2019, and included, among other things, a provision repealing the tax-based shared responsibility payment imposed by the ACA on certain individuals who fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the “individual mandate.” In June 2021, the U.S. Supreme Court held that plaintiffs did not have standing to challenge constitutionality of the individual mandate. It is unclear whether there may be other efforts to challenge, repeal or replace the ACA. We are continuing to monitor any changes to the ACA

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that, in turn, may potentially impact our business in the future. In addition, other legislative changes have been proposed and adopted since the ACA was enacted to reduce healthcare expenditures, including aggregate reductions to Medicare payments to providers of 2 percent per fiscal year, which went into effect April 1, 2013 and will stay in effect through 2030, with the exception of a temporary suspension from May 1, 2020 through March 31, 2022 due to the COVID-19 pandemic, unless additional Congressional action is taken. The Medicare reductions phase back in starting with a 1% reduction in effect from April 1, 2022 to June 30, 2022 before increasing to the full 2% reduction. In addition, the American Taxpayer Relief Act of 2012, among other things, reduced Medicare payments to several providers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. These new laws may result in additional reductions in Medicare and other healthcare funding, which could have a material adverse effect on customers for our drugs, if approved, and accordingly, our financial operations.

Recently there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, reduce the costs of drugs under Medicare, and reform government program reimbursement methodologies for drug products. For example, in July 2021, President Biden issued an executive order pertaining to drug pricing, which expressed support for legislation allowing direct negotiation in Medicare Part D and inflationary rebates, and directed various executive branch agencies to take actions to lower drug prices and promote generic competition. Several pending legislative efforts, including President Biden’s larger Build Back Better legislative agenda and draft bill text, incorporate these drug pricing reforms in addition to inflationary rebates on Part B and Part D drugs that would be payable on commercial and governmental program utilization, policies aimed at redesigning the Medicare Part D benefit and adopting drug price transparency measures. Drug manufacturers who are unwilling to negotiate with Medicare would be subject to additional excise taxes. Additionally, the plan would impose tax penalties on drug manufacturers that increase the prices of drug products faster than the rate of inflation. If elements of the recently announced prescription drug pricing plan become law, our pricing strategy and commercial prospects may be adversely affected. It is unclear to what extent these new proposals or any future legislation or regulations by the Biden administration will have on our business, including our ability to generate revenue and achieve profitability. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

Additionally, on May 30, 2018, the Trickett Wendler, Frank Mongiello, Jordan McLinn and Matthew Bellina Right to Try Act of 2017 was signed into law. The law, among other things, provides a federal framework for certain patients to access certain investigational new drug products that have completed a phase I clinical trial and that are undergoing investigation for FDA approval. Under certain circumstances, eligible patients can seek treatment without enrolling in clinical trials and without obtaining FDA authorization under an FDA expanded access program; however, manufacturers are not obligated to provide investigational new drug products under the current federal right to try law. We may choose to seek an expanded access program for our product candidates, or to utilize comparable rules in other countries that allow the use of a drug, on a named patient basis or under a compassionate use program.

We expect that the ACA, as well as other healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and in additional downward pressure on the price that we receive for any approved product. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability, or commercialize our product candidates.

Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceutical products. We cannot be sure whether additional legislative changes will be enacted, or whether FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals of our product candidates, if any, may be. For example, the FDA may require additional trials in indications for which similar products to ours were previously approved based on smaller clinical trials or less stringent clinical outcome requirements. In addition, increased scrutiny by the U.S. Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing testing and other requirements.

The FDA’s ability to review and approve new products may be hindered by a variety of factors, including budget and funding levels, ability to hire and retain key personnel, statutory, regulatory and policy changes and global health concerns.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, statutory, regulatory and policy changes, the FDA’s ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the FDA’s ability to perform routine functions. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be

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reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, including for 35 days beginning on December 22, 2018, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA, have had to furlough critical employees and stop critical activities.

The ability of the FDA and other government agencies to properly administer their functions is highly dependent on the levels of government funding and the ability to fill key leadership appointments, among various factors. Delays in filling or replacing key positions could significantly impact the ability of the FDA and other agencies to fulfill their functions and could greatly impact healthcare and the pharmaceutical industry.

Separately, in response to the COVID-19 pandemic, on March 10, 2020, the FDA announced its intention to postpone most foreign inspections of manufacturing facilities and, subsequently, on March 18, 2020, the FDA temporarily postponed routine surveillance inspections of domestic manufacturing facilities. Subsequently, on July 10, 2020 the FDA announced its intention to resume certain on-site inspections of domestic manufacturing facilities using a risk-based prioritization system, and to conduct “mission critical” domestic and foreign inspections. The FDA may pause domestic or foreign inspections again in the future. Regulatory authorities outside the United States may adopt similar restrictions or other policy measures in response to the COVID-19 pandemic. If a prolonged government shutdown occurs, or if global health concerns continue to prevent the FDA or other regulatory authorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact the ability of the FDA or other regulatory authorities to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

Our operations and relationships with future customers, providers and third-party payors will be subject to applicable anti-kickback, fraud and abuse and other healthcare laws and regulations, which could expose us to penalties including criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future earnings.

Healthcare providers and third-party payors will play a primary role in the recommendation and prescription of any product candidates for which we obtain marketing approval. Our future arrangements with providers, third-party payors and customers will subject us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute any product candidates for which we obtain marketing approval.

Restrictions under applicable U.S. federal and state healthcare laws and regulations include the following:

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Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, imprisonment, exclusion of product candidates from government-funded healthcare programs, such as Medicare and Medicaid, disgorgement, contractual damages, reputational harm, diminished profits and future earnings, and the curtailment or restructuring of our operations. If any of the physicians or other healthcare providers or entities with whom we expect to do business is found to be not in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government-funded healthcare programs.

Risks Related to Our Intellectual Property

Our success depends in part on our ability to obtain, maintain and protect our intellectual property. It is difficult and costly to protect our proprietary rights and technology, and we may not be able to ensure their protection.

Our commercial success will depend in large part on obtaining and maintaining patent, trademark, trade secret and other intellectual property protection of our proprietary technologies and product candidates, which include atrasentan and the other product candidates we have in development, their respective components, formulations, combination therapies, methods used to manufacture them and methods of treatment, as well as successfully defending our patents and other intellectual property rights against third-party challenges. Our ability to stop unauthorized third parties from making, using, selling, offering to sell, importing or otherwise commercializing our product candidates is dependent upon the extent to which we have rights under valid and enforceable patents or trade secrets that cover these activities. If we are unable to secure and maintain patent protection for any product or technology we develop, or if the scope of the patent protection secured is not sufficiently broad, our competitors could develop and commercialize products and technology similar or identical to ours, and our ability to commercialize any product candidates we may develop may be adversely affected.

The patenting process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. In addition, we may not pursue or obtain patent protection in all relevant markets. It is also possible that we will fail to identify patentable aspects of our research and development activities before it is too late to obtain patent protection. Moreover, in some circumstances, we may not have the right to control the preparation, filing and prosecution of patent applications, or to maintain the patents, covering technology that we license from or license to third parties and may be reliant on our licensors or licensees to do so. Our pending and future patent applications may not result in issued patents. Even if patent applications we license or own currently or in the future issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors or other third parties from competing with us, or otherwise provide us with any competitive advantage. Any patents that we hold or in-license may be challenged, narrowed, circumvented or invalidated by third parties. Consequently, we do not know whether any of our platform advances and product candidates will be protectable or remain protected by valid and enforceable patents. In addition, our existing patents and any future patents we obtain may not be sufficiently broad to prevent others from using our technology or from developing competing products and technologies.

We depend on intellectual property licensed from third parties, and our licensors may not always act in our best interest. If we fail to comply with our obligations under our intellectual property licenses, if the licenses are terminated, or if disputes regarding these licenses arise, we could lose significant rights that are important to our business.

We are dependent on patents, know-how and proprietary technology licensed from others. Our licenses to such patents, know-how and proprietary technology may not provide exclusive rights in all relevant fields of use and in all territories in which we may wish to develop or commercialize our products in the future. The agreements under which we license patents, know-how and proprietary technology from others are complex, and certain provisions in such agreements may be susceptible to multiple interpretations.

For example, we are a party to a license agreement with AbbVie, pursuant to which we in-license worldwide, exclusive rights to atrasentan, including responsibility for our development and commercialization. This agreement imposes various diligence, milestone payment, royalty, insurance and other obligations on us. If we, or our sublicensees, fail to comply with these obligations, AbbVie may

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have the right to terminate our license, in which event we would not be able to develop or market atrasentan or any other technology or product candidates covered by the intellectual property licensed under this agreement. In addition, we may need to obtain additional licenses from our existing licensors and others to advance our research or allow commercialization of product candidates we may develop. It is possible that we may be unable to obtain any additional licenses at a reasonable cost or on reasonable terms, if at all. In either event, we may be required to expend significant time and resources to redesign our technology, product candidates, or the methods for manufacturing them or to develop or license replacement technology, all of which may not be feasible on a technical or commercial basis. If we are unable to do so, we may be unable to develop or commercialize the affected technology or product candidates.

If our licensors fail to adequately protect our licensed intellectual property, our ability to commercialize product candidates could suffer. We do not have complete control over the maintenance, prosecution and litigation of our in-licensed patents and patent applications and may have limited control over future intellectual property that may be in-licensed. For example, we cannot be certain that activities such as the maintenance and prosecution by our licensors have been or will be conducted in compliance with applicable laws and regulations or will result in valid and enforceable patents and other intellectual property rights. It is possible that our licensors’ infringement proceedings or defense activities may be less vigorous than had we conducted them ourselves or may not be conducted in accordance with our best interests.

In addition, the resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant patents, know-how and proprietary technology, or increase what we believe to be our financial or other obligations under the relevant agreement. Disputes that may arise between us and our licensors regarding intellectual property subject to a license agreement could include disputes regarding:

If disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on acceptable terms, we may be unable to successfully develop and commercialize the affected technology or product candidates.

Our owned and in-licensed patents and patent applications may not provide sufficient protection of our atrasentan product candidate and our other product candidates or result in any competitive advantage.

We have in-licensed issued U.S. patents and foreign patent applications that cover formulations and methods of use related directly to atrasentan from AbbVie. We have filed patent applications intended to specifically cover additional methods of treatment and combinations of atrasentan with other therapies in kidney disease. We cannot be certain that any of these patent applications will issue as patents, and if they do, that such patents will cover or adequately protect atrasentan or that such patents will not be challenged, narrowed, circumvented, invalidated or held unenforceable.

In addition to claims directed toward the technology underlying atrasentan, our owned and in-licensed patents and patent applications contain claims directed to compositions of matter on the active pharmaceutical ingredients, or APIs, in BION-1301, CHK-336 and our other product candidates, as well as methods-of-use directed to the use of such APIs for a specified treatment. Composition-of-matter patents on the API in prescription drug products provide protection without regard to any particular method of use of the API used. Method-of-use patents do not prevent a competitor or other third party from developing or marketing an identical product for an indication that is outside the scope of the patented method. Patents covering methods-of-use are not available in certain foreign countries, in which case we may not be able to prevent competitors or third parties from marketing our product candidates in those countries. Moreover, with respect to method-of-use patents, even if competitors or other third parties do not actively promote their product for our targeted indications or uses for which we may obtain patents, providers may recommend that patients use these products off-label, or patients may do so themselves. Although off-label use may infringe or contribute to the infringement of method-of-use patents, the practice is common, and this type of infringement is difficult to prevent or prosecute.

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The strength of patents in the biotechnology and pharmaceutical field involves complex legal and scientific questions and can be uncertain. The patent applications that we own or in-license may fail to result in issued patents with claims that cover our product candidates or uses thereof in the United States or in other foreign countries. For example, while our patent applications are pending, we may be subject to a third party preissuance submission of prior art to the United States Patent and Trademark Office, or USPTO, or become involved in interference or derivation proceedings, or equivalent proceedings in foreign jurisdictions. Even if patents do successfully issue, third parties may challenge their inventorship, validity, enforceability or scope, including through opposition, revocation, reexamination, post-grant and inter partes review proceedings. An adverse determination in any such submission, proceeding or litigation may result in loss of patent rights, loss of exclusivity, or in patent claims being narrowed, invalidated or held unenforceable, which could limit our ability to stop others from using or commercializing similar or identical technology and products, or limit the duration of the patent protection of our technology and product candidates. Furthermore, even if they are unchallenged, our patents and patent applications may not adequately protect our intellectual property or prevent others from designing around our claims. Moreover, some of our owned and in-licensed patents and patent applications may be co-owned with third parties. If we are unable to obtain an exclusive license to any such third-party co-owners’ interest in such patents or patent applications, such co-owners may be able to license their rights to other third parties, including our competitors, and our competitors could market competing products and technology. In addition, we may need the cooperation of any such co-owners of our patents in order to enforce such patents against third parties, and such cooperation may not be provided to us. If the breadth or strength of protection provided by the patent applications we hold with respect to our product candidates is threatened, it could dissuade companies from collaborating with us to develop, and threaten our ability to commercialize, our product candidates. Further, if we encounter delays in development, testing, and regulatory review of new product candidates, the period of time during which we could market our product candidates under patent protection would be reduced or eliminated.

Since patent applications in the United States and other countries are confidential for a period of time after filing, at any moment in time, we cannot be certain that we were in the past or will be in the future the first to file any patent application related to our product candidates. In addition, some patent applications in the United States may be maintained in secrecy until the patents are issued. As a result, there may be prior art of which we are not aware that may affect the validity or enforceability of a patent claim, and we may be subject to priority disputes. We may be required to disclaim part or all of the term of certain patents or all of the term of certain patent applications. There may be prior art of which we are not aware that may affect the validity or enforceability of a patent claim. There also may be prior art of which we are aware, but which we do not believe affects the validity or enforceability of a claim, which may, nonetheless, ultimately be found to affect the validity or enforceability of a claim. No assurance can be given that, if challenged, our patents would be declared by a court, patent office or other governmental authority to be valid or enforceable or that even if found valid and enforceable, a competitor’s technology or product would be found by a court to infringe our patents. We may analyze patents or patent applications of our competitors that we believe are relevant in our activities, and consider that we are free to operate in relation to our product candidates, but our competitors may achieve issued claims, including in patents we consider to be unrelated, that block our efforts or potentially result in our product candidates or our activities infringing such claims. It is possible that our competitors may have filed, and may in the future file, patent applications covering our products or technology similar to our own products or technology. Those patent applications may have priority over our owned and in-licensed patent applications or patents, which could require us to obtain rights to issued patents covering such technologies. The possibility also exists that others will develop products that have the same effect as our product candidates on an independent basis that do not infringe our patents or other intellectual property rights, or will design around the claims of patents that we have had issued that cover our product candidates or their use.

Likewise, our currently owned and in-licensed patents and patent applications, if issued as patents, directed to our proprietary technologies and our product candidates are expected to expire from 2028 through 2041, without taking into account any possible patent term adjustments or extensions. Our earliest in-licensed patents may expire before, or soon after, our first product achieves marketing approval in the United States or foreign jurisdictions. Additionally, we cannot be assured that the USPTO or relevant foreign patent offices will grant any of the pending patent applications we own or in-license currently or in the future. Upon the expiration of our current patents, we may lose the right to exclude others from practicing these inventions. The expiration of these patents could also have a similar material adverse effect on our business, financial condition, results of operations and prospects.

The degree of future protection for our proprietary rights is uncertain because legal means afford only limited protection and may not adequately protect our rights or permit us to gain or keep our competitive advantage. For example:

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Any of the foregoing could have a material adverse effect on our business, financial conditions, results of operations and prospects.

Our strategy of obtaining rights to key technologies through in-licenses may not be successful.

The future growth of our business will depend in part on our ability to in-license or otherwise acquire the rights to additional product candidates and technologies. Although we have succeeded in licensing technology from AbbVie and others in the past, we cannot assure you that we will be able to in-license or acquire the rights to any product candidates or technologies from third parties on acceptable terms or at all.

For example, our agreements with certain of our third-party research partners provide that improvements developed in the course of our relationship may be owned solely by either us or our third-party research partner, or jointly between us and the third party. If we determine that exclusive rights to such improvements owned solely by a research partner or other third party with whom we collaborate are necessary to commercialize our product candidates or maintain our competitive advantage, we may need to obtain an exclusive license from such third party in order to use the improvements and continue developing, manufacturing or marketing our product candidates. We may not be able to obtain such a license on an exclusive basis, on commercially reasonable terms, or at all, which could prevent us from commercializing our product candidates or allow our competitors or others the opportunity to access technology that is important in our business. We also may need the cooperation of any co-owners of our intellectual property in order to enforce such intellectual property against third parties, and such cooperation may not be provided to us.

In addition, in-licensing and acquisition of these technologies is a highly competitive area, and a number of more established companies are also pursuing strategies to license or acquire product candidates or technologies that we may consider attractive. These established companies may have a competitive advantage over the Company due to their size, cash resources and greater clinical development and commercialization capabilities. In addition, companies that perceive the Company to be a competitor may be unwilling to license rights to the Company. Furthermore, we may be unable to identify suitable product candidates or technologies

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within our area of focus. If we are unable to successfully obtain rights to suitable product candidates or technologies, our business and prospects could be materially and adversely affected.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to patent protection, we rely upon know-how and trade secret protection, as well as non-disclosure agreements and invention assignment agreements with our employees, consultants and third-parties, to protect our confidential and proprietary information, especially where we do not believe patent protection is appropriate or obtainable.

It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with the Company. These agreements provide that all confidential information concerning our research and development, business, or financial affairs developed or made known to the individual or entity during the course of the party’s relationship with Chinook Therapeutics are to be kept confidential and not disclosed to third parties, except in certain specified circumstances. In the case of employees, the agreements provide that all inventions conceived by the individual, and that are related in our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information (or as otherwise permitted by applicable law), are our exclusive property. In the case of consultants and other third parties, the agreements provide that all inventions conceived in connection with the services provided are our exclusive property. However, we cannot guarantee that we have entered into such agreements with each party that may have or have had access to our trade secrets or proprietary technology and processes. We have also adopted policies and conduct training that provides guidance on our expectations, and our advice for best practices, in protecting our secrets. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches.

In addition to contractual measures, we try to protect the confidential nature of our proprietary information through other appropriate precautions, such as physical and technological security measures. However, trade secrets and know-how can be difficult to protect. These measures may not, for example, in the case of misappropriation of a trade secret by an employee or third party with authorized access, provide adequate protection for our proprietary information. Our security measures may not prevent an employee or consultant from misappropriating our trade secrets and providing them to a competitor, and any recourse we might take against this type of misconduct may not provide an adequate remedy to protect our interests fully. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret can be difficult, expensive, and time-consuming, and the outcome is unpredictable. In addition, trade secrets may be independently developed by others in a manner that could prevent us from receiving legal recourse. If any of our confidential or proprietary information, such as the Company’s trade secrets, were to be disclosed or misappropriated, such as through a data breach, or if any of that information was independently developed by a competitor, our competitive position could be harmed. Additionally, certain trade secrets and proprietary information may be required to be disclosed in submissions to regulatory authorities. If such authorities do not maintain the confidential basis of such information or disclose it as part of the basis of regulatory approval, our competitive position could be adversely affected.

In addition, courts outside the United States are sometimes less willing to protect trade secrets. If we choose to go to court to stop a third party from using any of our trade secrets, we may incur substantial costs. Even if we are successful, these types of lawsuits may consume our time and other resources. Although we take steps to protect our proprietary information and trade secrets, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access in our trade secrets or disclose our technology, through legal or illegal means. As a result, we may not be able to meaningfully protect the Company’s trade secrets. Any of the foregoing could have a material adverse effect on our business, financial condition, results of operations and prospects.

Third-party claims of intellectual property infringement may prevent, delay or otherwise interfere with our product discovery and development efforts.

Our commercial success depends in part on our ability to develop, manufacture, market and sell our product candidates and use our proprietary technologies without infringing, misappropriating or otherwise violating the intellectual property or other proprietary rights of third parties. There is a substantial amount of litigation involving patents and other intellectual property rights in the biotechnology and pharmaceutical industries, as well as administrative proceedings for challenging patents, including interference, derivation, inter partes review, post grant review, and reexamination proceedings before the USPTO or oppositions and other comparable proceedings in foreign jurisdictions. We may be exposed to, or threatened with, future litigation by third parties having patent or other intellectual property rights alleging that our product candidates and/or proprietary technologies infringe, misappropriate or otherwise violate their intellectual property rights. Numerous U.S. and foreign issued patents and pending patent applications that are owned by third parties exist in the fields in which we are developing our product candidates. As the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that our product candidates may give rise to claims of infringement of the patent rights of others. Moreover, it is not always clear to industry participants, including us, which patents cover

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various types of drugs, products or their methods of use or manufacture. Thus, because of the large number of patents issued and patent applications filed in our field, third parties may allege they have patent rights encompassing our product candidates, technologies or methods.

If a third party claims that we infringe, misappropriate or otherwise violate our intellectual property rights, we may face a number of issues, including, but not limited to:

Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. In addition, any uncertainties resulting from the initiation and continuation of any litigation could have a material adverse effect on our ability to raise the funds necessary to continue our operations or could otherwise have a material adverse effect on our business, financial condition, results of operations and prospects.

Third parties may assert that we are employing their proprietary technology without authorization, including by enforcing its patents against us by filing a patent infringement lawsuit against the Company. In this regard, patents issued in the United States by law enjoy a presumption of validity that can be rebutted only with evidence that is “clear and convincing,” a heightened standard of proof.

There may be third-party patents of which we are currently unaware with claims to materials, formulations, methods of manufacture or methods for treatment related to the use or manufacture of our product candidates. Because patent applications can take many years to issue, there may be currently pending patent applications that may later result in issued patents that our product candidates may infringe. In addition, third parties may obtain patents in the future and claim that use of our technologies infringes upon these patents.

If any third-party patents were held by a court of competent jurisdiction to cover the manufacturing process of our product candidates, or materials used in or formed during the manufacturing process, or any final product itself, the holders of those patents may be able to block our ability to commercialize our product candidate unless we obtain a license under the applicable patents, or until those patents were to expire or those patents are finally determined to be invalid or unenforceable. Similarly, if any third-party patent were held by a court of competent jurisdiction to cover aspects of our formulations, processes for manufacture or methods of use, including combination therapy or patient selection methods, the holders of that patent may be able to block our ability to develop and commercialize the product candidate unless we obtain a license or until such patent expires or is finally determined to be invalid or unenforceable. In either case, a license may not be available on commercially reasonable terms, or at all, particularly if such patent is owned or controlled by one of our primary competitors. If we are unable to obtain a necessary license to a third-party patent on commercially reasonable terms, or at all, our ability to commercialize our product candidates may be impaired or delayed, which could significantly harm our business. Even if we obtain a license, it may be non-exclusive, thereby giving our competitors access to the same technologies licensed to the Company. In addition, if the breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

Parties making claims against us may seek and obtain injunctive or other equitable relief, which could effectively block our ability to further develop and commercialize our product candidates. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee time and resources from our business. In the event of a

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successful claim of infringement against the Company, we may have to pay substantial damages, including treble damages and attorneys’ fees for willful infringement, obtain one or more licenses from third parties, pay royalties or redesign our infringing products, which may be impossible or require substantial time and monetary expenditure. We cannot predict whether any license of this nature would be available at all or whether it would be available on commercially reasonable terms. Furthermore, even in the absence of litigation, we may need to obtain licenses from third parties to advance our research or allow commercialization of our product candidates and we may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all. In that event, we would be unable to further develop and commercialize our product candidates, which could significantly harm our business.

We may be involved in lawsuits to protect or enforce our patents or the patents of our licensors, which could be expensive, time-consuming and unsuccessful and could result in a finding that such patents are unenforceable or invalid.

Competitors may infringe our patents or the patents of our licensors. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time-consuming. In addition, in an infringement proceeding, a court may decide that one or more of our patents is not valid or is unenforceable, or may refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question.

In patent litigation in the United States, defendant counterclaims alleging invalidity and/or unenforceability are commonplace, and there are numerous grounds upon which a third party can assert invalidity or unenforceability of a patent. Third parties may also raise similar claims before administrative bodies in the United States or abroad, even outside the context of litigation. These types of mechanisms include re-examination, post-grant review, inter partes review, interference proceedings, derivation proceedings, and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings). These types of proceedings could result in revocation or amendment to our patents such that they no longer cover our product candidates. The outcome for any particular patent following legal assertions of invalidity and unenforceability is unpredictable. With respect to the validity question, for example, we cannot be certain that there is no invalidating prior art, of which we, our patent counsel and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal assertion of invalidity and/or unenforceability, or if we are otherwise unable to adequately protect our rights, we would lose at least part, and perhaps all, of the patent protection on our product candidates. Defense of these types of claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee resources from our business.

Conversely, we may choose to challenge the patentability of claims in a third party’s U.S. patent by requesting that the USPTO review the patent claims in re-examination, post-grant review, inter partes review, interference proceedings, derivation proceedings, and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings), or we may choose to challenge a third party’s patent in patent opposition proceedings in the Canadian Intellectual Property Office, or CIPO, the European Patent Office, or EPO, or another foreign patent office. Even if successful, the costs of these opposition proceedings could be substantial, and may consume our time or other resources. If we fail to obtain a favorable result at the USPTO, CIPO, EPO or other patent office then we may be exposed to litigation by a third party alleging that the patent may be infringed by our product candidates or proprietary technologies.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, that perception could have a substantial adverse effect on the price of our common stock. Any of the foregoing could have a material adverse effect on our business financial condition, results of operations and prospects.

We have limited foreign intellectual property rights and may not be able to protect our intellectual property rights throughout the world.

We currently have limited intellectual property rights outside the United States. Filing, prosecuting and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the United States can be less extensive than those in the United States. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States. For example, patents covering methods-of-use are not available in certain foreign countries. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we do not have or have not obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories where we have patent protection but where enforcement is not as strong as that in the United States. These products may compete with our product candidates in jurisdictions where we do not have any issued patents and our patent claims or other intellectual property rights may not be effective or sufficient to prevent them from competing.

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Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets and other intellectual property protection, particularly those relating to biopharmaceutical products, which could make it difficult for us to stop the infringement of our patents or marketing of competing products against third parties in violation of our proprietary rights generally. The initiation of proceedings by third parties to challenge the scope or validity of our patent rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Third parties may assert that our employees or consultants have wrongfully used or disclosed confidential information or misappropriated trade secrets.

As is common in the biotechnology and pharmaceutical industries, we employ individuals who were previously employed at universities or other biopharmaceutical or pharmaceutical companies, including our competitors or potential competitors. Although we try to ensure that our employees and consultants do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that our employees, consultants or independent contractors have inadvertently or otherwise used or disclosed intellectual property, including trade secrets or other proprietary information, of a former employer or other third parties. We may then have to pursue litigation to defend against these claims. If we fail in defending any claims of this nature, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against these types of claims, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments, and, if securities analysts or investors perceive these results to be negative, that perception could have a substantial adverse effect on the price of our common stock. This type of litigation or proceeding could substantially increase our operating losses and reduce our resources available for development activities, and we may not have sufficient financial or other resources to adequately conduct this type of litigation or proceeding. For example, some of our competitors may be able to sustain the costs of this type of litigation or proceeding more effectively than we can because of their substantially greater financial resources. In any case, uncertainties resulting from the initiation and continuation of intellectual property litigation or other intellectual property related proceedings could adversely affect our ability to compete in the marketplace.

We may not be successful in obtaining or maintaining necessary rights to product components and processes for our development pipeline through acquisitions and in-licenses.

The growth of our business may depend in part on our ability to acquire, in-license or use third-party proprietary rights. For example, our product candidates may require specific formulations to work effectively and efficiently, we may develop product candidates containing pre-existing pharmaceutical compounds, or we may be required by the FDA or comparable foreign regulatory authorities to provide a companion diagnostic test or tests with our product candidates, any of which could require us to obtain rights to use intellectual property held by third parties. In addition, with respect to any patents we may co-own with third parties, we may require licenses to such co-owners' interest in such patents. We may be unable to acquire or in-license any compositions, methods of use, processes or other third-party intellectual property rights from third parties we identify as necessary or important in our business operations. In addition, we may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all. Were that to happen, we may need to cease use of the compositions or methods covered by those third-party intellectual property rights, and may need to seek to develop alternative approaches that do not infringe on those intellectual property rights, which may entail additional costs and development delays, even if we were able to develop such alternatives, which may not be feasible. Even if we are able to obtain a license, it may be non-exclusive, which means of our competitors may also receive access to the same technologies licensed to us. In that event, we may be required to expend significant time and resources to develop or license replacement technology.

Additionally, we sometimes collaborate with academic institutions to accelerate our preclinical research or development under written agreements with these institutions. In certain cases, these institutions provide us with an option to negotiate a license to any of the institution’s rights in technology resulting from the collaboration. Even if we hold such an option, we may be unable to negotiate a license from the institution within the specified timeframe or under terms that are acceptable to us. If we are unable to do so, the institution may offer the intellectual property rights to others, potentially blocking our ability to pursue our program.

The licensing and acquisition of third-party intellectual property rights is a competitive area, and companies that may be more established or have greater resources than we do may also be pursuing strategies to license or acquire third-party intellectual property rights that we may consider necessary or attractive in order to commercialize our product candidates. More established companies

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may have a competitive advantage over us due to their size, cash resources and greater clinical development and commercialization capabilities. In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights to us. There can be no assurance that we will be able to successfully complete these types of negotiations and ultimately acquire the rights to the intellectual property surrounding the additional product candidates that we may seek to develop or market. If we are unable to successfully obtain rights to required third-party intellectual property or to maintain the existing intellectual property rights we have, we may have to abandon development of certain programs and our business financial condition, results of operations and prospects could suffer.

Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance fees on any issued patent are due to be paid to the USPTO and foreign patent agencies in several stages over the lifetime of the patent. The USPTO and various foreign patent agencies also require compliance with a number of procedural, documentary, fee payment and other provisions during the patent application process and following the issuance of a patent. While an inadvertent lapse can in many cases be cured by payment of a late fee or by other means in accordance with the applicable laws and rules, there are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. Noncompliance events that could result in abandonment or lapse of a patent or patent application include, but are not limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to properly legalize and submit formal documents. Were a noncompliance event to occur, our competitors might be able to enter the market, which would have a material adverse effect on our business financial condition, results of operations and prospects.

Changes in patent law in the United States and in non-U.S. jurisdictions could diminish the value of patents in general, thereby impairing our ability to protect our product candidates.

As is the case with other biopharmaceutical companies, our success is heavily dependent on intellectual property, particularly patents. Obtaining and enforcing patents in the biopharmaceutical industry involve both technological and legal complexity, and is therefore costly, time-consuming and inherently uncertain.

Past or future patent reform legislation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents. For example, in March 2013, under the Leahy-Smith America Invents Act, or America Invents Act, the United States moved from a “first to invent” to a “first-to-file” patent system. Under a “first-to-file” system, assuming the other requirements for patentability are met, the first inventor to file a patent application generally will be entitled to a patent on the invention regardless of whether another inventor had made the invention earlier. The America Invents Act includes a number of other significant changes to U.S. patent law, including provisions that affect the way patent applications are prosecuted, redefine prior art and establish a new post-grant review system. The effects of these changes continue to evolve as the USPTO continues to promulgate new regulations and procedures in connection with the America Invents Act and many of the substantive changes to patent law, including the “first-to-file” provisions, only became effective in March 2013. In addition, the courts have yet to address many of these provisions and the applicability of the act and new regulations on the specific patents discussed in this filing have not been determined and would need to be reviewed. Moreover, the America Invents Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents.

Additionally, recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in certain situations. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal courts and the USPTO, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future. For example, in the case, Assoc. for Molecular Pathology v. Myriad Genetics, Inc., the U.S. Supreme Court held that certain claims to DNA molecules are not patent-eligible.

Similarly, other cases by the U.S. Supreme Court have held that certain methods of treatment or diagnosis are not patent-eligible. U.S. law regarding patent-eligibility continues to evolve. While we do not believe that any of our owned or in-licensed patents will be found invalid based on these changes to U.S. patent law, we cannot predict how future decisions by the courts, the U.S. Congress or the USPTO may impact the value of our patents. Any similar adverse changes in the patent laws of other jurisdictions could also have a material adverse effect on our business, financial condition, results of operations and prospects.

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Patent terms may be inadequate to protect our competitive position on our product candidates for an adequate amount of time.

Patents have a limited lifespan. In the United States, if all maintenance fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest U.S. non-provisional filing date. Various extensions may be available, but the life of a patent, and the protection it affords, is limited. Even if patents covering our product candidates are obtained, once the patent life has expired, we may be open to competition from competitive products, including generics. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting our product candidates might expire before or shortly after we or our partners commercialize those candidates. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to our products.

If we do not obtain patent term extension for any product candidates we may develop, our business may be materially harmed.

Depending upon the timing, duration and specifics of any FDA marketing approval of any product candidates we may develop, one or more of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent extension term of up to five years as compensation for patent term lost during clinical trials and the FDA regulatory review process. A patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent per product may be extended and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended. U.S. and ex-U.S. law concerning patent term extensions and foreign equivalents continue to evolve. Even if we were to seek a patent term extension, it may not be granted because of, for example, the failure to exercise due diligence during the testing phase or regulatory review process, the failure to apply within applicable deadlines, the failure to apply prior to expiration of relevant patents, or any other failure to satisfy applicable requirements. Moreover, the applicable time period of extension or the scope of patent protection afforded could be less than we request. If we are unable to obtain patent term extension or term of any such extension is less than it requests, our competitors may obtain approval of competing products following our patent expiration sooner than expected, and our business, financial condition, results of operations and prospects could be materially harmed.

Some intellectual property that we have in-licensed may have been discovered through government funded programs and thus may be subject to federal regulations such as “march-in” rights, certain reporting requirements and a preference for U.S.-based companies. Compliance with such regulations may limit our exclusive rights, and limit our ability to contract with non-U.S. manufacturers.

Inventions contained within some of our in-licensed patents and patent applications may have been made using U.S. government funding or other non-governmental funding. As a result, the U.S. government may have certain rights to intellectual property embodied in our current or future product candidates pursuant to the Bayh-Dole Act of 1980, or Bayh-Dole Act, and implementing regulations. We rely on our licensors to ensure compliance with applicable obligations arising from such funding, such as timely reporting, an obligation associated with in-licensed patents and patent applications. The failure of our licensors to meet their obligations may lead to a loss of rights or the unenforceability of relevant patents. For example, the government could have certain rights in such in-licensed patents, including a non-exclusive license authorizing the government to use the invention or to have others use the invention on its behalf for non-commercial purposes. In addition, our rights in such in-licensed government-funded inventions may be subject to certain requirements to manufacture products embodying such inventions in the United States. Any of the foregoing could harm our business, financial condition, results of operations and prospects significantly.

Risks Related to Employee Matters, Managing Growth and Other Risks Related to Our Business

We expect to expand our development and regulatory capabilities, and as a result, we may encounter difficulties in managing our growth, which could disrupt our operations.

We expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of product candidate development, growing our capability to conduct clinical trials, and, if approved, through commercialization of our product candidates. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel, or contract with third parties to provide these capabilities for us. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

Future acquisitions or strategic alliances could disrupt our business and harm our financial condition and results of operations.

We may acquire additional businesses or drugs, form strategic alliances or create joint ventures with third parties that we believe will complement or augment our existing business. If we acquire businesses with promising markets or technologies, we may not be

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able to realize the benefit of acquiring such businesses if we are unable to successfully integrate them with our existing operations and company culture. We may encounter numerous difficulties in developing, manufacturing and marketing any new drugs resulting from a strategic alliance or acquisition that delay or prevent us from realizing their expected benefits or enhancing our business. We cannot assure you that, following any such acquisition, we will achieve the expected synergies to justify the transaction. The risks we face in connection with acquisitions, include:

Our failure to address these risks or other problems encountered in connection with our past or future acquisitions or strategic alliances could cause us to fail to realize the anticipated benefits of these transactions, cause us to incur unanticipated liabilities and harm the business generally. There is also a risk that future acquisitions will result in the incurrence of debt, contingent liabilities, amortization expenses or incremental operating expenses, any of which could harm our financial condition or results of operations.

Our employees, principal investigators, CROs, CMOs and consultants may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements and insider trading.

We are exposed to the risk of fraud or other misconduct by our employees, principal investigators, consultants and commercial partners. Misconduct by these parties could include intentional failures to comply with the regulations of FDA and non-U.S. regulators, provide accurate information to the FDA and non-U.S. regulators, comply with healthcare fraud and abuse laws and regulations in the United States and abroad, report financial information or data accurately or disclose unauthorized activities to us. In particular, sales, marketing and business arrangements in the healthcare industry are subject to extensive laws and regulations intended to prevent fraud, misconduct, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive programs and other business arrangements. Such misconduct could also involve the improper use of information obtained in the course of clinical studies, which could result in regulatory sanctions and cause serious harm to our reputation. It is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any such actions are instituted against us, and we are not successful in defending or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant fines or other sanctions.

Our business entails a significant risk of product liability and our ability to obtain sufficient insurance coverage could have a material and adverse effect on our business, financial condition, results of operations and prospects.

We will face an inherent risk of product liability exposure related to the testing of atrasentan and our other product candidates in clinical trials and will face an even greater risk if we commercialize any of our product candidates. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in a product, negligence, strict liability or breach of warranty. Claims could also be asserted under U.S. state consumer protection acts. If we cannot successfully defend itself against claims of our product candidates caused injuries, then we could incur substantial liabilities. Regardless of merit or eventual outcome, liability claims may result in:

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While we currently have insurance that we believe is appropriate for our stage of development, we may need to obtain higher levels prior to clinical development or marketing atrasentan or any of our future product candidates. Any insurance we have or may obtain may not provide sufficient coverage against potential liabilities. Furthermore, clinical trial and product liability insurance is becoming increasingly expensive. As a result, we may be unable to obtain sufficient insurance at a reasonable cost to protect us against losses caused by product liability claims that could have a material and adverse effect on our business, financial condition, results of operations and prospects.

Our ability to utilize our net operating loss carryforwards may be subject to limitations.

To the extent our taxable income exceeds any current year operating losses, we plan to use our net operating loss carryforwards to offset income that would otherwise be taxable. Under Section 382 of the Code, changes in a company’s ownership may limit the amount of net operating loss carryforwards and tax credit carryforwards that could be utilized annually to offset its future taxable income, if any. This limitation generally applies in the event of a cumulative change in ownership of more than 50 percent within a three-year period. Aduro experienced and Private Chinook likely experienced an ownership change under Section 382 as a result of the Merger. Any such limitation may significantly reduce our ability to utilize net operating loss carryforwards and tax credit carryforwards before they expire. Consequently, even if we achieve profitability, we may not be able to utilize a material portion of Private Chinook’s or Aduro’s net operating loss carryforwards and other tax attributes, which could have a material adverse effect on our cash flow and results of operations. There is also a risk that due to regulatory changes, such as suspensions on the use of net operating losses, or NOLs, or other unforeseen reasons, our existing NOLs could expire or otherwise be unavailable to offset future income tax liabilities.

Under the TCJA, as modified by the CARES Act, NOLs and other carryforwards generated in tax years that began after December 31, 2017 may offset no more than 80 percent of current taxable income annually for taxable years beginning after December 31, 2020. Accordingly, we, Private Chinook or Aduro, as applicable, generated or will generate NOLs after the tax year ended December 31, 2017, and we might have to pay more federal income taxes in a subsequent year as a result of the 80 percent taxable income limitation than we would have had to pay under the law in effect before the Tax Act as modified by the CARES Act.

Risks Related to the CVRs

Our outstanding CVRs may expire valueless.

The right of the holders of our contingent value rights, or CVRs, issued prior to the closing of the Merger will be contingent solely upon the occurrence of the milestones described in the CVR agreement and the consideration received being greater than the amounts that could be deducted by us under the CVR Agreement. In April 2021, prior to the disposition period set forth in the CVR agreement, we entered into an agreement with Sairopa, a private company created by Van Herk Royalty B.V. and D.S. Chahal to acquire certain of our non-renal assets in exchange for stock in Sairopa. We will hold our equity interests in Sairopa until there is a liquidity event, upon which 50% of any proceeds, net of deductions permitted under the CVR Agreement, including taxes and certain other expenses, will be distributed to CVR holders, provided such liquidity event occurs during the 10-year CVR period. In the event that no CVR milestones occur within the 10-year CVR period specified in the CVR Agreement or the consideration received is not greater than the amounts that could be deducted by us, no payments will be made under the CVR Agreement, and the CVRs will expire valueless.

We do not have any obligation to develop the non-renal assets, or to expend any effort or resources to divest or otherwise monetize the non-renal assets.  Furthermore, the CVRs are unsecured obligations of us and all payments under the CVRs, all other obligations under the CVR Agreement and the CVRs and any rights or claims relating thereto may be subordinated in right of payment to the prior payment in full of all current or future senior obligations of us.

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The tax treatment of the CVRs is unclear.

The U.S. federal income tax treatment of the CVRs is unclear. There is no legal authority directly addressing the U.S. federal income tax treatment of the receipt of, and payments under, the CVRs, and there can be no assurance that the IRS would not assert, or that a court would not sustain, a position that could result in adverse U.S. federal income tax consequences to holders of the CVRs.

For example, Aduro did not report the issuance of the CVRs as a current distribution of property with respect to its common stock, but it is possible that the IRS could assert that CVR recipients are treated as having received a distribution of property equal to the fair market value of the CVRs on the date the CVRs are distributed, which could be taxable to such recipients without the corresponding receipt of cash. In addition, it is possible that the IRS or a court could determine that the issuance of the CVRs (and/or any payments thereon) and the reverse stock split constitute a single “recapitalization” for U.S. federal income tax purposes with the CVRs constituting taxable “boot” received in such recapitalization exchange. In such case, the tax consequences of the CVRs and the reverse stock split would differ from those described in the Merger proxy statement, including with respect to the timing and character of income.

Risks Related to our Common Stock

The market price of our common stock is expected to be volatile, and the market price of the common stock may drop in the future.

The market price of our common stock is subject to significant fluctuations. Some of the factors that may cause the market price of our common stock to fluctuate include:

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Moreover, the stock markets in general have experienced substantial volatility that has often been unrelated to the operating performance of individual companies. These broad market fluctuations may also adversely affect the trading price of our common stock. In addition, a recession, depression or other sustained adverse market event resulting from the spread of COVID-19 or otherwise could materially and adversely affect our business and the value of our common stock. Furthermore, the trading price of our common stock may be adversely affected by third-parties trying to drive down the market price. Short sellers and others, some of whom post anonymously on social media, may be positioned to profit if our stock declines and their activities can negatively affect our stock price. In the past, following periods of volatility in the market price of a company’s securities, stockholders have often instituted class action securities litigation against such companies. Furthermore, market volatility may lead to increased shareholder activism if we have a market valuation that activists believe is not reflective of our intrinsic value. Activist campaigns that contest or conflict with our strategic direction or seek changes in the composition of our board of directors could have an adverse effect on our operating results and financial condition.

We will incur additional costs and increased demands upon management as a result of complying with the laws and regulations affecting public companies.

We will incur significant legal, accounting and other expenses as a public company that we did not incur as a private company, including costs associated with public company reporting obligations under the Securities Exchange Act of 1934, as amended, or the Exchange Act. Our management team consists, among others, of the executive officers of Private Chinook prior to the Merger, some of whom have not previously managed and operated a public company. These executive officers and other personnel will need to devote substantial time to gaining expertise related to public company reporting requirements and compliance with applicable laws and regulations to ensure that we comply with all of these requirements. Any changes we make to comply with these obligations may not be sufficient to allow it to satisfy our obligations as a public company on a timely basis, or at all. These reporting requirements, rules and regulations, coupled with the increase in potential litigation exposure associated with being a public company, could also make it more difficult for us to attract and retain qualified persons to serve on the board of directors or on board committees or to serve as executive officers, or to obtain certain types of insurance, including directors’ and officers’ insurance, on acceptable terms.

Once we are no longer a smaller reporting company or otherwise no longer qualify for applicable exemptions, we will be subject to additional laws and regulations affecting public companies that will increase our costs and the demands on management and could harm our operating results.

We are subject to the reporting requirements of the Exchange Act, which requires, among other things, that we file with the SEC, annual, quarterly and current reports with respect to our business and financial condition as well as other disclosure and corporate governance requirements. We currently qualify as a “smaller reporting company,” as such term is defined in Rule 12b-2 under the Exchange Act, which allows us to take advantage of many exemptions from disclosure requirements applicable to smaller reporting companies and non-accelerated filers, including not being required to have our independent auditors attest to its internal control over financial reporting under Section 404 of the Sarbanes-Oxley Act of 2002 and reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements. Once we are no longer, a smaller reporting company or otherwise qualify for these exemptions, we will be required to comply with these additional legal and regulatory requirements applicable to public companies and may incur significant legal, accounting and other expenses to do so. If we are not able to comply with the requirements in a timely manner or at all, our financial condition or the market price of our common stock may be harmed. For example, if we or our independent auditor identifies deficiencies in our internal control over financial reporting that are deemed to be material weaknesses, we could face additional costs to remedy those deficiencies, the market price of our stock could decline or we could be subject to sanctions or investigations by the SEC or other regulatory authorities, which would require additional financial and management resources.

Provisions in our charter documents and under Delaware law could make an acquisition more difficult and may discourage any takeover attempts the company stockholders may consider favorable, and may lead to entrenchment of management.

Provisions of our amended and restated certificate of incorporation and amended and restated bylaws could delay or prevent changes in control or changes in management without the consent of the board of directors. These provisions include the following:

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In addition, these provisions would apply even if we were to receive an offer that some stockholders may consider beneficial.

We are also subject to the anti-takeover provisions contained in Section 203 of the DGCL, or Section 203. Under Section 203, a corporation may not, in general, engage in a business combination with any holder of 15 percent or more of its capital stock unless the holder has held the stock for three years or, among other exceptions, the board of directors has approved the transaction.

Our certificate of incorporation and bylaws provides that the Court of Chancery of the State of Delaware is the exclusive forum for substantially all disputes between us and our stockholders, and that federal district court is the exclusive forum for any actions arising under the Exchange Act, which could limit your ability to obtain a favorable judicial forum for disputes with us or our directors, officers or other employees.

Our certificate of incorporation and bylaws provides that the Court of Chancery of the State of Delaware is the sole and exclusive forum for any derivative action or proceeding brought on the Company’s behalf, any action asserting a breach of fiduciary duty, any action asserting a claim against it arising pursuant to any provisions of the DGCL, its certificate of incorporation or its bylaws, or any action asserting a claim against it that is governed by the internal affairs doctrine. The exclusive forum provision does not apply to actions arising under the Exchange Act. The amended and restated bylaws will also provide that the federal district courts of the United States of America will be the exclusive forum for the resolution of any complaint asserting a cause of action under the Securities Act. The provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with the Company or its directors, officers or other employees, which may discourage such lawsuits against the Company and its directors, officers and other employees. Alternatively, if a court were to find the choice of forum provision contained in the certificate of incorporation and bylaws to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could materially and adversely affect our business, financial condition and results of operations.

We do not expect to pay any cash dividends in the foreseeable future.

Our current expectation is that we will retain future earnings, if any, to fund the growth of our business as opposed to paying dividends. As a result, capital appreciation, if any, of our common stock will be your sole source of gain, if any, for the foreseeable future.

Our executive officers, directors and principal stockholders have the ability to control or significantly influence all matters submitted to the Company’s stockholders for approval.

Our executive officers, directors and principal stockholders, in the aggregate, beneficially own a significant portion of our outstanding shares of common stock. As a result, if these stockholders were to choose to act together, they would be able to control or significantly influence all matters submitted to our stockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would control or significantly influence the election of directors and approval of any merger, consolidation or sale of all or substantially all of our assets. This concentration of voting power could delay or prevent an acquisition of us on terms that other stockholders may desire.

General Risk Factors

Unfavorable global economic conditions could adversely affect our business, financial condition, stock price and results of operations.

Our results of operations could be adversely affected by general conditions in the global economy and in the global financial markets. For example, a global economic downturn, whether due to terrorism, armed conflict (such as the current conflict between

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Russia and Ukraine), natural disasters or health crises (such as COVID-19) could cause extreme volatility and disruptions in the capital and credit markets. A severe or prolonged economic downturn could result in a variety of risks to our business, including, weakened demand for our product candidates and our ability to raise additional capital when needed on acceptable terms, if at all. A weak or declining economy could also strain our suppliers, possibly resulting in supply disruption, or cause our customers to delay making payments for our services. If the current equity and credit markets deteriorate, it may make any necessary debt or equity financing more difficult, more costly, and more dilutive. Failure to secure any necessary financing in a timely manner and on favorable terms could have a material adverse effect on our growth strategy, financial performance and stock price and could require us to delay or abandon clinical development plans. In addition, there is a risk that one or more of our current service providers, manufacturers and other partners may not survive such difficult economic times, which could directly affect our ability to attain our operating goals on schedule and on budget. Any of the foregoing could harm our business and we cannot anticipate all of the ways in which the current economic climate and financial market conditions could adversely impact our business. Furthermore, our stock price may decline due in part to the volatility of the stock market and any general economic downturn.

If we fail to comply with environmental, health, and safety laws and regulations, we could become subject to fines or penalties or incur costs that could harm our business.

We are subject to numerous environmental, health, and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable materials, including chemicals and biological materials. Our operations also may produce hazardous waste products. We generally anticipate contracting with third parties for the disposal of these materials and wastes. We will not be able to eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from any use by us of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties for failure to comply with such laws and regulations.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, this insurance may not provide adequate coverage against potential liabilities.

In addition, we may incur substantial costs in order to comply with current or future environmental, health, and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Our failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

We or the third parties upon whom we depend may be adversely affected by natural disasters and other calamities, including pandemics, such as the global outbreak of COVID-19, and our business continuity and disaster recovery plans may not adequately protect us from a serious disaster.

Natural disasters could severely disrupt our operations and have a material adverse effect on our business, results of operations, financial condition and prospects. If a natural disaster, fire, hurricane, power outage or other event occurred that prevented us from using all or a significant portion of our headquarters or other offices, that damaged critical infrastructure, such as our suppliers’ manufacturing facilities, or that otherwise disrupted operations, such as data storage, it may be difficult or, in certain cases, impossible for us to continue our business for a substantial period of time.

Occurrences of epidemics or pandemics, depending on their scale, may cause different degrees of damage to the national and local economies within our geographic focus. Global economic conditions may be disrupted by widespread outbreaks of infectious or contagious diseases, and such disruption may adversely affect clinical development plans. For example, the COVID-19 pandemic could have an adverse effect on the coordination of research and development, our capital raising efforts, and the financial condition of our business, as well as the ability of us to retain key personnel and continue to expand product candidate development and conduct clinical trials. In addition, the impact of COVID-19 is likely to cause substantial changes in consumer behavior and has caused restrictions on business and individual activities, which have are likely to continue to lead to reduced economic activity. Extraordinary actions taken by international, federal, state and local public health and governmental authorities to contain and combat the outbreak and spread of COVID-19 in regions throughout the world, including travel bans, quarantines, “stay-at-home” orders and similar mandates for many individuals and businesses to substantially restrict daily activities could have an adverse effect on our financial condition and ability to raise financing.

The disaster recovery and business continuity plans we have in place may prove inadequate in the event of a serious disaster or similar event. We may incur substantial expenses as a result of the limited nature of our disaster recovery and business continuity plans, which could have a material adverse effect on our business. As a result of the COVID-19 pandemic, we may experience reduction in research and development, clinical testing, regulatory compliance activities, and manufacturing activities, and are unable at this time to estimate the extent of the effect of COVID-19 on our business. Further, the extent and duration of the economic slowdown or other adverse effects attributable to COVID-19 remain uncertain at this time. A continued significant economic

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slowdown could have a substantial adverse effect on our financial condition, liquidity, and results of operations. If these conditions persist for an extended term, it could have a material adverse effect on our future revenue and sales.

We have broad discretion in the use of our cash and cash equivalents and may invest or spend the proceeds in ways with which you do not agree and in ways that may not increase the value of your investment.

We have broad discretion over the use of our cash and cash equivalents. You may not agree with our decisions, and our use of the proceeds may not yield any return on your investment. Our failure to apply these resources effectively could compromise our ability to pursue our growth strategy and we might not be able to yield a significant return, if any, on our investment of these net proceeds. You may not have the opportunity to influence our decisions on how to use our cash resources.

We must attract and retain highly skilled employees to succeed.

To succeed, we must recruit, retain, manage and motivate qualified clinical, scientific, technical and management personnel, and we face significant competition for experienced personnel. If we do not succeed in attracting and retaining qualified personnel, particularly at the management level, it could adversely affect our ability to execute our business plan, harm our results of operations and increase our capabilities to successfully commercialize atrasentan and other product candidates. In particular, we believe that our future success is highly dependent upon the contributions of our senior management, particularly our President and Chief Executive Officer, Eric Dobmeier. The loss of services of Mr. Dobmeier or any of our senior management could delay or prevent the successful development of our product pipeline, completion of our clinical trials or the commercialization of our product candidates, if approved. The competition for qualified personnel in the biotechnology field is intense and as a result, we may be unable to continue to attract and retain qualified personnel necessary for the development of our business or to recruit suitable replacement personnel.

Many of the other biotechnology companies that we compete against for qualified personnel have greater financial and other resources, different risk profiles and a longer history in the industry than we do. They also may provide more diverse opportunities and better chances for career advancement. Some of these characteristics may be more appealing to high-quality candidates than what we have to offer. If we are unable to continue to attract and retain high-quality personnel, the rate and success at which we can discover and develop product candidates and our business will be limited.

If equity research analysts do not publish research or reports, or publish unfavorable research or reports, about the company, its business or its market, its stock price and trading volume could decline.

The trading market for our common stock will be influenced by the research and reports that equity research analysts publish about us and our business. Equity research analysts may elect not to provide research coverage of our common stock, and such lack of research coverage may adversely affect the market price of our common stock. In the event we do have equity research analyst coverage, we will not have any control over the analysts or the content and opinions included in their reports. The price of our common stock could decline if one or more equity research analysts downgrade our stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of us or fails to publish reports on it regularly, demand for our common stock could decrease, which in turn could cause its stock price or trading volume to decline.

Our internal computer and information systems, or those used by our CROs, CMOs or other contractors or consultants, may fail or suffer security incidents (e.g., cyber-attacks), which could result in a material disruption of our development programs and may result in extensive and costly legal compliance requirements.

Despite the implementation of appropriate security measures, our internal computer and information systems and those of our current and any future CROs, CMOs and other contractors or consultants may become vulnerable to damage from security incidents (such as data breaches, viruses or other malicious code, coordinated attacks, data loss, phishing attacks, ransomware, denial of service attacks, or other security or information technology incidents caused by threat actors, technological vulnerabilities or human error), unauthorized access, natural disasters, terrorism, war and telecommunication and electrical failures. If such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our development programs and our business operations, whether due to a loss of our trade secrets or other proprietary information or other similar disruptions. For example, the loss of data from completed or future preclinical studies or clinical trials could result in significant delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liability, our competitive position could be harmed and the further development and commercialization of our product candidates could be significantly delayed. System failures or outages, including any potential disruptions due to significantly increased global demand on certain cloud-based systems during the COVID-19 pandemic, could compromise our ability to perform our day-to-day operations, which could harm our ability to conduct business or delay our financial reporting. Such failures could materially adversely affect our operating results and financial condition.

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Although we devote resources designed to protect our information systems, we realize that cyberattacks resulting in a security incident are a threat, and there can be no assurance of our efforts will prevent information security breaches that would result in business, legal, financial, or reputational harm to the Company, or would have a material adverse effect on our results of operations and financial condition. A successful cyberattack could cause serious negative consequences for us, including, without limitation, the disruption of operations, the misappropriation of confidential business information, including personal and financial information, trade secrets, financial loss and the disclosure of corporate strategic plans. The COVID-19 pandemic is generally increasing the attack surface available to criminals, as more companies and individuals work online and work remotely, and as such, the risk of a cybersecurity incident potentially occurring, and our investment in risk mitigations against such an incident, is increasing.

Federal, state, and foreign government requirements include obligations of companies to notify regulators and/or individuals of security breaches involving personally identifiable information, which could result from breaches experienced by us or by our vendors, contractors, or organizations with which we have formed strategic relationships. Even though we may have contractual protections with such vendors, contractors, or other organizations, notifications and follow-up actions related to a security breach could impact our reputation and cause us to incur significant costs. Any failure to prevent or mitigate security breaches or improper access to, use, disclosure or other misappropriation of our data or consumers’ personal data could result in significant legal liability, such as under state breach notification laws, federal law (including HIPAA/HITECH), and international law (e.g., GDPR). Compliance with these and any other applicable privacy and data security laws and regulations is a rigorous and time-intensive process, and we may be required to put in place additional mechanisms ensuring compliance with the new data protection rules and possible government oversight.  Our failure to comply with such laws or to adequately secure the information we hold could result in significant liability or reputational harm and, in turn, a material adverse effect on our future client base, member base and revenue.

We are subject to a variety of privacy and data security laws, and our failure to comply with them could harm our business.

We maintain a large quantity of sensitive information, including confidential business and patient health information in connection with our preclinical and clinical studies, and are subject to laws and regulations governing the privacy and security of such information. Privacy laws, rules and regulations evolve frequently, and their scope may continually change through new legislation, amendments to existing legislation, and changes in enforcement, and may be inconsistent from one jurisdiction to another. The interpretation and application of consumer, health-related and data protection laws, especially with respect to genetic samples and data, in the United States, the European Union and elsewhere, are often uncertain, contradictory and in flux. We cannot provide assurance that current or future legislation will not prevent us from generating or maintaining personal data or that patients will consent to the use of their personal data (as necessary); either of these circumstances may prevent us from undertaking or publishing essential research and development, manufacturing, and commercialization, which could have a material adverse effect on our business, results of operations, financial condition and prospects. Complying with these various laws and regulations could cause us to incur substantial costs or require us to change our business practices, systems, and compliance procedures in a manner adverse to our business. Any violations of these rules by us could subject us to civil and criminal penalties and adverse publicity and could harm our ability to initiate and complete clinical trials.

In the United States, there are numerous federal and state privacy and data security laws and regulations governing the collection, use, disclosure and protection of personal information, including health information privacy laws, security breach notification laws, and consumer protection laws. We may obtain health information from third parties (including research institutions from which we obtain clinical trial data) that are subject to privacy and security requirements under HIPAA/HITECH. Entities that are found to be in violation of HIPAA/HITECH as the result of a breach of unsecured protected health information, a complaint about privacy practices or an audit by HHS, may be subject to significant civil, criminal, and administrative fines and penalties and/or additional reporting and oversight obligations if required to enter into a resolution agreement and corrective action plan with HHS to settle allegations of HIPAA non-compliance. Further, entities that knowingly obtain, use, or disclose individually identifiable health information maintained by a HIPAA covered entity in a manner that is not authorized or permitted by HIPAA may be subject to criminal penalties. Additionally, governmental agencies like the FTC have adopted, or are considering adopting, laws and regulations concerning personal data and data security. The FTC may also take action against companies for unfair acts or practices for failing to keep promises made in public statements, such as privacy policies. We make public statements about our use and disclosure of personal data through our privacy policy, information described on our website, and in press statements. Although we endeavor to ensure that our public statements are complete and accurate, any failure (real or perceived) by us to comply with our privacy commitments could be considered an “unfair and deceptive” act by the FTC resulting in an FTC consent decree that may include fines and sustained government-mandated audits for a period of 20 years. State Attorneys General may enforce comparable state law statutes covering unfair and deceptive practices with similar resulting consequences.

Certain states have also adopted comparable privacy and security laws and regulations, some of which may be more stringent than HIPAA. California recently enacted legislation, the CCPA, which went into effect January 1, 2020. The CCPA, among other things, creates new data privacy obligations for covered companies and provides new privacy rights to California residents, including the right to opt out of certain disclosures of their information and receive detailed information about how their personal information is used. The CCPA provides for civil penalties for violations, as well as a private right of action for data breaches that is expected to increase data breach litigation. The CCPA may increase our compliance costs and potential liability. A ballot initiative from privacy

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rights advocates intended to augment and expand the CCPA called the California Privacy Rights Act, or CPRA, was passed in November 2020 and will take effect in January 2023 (with a look back to January 2022). The CPRA will significantly modify the CCPA, including by expanding consumers’ rights with respect to certain sensitive personal data. The CPRA also creates a new state agency that will be vested with authority to implement and enforce the CCPA and the CPRA. Potential uncertainty surrounding the CCPA and CPRA may increase our compliance costs and potential liability, particularly in the event of a data breach, and could have a material adverse effect on our business. Other states have followed California’s lead. The Virginia Consumer Data Protection Act, or VCDPA, which will go into effect in 2023, gives new data protection rights to Virginia residents and imposes additional obligations on controllers and processors of personal data. Colorado has also adopted a new state data protection act titled the Colorado Privacy Act, which is set to take effect on July 1, 2023. As of January 2022, fourteen states have pending consumer privacy legislation under review, which if enacted would add additional costs and expense of resources to maintain compliance.

In Canada, the Personal Information Protection and Electronic Documents Act, or PIPEDA, and similar provincial laws may impose obligations with respect to processing personal information, including health-related information. PIPEDA requires companies to obtain an individual’s consent when collecting, using, or disclosing that individual’s personal information. Individuals have the right to access and challenge the accuracy of their personal information held by an organization, and personal information may only be used for the purposes for which it was collected. If an organization intends to use personal information for another purpose, it must again obtain that individual’s consent. Failure to comply with PIPEDA could result in significant fines and penalties.

In May 2018, the General Data Protection Regulation, or the GDPR, took effect in the European Economic Area, the EEA. The GDPR governs the collection, use, disclosure, transfer, or other processing of personal data of natural persons. Among other things, the GDPR imposes strict obligations on the ability to process health-related and other personal data of data subjects in the EEA, including in relation to use, collection, analysis, and transfer (including cross-border transfer) of such personal data. The GDPR includes requirements relating to the consent of the individuals to whom the personal data relates, including detailed notices for clinical trial subjects and investigators. The GDPR also includes certain requirements regarding the security of personal data and notification of data processing obligations or security incidents to appropriate data protection authorities or data subjects as well as requirements for establishing a lawful basis on which personal data can be processed and a right to lodge a complaint with the government.

The GDPR, as well as law in the UK and Switzerland, also prohibits the international transfer of personal data from the EEA/UK/Switzerland to countries outside of those jurisdictions unless made to a country deemed to have adequate data privacy laws by the European Commission or where a data transfer mechanism has been put in place. We rely on a mixture of mechanisms to transfer personal data to countries outside of the EEA, Switzerland, and the UK, including to the United States and therefore are continuing to evaluate the guidance and mechanisms required to establish adequate safeguards for personal data. Until recently, one such data transfer mechanism was the EU-US Privacy Shield. However, in July 2020 the Court of Justice of the European Union, or CJEU, declared the Privacy Shield to be invalid. The CJEU upheld the validity of the standard contractual clauses, or SCCs, as a legal mechanism to transfer personal data but companies relying on SCCs will continually be subject to guidance from regulators in the EEA and need to evaluate and implement supplementary measures that provide privacy protections additional to those provided under SCCs. In turn, the findings of the CJEU will have significant implications for cross-border data flows. On June 4, 2021, the European Commission adopted new SCCs to apply to international transfers. We will have until December 27, 2022 to update any existing agreements, or any new agreements executed before September 27, 2021, that rely on the former SCCs. If we are otherwise unable to transfer personal data between and among countries and regions in which we operate, it could affect the manner in which we conduct our operations, and we may find it necessary to establish systems in the EEA, Switzerland, and the UK to maintain personal data originating from the EEA and the UK, which may involve substantial expense and distraction from other aspects of our business. As supervisory authorities continue to issue further guidance on personal data export mechanisms, including circumstances where the SCCs cannot be used and/or what safeguards must be implemented, or start taking enforcement action, there will be uncertainty as to how we comply with EEA, Switzerland, and UK privacy laws and we could suffer additional costs, complaints, or regulatory investigations or fines. We may need to implement additional safeguards to further enhance the security of data transferred out of the EEA/Switzerland/UK, conduct data transfer impact assessments, and review existing agreements which could increase our compliance costs, expose us to further regulatory scrutiny and liability, and adversely affect our business. Further, the GDPR provides that countries in the EEA may establish their own laws and regulations further restricting the processing of certain personal data, including genetic data, biometric data, and health data.

Companies that must comply with the GDPR face increased compliance obligations and risk, including more robust regulatory enforcement of data protection requirements and potential fines for noncompliance of up to €20 million or 4 percent of the annual global revenues of the noncompliant company, whichever is greater. Additionally, following the UK’s withdrawal from the EU and the EEA, companies must comply with the GDPR and the GDPR as incorporated into UK national law, the latter regime having the ability to separately fine up to the greater of £17.5 million or 4 percent of global turnover.

We create contractual obligations with third parties with whom we depend in relation to the operation of our business, a number of which process personal data on our behalf. With each such provider we attempt to mitigate the associated risks of using third parties

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by performing security assessments and detailed due diligence, entering into contractual arrangements to ensure that providers only process personal data according to our instructions, and that they have sufficient technical and organizational security measures in place. Where we transfer personal data outside the EEA, the UK, or Switzerland to such third parties, we do so while considering the relevant data export requirements, as described above. There is no assurance that these contractual measures and our own privacy and security-related safeguards will protect us from the risks associated with the third-party processing, storage, and transmission of such information. Any violation of data or security laws by our third-party processors could have a material adverse effect on our business and result in the fines and penalties outlined above.

If our operations are found to be in violation of any of the privacy and data protection laws described above or any other laws that apply to us, we may be subject to penalties, including, but not limited to, criminal, civil and administrative penalties, damages, fines, disgorgement, individual imprisonment, possible exclusion from participation in government healthcare programs, injunctions, private qui tam actions brought by individual whistleblowers in the name of the government, class action litigation and the curtailment or restructuring of our operations, as well as additional reporting obligations and oversight if we become subject to a corrective action plan or other agreement to resolve allegations of non-compliance with these laws, any of which could adversely affect our ability to operate our business and our results of operations. When such events occur (or even alleged), our reputation may be harmed, we may lose current and potential users and the competitive positions of our brand might be diminished, any or all of which could materially adversely affect our business, reputation, operating results, and financial condition.

U.S. federal income tax reform and changes in other tax laws could adversely affect us.

In December 2017, the TCJA, was signed into law, significantly reforming the Code. The TCJA, among other things, includes changes to U.S. federal tax rates, imposes significant additional limitations on the deductibility of business interest, allows for the expensing of capital expenditures, puts into effect the migration from a “worldwide” system of taxation to a partial “territorial” system, and modifies or repeals many business deductions and credits.

In addition, new legislation or regulation which could affect our tax burden could be enacted by any governmental authority. We cannot predict the timing or extent of such tax-related developments which could have a negative impact on our financial results. Additionally, we use our best judgment in attempting to quantify and reserve for these tax obligations. However, a challenge by a taxing authority, our ability to utilize tax benefits such as carryforwards or tax credits, or a deviation from other tax-related assumptions could have a material adverse effect on our business, results of operations or financial condition.

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Item 1B. Unresolved Staff Comments.

None.

Item 2. Properties.

In connection with the Merger in 2020, we assumed a facility lease for an office and laboratory facility in Berkeley, California totaling approximately 111,000 square feet that has a remaining lease term expiring on December 31, 2029. We have the right to further extend the lease term for up to two renewal terms of five years each, provided that the rental rate would be subject to market adjustment at the beginning of each renewal term. We are subleasing approximately 95,000 square feet of the Berkeley facility as of December 31, 2021 under a sublease agreement, which ultimately will cover the entire leased premises, and which expires at the same time as the underlying lease.

In addition, we lease approximately 23,000 square feet of office space in Vancouver, Canada for which the expiration date is August 31, 2027.

In June 2021, we entered into a sublease agreement for approximately 26,000 square feet of office space located in Seattle, Washington, which we are using for our corporate headquarters, and that has a remaining lease term expiring April 30, 2026.

We believe that our existing facilities are adequate to meet our current needs, and that suitable additional or alternative spaces will be available in the future on commercially reasonable terms.

Item 3. Legal Proceedings.

We are not currently subject to any material legal proceedings.

Item 4. Mine Safety Disclosures.

Not applicable.

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PART II

Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.

Market Price of Common Stock

Our common stock is traded on the Nasdaq Global Select Market under the symbol “KDNY.” From April 15, 2015 to October 5, 2020 our common stock was traded under the symbol “ADRO.”

On March 10, 2022, the last reported sale price of our common stock on the Nasdaq Global Select Market was $13.00 per share.

Holders of Record

As of March 10, 2022, we had 99 holders of record of our common stock. The actual number of stockholders is greater than this number of record holders, and includes stockholders who are beneficial owners, but whose shares are held in street name by brokers and other nominees. This number of holders of record also does not include stockholders whose shares may be held in trust by other entities.

Dividend Policy

We have never declared or paid cash dividends on our capital stock. We intend to retain all available funds and any future earnings, if any, to fund the development and expansion of our business and we do not anticipate paying any cash dividends in the foreseeable future. Any future determination related to dividend policy will be made at the discretion of our board of directors.

Recent Sales of Unregistered Securities

None.

Repurchases of Shares or of Company Equity Securities

None.

Item 6. [Reserved]

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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations together with our consolidated financial statements included elsewhere in this Annual Report on Form 10-K. This discussion and other parts of this report contain forward-looking statements that involve risk and uncertainties, such as statements of our plans, objectives, expectations and intentions. As a result of many factors, including those factors set forth in the “Risk Factors” section of this report, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

We are a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing precision medicines for kidney diseases. Our pipeline is focused on rare, severe chronic kidney diseases with well-defined clinical pathways. Our lead clinical program is atrasentan, an endothelin A receptor antagonist. In March 2021 we initiated the phase 3 ALIGN trial of atrasentan for IgA nephropathy, or IgAN, and in April 2021 we initiated the phase 2 AFFINITY basket trial for proteinuric glomerular diseases. Our second product candidate, BION-1301, is an anti-APRIL monoclonal antibody also in development for patients with IgAN, and we presented results from the ongoing phase 1/2 trial at the American Society of Nephrology (ASN) Kidney Week in November 2021. We plan to maintain commercial rights for atrasentan and BION-1301 in North America and possibly Europe. In November 2021, we also established SanReno, a joint venture to develop, manufacture and commercialize kidney disease therapies in the Territory. East-Asian populations have a higher incidence and prevalence of IgAN than in the United States and Europe.  We believe that a strong local presence in East-Asia may allow us to accelerate the clinical development and maximize the commercial potential of atrasentan and BION-1301 in the region. We are also advancing our third program, CHK-336 towards an expected start of a phase 1 clinical trial in healthy volunteers in the first half of 2022. We are developing CHK-336 for the treatment of primary hyperoxaluria, or PH, as well as secondary hyperoxaluria and idiopathic kidney stone formation. In addition, we are conducting research programs in several other rare, severe chronic kidney diseases. We seek to build our pipeline by leveraging insights from kidney single cell RNA sequencing, human-derived organoids and new translational models, to discover and develop therapeutic candidates with mechanisms of action targeted against key kidney disease pathways. To support these efforts, we have entered into a strategic collaboration with Evotec SE, or Evotec, to jointly identify, characterize and validate novel mechanisms and discover precision medicines for lupus nephritis, IgAN, polycystic kidney disease, or PKD, and other primary glomerular diseases. The collaboration with Evotec will also involve further characterization of pathways and patient stratification strategies for programs currently in Chinook’s clinical and preclinical pipeline.

Our approach to precision medicines leverages recent advances in identifying targeted kidney therapies linked to mechanistic biomarkers by the application of systems biology approaches in nephrology. The application of systems biology to nephrology has advanced over the past decade through the study of multiple patient groups across a wide variety of kidney diseases and their associated multilevel data sets, including genome, transcriptome, proteome, metabolome, pathology and prospective long-term clinical characteristics and outcomes. A key objective of these investigations is to define kidney diseases in molecular terms to drive the development of targeted treatments. We believe we are well-positioned to exploit the insights provided into the key molecular drivers and classifiers of kidney diseases by the application of these systems biology tools to nephrology. Our strategy is to use these mechanistic insights to select compelling drug targets and deliver novel and differentiated product candidates for rare and severe kidney diseases with high unmet medical need.

For additional information regarding our product candidates, clinical development candidates and other research and discovery programs, refer to “Overview” within Part I, Item 1. Business in this Annual Report on Form 10-K.

Components of Operating Results

Collaboration and License Revenue

We have not generated any revenue from product sales. Our revenue to date has been primarily derived from our collaboration and license agreements.

SanReno Therapeutics

In November 2021, we entered into a License Agreement with SanReno, or the China License Agreement. The China License Agreement includes the transfer of intellectual property rights in the form of a development and commercialization license in the Territory; manufacturing and supply services; and participation in opt-in global studies with the collaboration party. In exchange for the development and commercialization license, we received non-cash consideration in the form of preferred shares in SanReno. The terms of the China License Agreement also include potential payment to us for the following: progress-dependent milestone payment; royalties on the net sales of a licensed product and reimbursement for certain expenses incurred. As of December 31, 2021, these potential payments are not considered probable of being achieved and they relate to promised goods or services for which revenue will be recognized upon our satisfaction of the underlying performance obligations.

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Pre-existing Collaboration Agreements

Prior to the completion of the Merger, Aduro generated revenue from collaboration and license agreements. These collaboration agreements may have included the transfer of intellectual property rights in the form of licenses, promises to provide research and development services and promises to participate on certain development committees with the collaboration party. The terms of such agreements included payment to Aduro of one or more of the following: nonrefundable upfront fees, payment for research and development services, development, regulatory and commercial milestone payments, and royalties on net sales of licensed products.

Potential milestone payments related to development, regulatory or commercial milestone payments may be earned in the future under these pre-existing agreements, but all such payments are uncertain and beyond our or our collaborators’ control and would be recorded as revenue upon receipt or over a period following receipt, such as under the CAPM model, if and when such payments are earned. We evaluated the remaining performance obligations under these pre-existing agreements and concluded that we do not expect to recognize material revenue under these pre-existing agreements in the near term.

For additional information, refer to Note 11 “Collaboration and License Agreements” of the Notes to the Consolidated Financial Statements under Part II, Item 8, “Financial Statements and Supplementary Data” in this Annual Report on Form 10-K.

Research and Development Expenses

The largest component of our operating expenses is our investment in research and development activities, including the clinical development of our product candidates. Research and development expenses represent costs incurred to conduct research, such as the discovery and development of our product candidates, as well as the development of product candidates pursuant to Aduro’s pre-existing collaboration and license agreements. Research and development costs include employee-related costs; licensing costs; materials and supplies; contracted research and manufacturing; consulting arrangements; allocated costs, such as facility costs; and other expenses incurred to advance our research and development activities. We recognize all research and development costs as they are incurred. Clinical trial costs, contract manufacturing and other development costs incurred by third parties are expensed as the contracted work is performed.

We expect our research and development expenses to increase in the future as we advance our product candidates into and through clinical trials and pursue regulatory approval of our product candidates. The process of conducting the necessary clinical research to obtain regulatory approval is costly and time-consuming. The probability of success for our product candidates and technologies may be affected by a variety of factors including: the quality of our product candidates, early clinical data, investment in our clinical programs, competition, manufacturing capability and commercial viability. We may never succeed in obtaining regulatory approval for any of our product candidates. As a result of the uncertainties discussed above, we are unable to determine the duration and completion costs of our research and development projects or when and to what extent we will generate revenue from the commercialization and sale of our product candidates.

General and Administrative Expenses

General and administrative expenses include employee-related costs, expenses for outside professional services, and other allocated expenses. Employee-related costs consist of salaries, bonuses, severance and benefits. Consulting and outside services consist of legal, accounting and audit services, insurance expenses, investor relations activities, administrative services and other consulting fees. Allocated expenses consist of rent expense related to our offices and research and development facility.

Change in Fair Value of Contingent Consideration and Contingent Value Rights Liabilities

At the effective time of the Merger, we also entered into an agreement, or CVR Agreement, pursuant to which Aduro’s common stockholders of record as of the close of business on October 2, 2020 received one CVR for each outstanding share of Aduro common stock held by such stockholder on such date. Each CVR represents the contractual right to receive payments from us upon the receipt of consideration resulting from milestones and royalties from certain pre-existing agreements and the disposition or licensing of any of Aduro’s non-renal assets, net of deductions permitted under the CVR Agreement, including taxes and certain other expenses. Change in the fair value of the contingent consideration and CVR liabilities at each reporting consists of the changes in the values of these contractual rights.

Amortization of Intangible Assets

Amortization of intangible assets, excluding goodwill results from the amortization of finite-lived intangible assets acquired in the Merger. Amortization is over a period of 9 to 17 years, with an original weighted average period of 16.7 years.

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Gain on Sale of Assets to Equity Method Investment

In 2021, we entered into an agreement with Sairopa B.V., or Sairopa, to acquire certain of our non-renal assets in exchange for preferred stock in Sairopa. The sale of the non-renal assets to Sairopa resulted in a $7.2 million gain, which is the difference between the fair value of the equity received and the carrying value of the non-renal assets sold. The gain is reported in our consolidated statements of operations and comprehensive loss during the year ended December 31, 2021.

Other Income (Expense), Net

Other income (expense), net consists primarily of interest income and expense, foreign currency gains and losses, and various income or expense items of a non-recurring nature.

Change in Fair Value of Redeemable Convertible Preferred Stock Tranche Liability

As a private company, we issued Series A redeemable convertible preferred stock (Series A stock). The terms of the Series A stock agreement included provisions requiring the investors to purchase, and obligating the Company to deliver, additional shares of redeemable convertible preferred stock at a specified price in the future based on the achievement of certain development-based milestones.

We estimated the fair value of the redeemable convertible preferred stock tranche liability related to each milestone utilizing the income approach using unobservable inputs including (a) future per share value of Series A stock upon achievement of the milestone, (b) estimated term until date of milestone achievement, and (c) probability of milestone achievement. The future per share value of Series A stock upon achievement of the milestone and the probability of milestone achievement for each tranche were calculated on a probability-weighted basis giving equal weighting to public offering and private exit scenarios. The future cash flows were discounted to their fair values as of the valuation date using one or more discount rates, depending on the number of probability-weighted scenarios employed.

Upon issuance, the fair value of the redeemable convertible preferred stock tranche liability was recorded as a reduction in the amounts paid by investors for the purchase of Series A stock.

Upon closing of the Merger, the outstanding redeemable convertible preferred stock tranche rights terminated pursuant to the terms of the Merger agreement.

Income Tax (Expense) Benefit

We are subject to income taxes in the United States and foreign jurisdictions in which we do business. These foreign jurisdictions have statutory tax rates different from those in the United States. Accordingly, our effective tax rates will vary depending on the relative proportion of foreign to U.S. income, the availability of research and development tax credits, changes in the valuation of our deferred tax assets and liabilities and changes in tax laws. We regularly assess the likelihood of adverse outcomes resulting from the examination of our tax returns by the Internal Revenue Service, or IRS, and other tax authorities to determine the adequacy of our income tax reserves and expense. Should actual events or results differ from our current expectations, charges or credits to our income tax expense may become necessary.

Share of Net Loss of Equity Method Investment

Share of net loss of equity method investment represents our share of net loss of the Sairopa investment, which is reported in our consolidated statements of operations and comprehensive loss on a one quarter lag.

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Results of Operations

Comparison of the Years Ended December 31, 2021 and 2020

Collaboration and License Revenue

Total revenue was $51.6 million for the year ended December 31, 2021, an increase of $50.8 million compared to $0.8 million for the year ended December 31, 2020. The increase in revenue was primarily due to $41.2 million of non-cash revenue recognized under our license agreement with SanReno and a development milestone of $10.0 million recognized under our agreement with Merck and Co, Inc., or Merck. The agreement with Merck was acquired through the Merger. For additional information, refer to Note 11 “Collaboration and License Agreements”.

Research and Development Expenses

The following tables summarize our research and development expenses by program and by category incurred during the years ended December 31, 2021 and 2020.

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Research and development expenses were $97.0 million for the year ended December 31, 2021, an increase of $60.9 million compared to $36.1 million for the year ended December 31, 2020. The increase in research and development expenses was primarily due to external clinical and manufacturing expenses related to the atrasentan and BION-1301 clinical programs; higher employee-related costs, including salaries, benefits and stock-based compensation expense, associated with hiring staff to build out our clinical and development capabilities; increased spending for consulting and outside services; and higher facilities and other costs. The year ended December 31, 2021 also includes an upfront fee of $3.3 million paid to Evotec International GmbH under a research collaboration and license agreement entered into in February 2021.

General and Administrative Expenses

The following table summarizes our general and administrative expenses incurred during the years ended December 31, 2021 and 2020:

General and administrative expenses were $31.9 million for the year ended December 31, 2021, an increase of $12.8 million compared to $19.1 million for the year ended December 31, 2020. The increase in general and administrative expenses was primarily due to higher employee-related costs, including salaries, benefits and stock-based compensation expense associated with the addition of administrative staff to build out our public company infrastructure; higher legal, consulting and other professional services costs; and an increase in facilities and other costs.

Change in fair value of contingent consideration and contingent value rights liabilities

Change in fair value of contingent consideration and contingent value rights liabilities expense was $27.3 million for the year ended December 31, 2021, an increase of $25.8 million compared to $1.5 million for the year ended December 31, 2020. The increase primarily resulted from a change in estimate of the potential future proceeds derived from Aduro’s license agreement with Merck and from the sale of certain of our non-renal assets in exchange for preferred shares in Sairopa during the second quarter of 2021. The fair value of the contingent value rights liability also increased during 2021 due to the achievement of a development milestone under the terms of the agreement with Merck, which is payable to the CVR holders, net of permitted deductions. During the second quarter of 2021, Merck informed us that they intend to explore the potential benefits of the product candidate MK-5890, previously out-licensed to Merck by Aduro, in a phase 2 clinical study for a new indication. This could result in potential milestone and royalty payments for the benefit of the CVR holders.

Amortization of intangible assets

Amortization of intangible assets expense increased by $1.3 million for the year ended December 31, 2021 compared to the year ended December 31, 2020 due to amortization of finite-lived intangible assets acquired in the Merger during the fourth quarter of 2020.

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Gain on sale of assets to equity method investment

Gain on sale of assets to equity method investment increased $7.2 million for the year ended December 31, 2021, resulting from the sale of certain non-renal assets in exchange for stock in Sairopa during the second quarter of 2021. The gain is the difference between the fair value of the equity received and the carrying value of the non-renal assets sold.

Change in fair value of redeemable convertible preferred stock tranche liability

Change in fair value of redeemable convertible preferred stock tranche liability decreased by $27.7 million for the year ended December 31, 2021 compared to the year ended December 31, 2020, due to the termination of the convertible preferred stock tranche rights pursuant to the terms of the Merger agreement.

Income tax (expense) benefit

We recorded income tax expense of $2.1 million for the year ended December 31, 2021, primarily resulting from the reduction of deferred tax liabilities related to our foreign entities.

Share of net loss of equity method investment

Share of net loss of equity method investment increased by $1.6 million for the year ended December 31, 2021 compared to the year ended December 31, 2020, resulting from our share of net loss of the Sairopa investment, net of any taxes.

Liquidity and Capital Resources

Sources of Liquidity

As of December 31, 2021, we had $355.1 million in cash, cash equivalents and marketable securities. We expect that our research and development and general and administrative expenses will increase, and, as a result, we anticipate that we will continue to incur increasing losses in the foreseeable future. We believe that our cash, cash equivalents and marketable securities as of December 31, 2021 will enable us to fund our operating expenses and capital expenditure requirements for at least the next 24 months.

In November 2021, we completed an underwritten public offering of 9.5 million shares of our common stock at a price to the public of $14.00 per share, which included the exercise in full of the underwriters’ option to purchase an additional 1.7 million shares of our common stock. In addition, we sold to certain investors pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to an aggregate of 3.6 million shares of common stock at a purchase price of $13.9999 per pre-funded warrant, which represents the per share public offering price for the common stock less the $0.0001 per share exercise price for each such warrant. The Pre-Funded Warrants are exercisable at any time after the date of issuance and do not expire. A holder of Pre-Funded Warrants may not exercise the warrant if the holder, together with its affiliates, would beneficially own more than 4.99% of the number of shares of common stock outstanding immediately after giving effect to such exercise. A holder of Pre-Funded Warrants may increase or decrease this percentage, but not in excess of 19.99%, by providing at least 61 days’ prior notice to Chinook. The underwritten public offering resulted in gross proceeds to us of $183.5 million, before $11.3 million of transaction costs.

In April 2021, we entered into an “at-the-market” sales agreement (the “2021 Sales Agreement”) with Cantor Fitzgerald & Co. and SVB Leerink LLC, through which we may offer and sell shares of our common stock having an aggregate offering of up to $75.0 million through our sales agents, Cantor Fitzgerald & Co. and SVB Leerink LLC. We will pay the sales agents a commission of up to 3% of the gross proceeds of sales made through the 2021 Sales Agreement. In 2021, we sold 2.2 million shares for net proceeds of $33.9 million under the 2021 Sales Agreement. As of December 31, 2021, we have $40.0 million remaining under the 2021 Sales Agreement.

Funding Requirements

We have not generated any revenue from product sales, and we do not know when, or if, we will generate any revenue from product sales. We do not expect to generate any revenue from product sales unless and until we obtain regulatory approval of and commercialize any of our product candidates. At the same time, we expect our expenses to increase in connection with our ongoing development activities, particularly as we continue the research, development and clinical trials of, and seek regulatory approval for, our product candidates. Accordingly, we anticipate that we will need substantial additional funding in connection with our continuing operations.

Until we can generate a sufficient amount of product revenue to finance our cash requirements, we expect to finance our future cash needs primarily through the issuance of additional equity, borrowings and strategic alliances with partner companies. To the extent that we raise additional capital through the issuance of additional equity, including through our at-the-market offering program or convertible debt securities, the ownership interest of our stockholders will be diluted, and the terms of these securities may include

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liquidation or other preferences that adversely affect the rights of existing stockholders. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through marketing and distribution arrangements or other collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or commercialization efforts or grant rights to develop and market our product candidates to third parties that we would otherwise prefer to develop and market ourselves.

Cash Flows

The following table summarizes our cash flows for the periods indicated:

Operating Activities

Net cash used in operating activities was $102.7 million for the year ended December 31, 2021, an increase of $46.9 million compared to $55.8 million for the year ended December 31, 2020. The increase was primarily due to an increased operating loss resulting from increased research and development and general and administrative spending.     

Investing Activities

Net cash used in investing activities was $112.6 million for the year ended December 31, 2021, an increase of $222.3 million compared to $109.7 million cash provided by investing activities for the year ended December 31, 2020. The increase was primarily due to net purchases of marketable securities during the year ended December 31, 2021. Additionally, cash provided by investing activities in the prior year included the receipt of cash and cash equivalents acquired in connection with the Merger and net proceeds from maturities of marketable securities, with no corresponding amounts during the year ended December 31, 2021.

Financing Activities

Net cash provided by financing activities was $209.5 million for the year ended December 31, 2021, an increase of $85.2 million compared to $124.3 million for the year ended December 31, 2020. The increase was primarily due to aggregate net proceeds of $206.1 million received from the sale of common stock in the November 2021 underwritten public offering and the at-the-market sales agreement; option exercises during the year ended December 31, 2021, which increased over the prior period by $2.1 million; and an increase in proceeds from the employee stock purchase plan. These increases were partially offset by net proceeds from the issuance of redeemable convertible preferred stock in the prior year.

Critical Accounting Policies and Significant Judgments and Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States, or U.S. GAAP. The preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported revenue generated and expenses incurred during the reporting periods. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. We believe that the accounting policies discussed below are critical to understanding our historical and future performance, as these policies relate to the more significant areas involving management’s judgments and estimates.

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Business Combination

Accounting for acquisitions requires extensive use of estimates and judgment to measure the fair value of the identifiable tangible and intangible assets acquired, including in-process research and development and liabilities assumed. Additionally, we must determine whether an acquired entity is considered a business or a set of net assets because the excess of the purchase price over the fair value of net assets acquired can only be recognized as goodwill in a business combination. We accounted for the Merger with Aduro as a business combination under the acquisition method of accounting. Consideration paid to acquire Aduro was measured at fair value and included the exchange of Aduro’s common stock, assumption of Aduro stock options and warrants, and assumption of contingent value rights.

We allocated the purchase price to the acquired tangible and intangible assets and assumed liabilities of Aduro based on their estimated fair values as of the acquisition date. The allocation of the purchase price resulted in recognition of intangible assets related to an acquired license agreement, an in-place sublease broker commission, in-process research and development and goodwill. The fair value of the identifiable intangible assets is based on detailed valuations using information and assumptions such as the timing and estimated costs to complete the in-process projects, projecting regulatory approvals, developing an appropriate discount rate and estimating future cash flows.

Contingent Value Rights and Contingent Consideration Liabilities

The estimated fair value of the contingent value rights and contingent consideration liabilities, initially measured and recorded on the Merger date, are considered to be Level 3 instruments. The contingent value rights and contingent consideration liabilities are recorded at fair value at the end of each reporting period with changes in estimated fair values recorded in change in fair value of contingent consideration and contingent value rights liabilities in the consolidated statements of operations and comprehensive loss. In determining the fair value of the CVR and the contingent consideration liabilities, we used the income approach, primarily discounted cash flow models. The discounted cash flow models require the use of significant judgment, estimates and assumptions, including estimated revenues and costs, the probability of technical and regulatory success, and discount rates.

Intangible Assets

Our intangible assets include an acquired out-license agreement and indefinite-life in-process research and development assets (“IPR&D”) acquired in the Merger with Aduro. The acquired out-license agreement represents the estimated fair value of an agreement with Merck and Co, Inc. (“Merck”) related to a product candidate currently being studied in phase 2 clinical testing. The IPR&D represents the estimated fair value as of the acquisition date of two substantive in-process projects that have not reached technological feasibility: the BION-1301 product candidate currently being tested in a phase 1 clinical trial and the non-renal assets intended to be disposed of. The primary basis for determining technological feasibility of these assets is, in the case of BION-1301 and the Merck agreement, obtaining regulatory approval. In the case of the non-renal assets, it is completing transactions for the out-license or sale of the assets. The fair value of the Merck out-license agreement and in-process BION-1301 research and development intangible assets were determined using probability-weighted discounted cash flow models, including a multi-period excess earnings method and use of a Monte Carlo simulation. Projecting discounted future cash flows requires management to make significant estimates regarding future revenue and expenses, probability of technological and regulatory success, revenue volatility and discount rates. The discount rate used is determined at the time of acquisition and includes a rate of return which accounts for the time value of money, as well as risk factors reflecting the economic risk that the projected cash flows may not be realized. The fair value of the non-renal IPR&D intangible assets were determined using a probability-weighted discounted cash flow model, including assumptions regarding probabilities, timing and prices for the sale or out-license of these assets.

We review our intangible assets at least annually, on October 1 of each year, for possible impairment. Intangible assets are reviewed for possible impairment between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of the assets below their carrying values. Our intangible assets totaled $62.6 million at December 31, 2021.

Research and Development Expenses

Research and development expenses represent costs incurred to conduct research, such as the discovery and development of our product candidates. Research and development costs include employee-related costs; licensing costs, materials and supplies, contracted research and manufacturing, consulting arrangements; allocated costs, such as facility costs; and other expenses incurred to advance our research and development activities. We recognize all research and development costs as they are incurred. In-licensing fees and other costs to acquire technologies that are utilized in research and development, and that are not expected to have alternative future use, are expensed when incurred. Clinical trial costs, contract manufacturing and other development costs incurred by third parties are expensed as the contracted work is performed. For service contracts that include a nonrefundable prepayment for future service, the upfront payment is deferred and recognized in the consolidated statements of operations and comprehensive loss as the services are rendered.

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Estimated Fair Value of Redeemable Convertible Preferred Stock Tranche Liability

We had a liability related to future tranche options for purchase of our Series A redeemable convertible preferred stock. Such redeemable convertible preferred stock tranche rights terminated upon the closing of the Merger. The tranche options were accounted for as a liability at its estimated fair value at the inception of the obligation and was remeasured to fair value as of each balance sheet date, with the related re-measurement adjustment recognized as a component of other income (expense) in the consolidated statements of operations and comprehensive loss. The estimated fair value of the tranche options was determined using an option pricing model that considered the redeemable convertible preferred stock price, the exercise price of the option, the estimated time period the option would have been outstanding, the volatility of the underlying stock, the risk-free interest rate associated with the life of the option, and the dividend yield of the underlying Series A redeemable convertible preferred stock. The value derived from the option pricing model was adjusted for the probability of the related milestones not being met. Our management used its judgment to estimate many of these variables. We recorded adjustments to the estimated fair value of the redeemable convertible preferred stock tranche liability until which time the tranche options expired upon closing of the Merger.

Stock-Based Compensation Expense

We measure and recognize compensation expense for all stock-based awards granted to employees and non-employees based on the estimated fair value of the award on the date of grant.

We use the Black-Scholes option pricing model to measure the fair value of stock option awards when they are granted. We make several estimates in determining stock-based compensation and these estimates generally require significant analysis and judgment to develop, including (i) the expected share price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate and (iv) the expected dividend yield. Prior to the Merger, due to the lack of company-specific historical and implied volatility data, we based our estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded, which have characteristics similar to those of Private Chinook, including stage of product development and focus on the life science industry. For options granted after the Merger, we are using historical volatility of Aduro’s and the Company’s common stock, as it approximates the volatility of the formerly utilized peer group. The historical volatility is calculated based on a period of time commensurate with the expected term assumption. The expected term for options granted to employees represents the weighted-average period the awards are expected to remain outstanding and our estimates were determined using the simplified method. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. We use an assumed dividend yield of zero as we have never paid dividends and have no current plans to pay any dividends on our common stock.

Stock-based compensation expense for restricted stock and stock options is recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective award. We record forfeitures as incurred.

For the years ended December 31, 2021 and 2020, stock-based compensation expense was $12.8 million and $3.6 million, respectively. As of December 31, 2021, we had $34.6 million of total unrecognized stock-based compensation costs, which we expect to recognize over a weighted-average period of 2.5 years.

Revenue Recognition

At inception, we determine whether contracts are within the scope of ASC Topic 606, Revenue from Contracts with Customers (“ASC Topic 606”). For contracts that are determined to be within the scope of ASC Topic 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which we expect to be entitled to receive in exchange for these goods and services, which is determined by applying the following five steps:

We only apply the five-step model to contracts when we determine that collection of substantially all consideration for goods and services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration.

Performance obligations promised in a contract are identified based on the goods and services that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract. To the extent a contract includes multiple promised goods and services, we apply judgment to determine whether promised goods and services are both capable of being distinct and distinct in the context of the contract. If these criteria are not met, the promised goods and services are accounted for as a combined performance obligation.

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Determining the transaction price requires significant judgment. The transaction price in the contract is measured at fair value and reflects the consideration we expect to be entitled to in exchange for the goods and services. In the transaction price, variable consideration is only included to the extent that it is highly probable that a significant future reversal in the amount of cumulative revenue recognized under the contract will not occur. The transaction price is allocated to each performance obligation according to their stand-alone selling prices ("SSP") and is recognized when control of the goods or services are transferred to the customer, either over time or at a point in time, depending on the specific terms and conditions in the contracts. Judgment is required to determine the SSP. In instances where the SSP is not directly observable, such as when a license or service is not sold separately, the SSP is determined using information that may include market conditions and other observable inputs.

In November 2021, we entered into a License Agreement with SanReno (“China License Agreement”). In addition, we assumed several existing collaboration agreements in conjunction with the Merger. These agreements may include the transfer of intellectual property rights in the form of licenses and obligations to provide research and development services, participate on certain development committees with the collaboration party and to provide manufacturing supply. The terms of such agreements generally include payment in the form of cash or equity securities to us for one or more of the following: development and commercialization licenses; research and development services; manufacturing supply; development, regulatory and commercial milestone fees; and royalties on net sales of licensed products. Judgment is required to determine whether the license to our intellectual property is distinct from the research and development services or participation on development committees.

As of the closing of the Merger, we considered all remaining performance obligations under the assumed agreements to determine appropriate revenue recognition. For agreements that include development, regulatory or commercial milestone payments, we evaluated whether the milestones are considered probable of being reached and concluded that all such milestones are not within the control of us or the licensee, such as regulatory approvals, and are not considered probable of being achieved until those approvals are received or the underlying activity has been completed. Accordingly, any future milestone payments received under the assumed agreements will be analogized to ASC Topic 606 and recorded as revenue upon or over a period following receipt, if such milestone payments are received.

We also assumed an existing out-license agreement with Merck under which all performance obligations of Aduro were completed prior to the Merger. We are eligible to receive future contingent payments pursuant to Merck’s achievement of certain development, commercial and net sales milestones for a product candidate. In addition, we are eligible to receive royalties based on net sales of the product. Any such milestones and royalties earned will be payable by us to the CVR holders, net of deductions permitted under the CVR Agreement, including taxes and certain other expenses.

Income Taxes

Income taxes are accounted for using an asset and liability approach that requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the consolidated financial statement and tax bases of assets and liabilities at the applicable enacted tax rates. We establish a valuation allowance for deferred tax assets if it is more likely than not that these items will expire before we are able to realize its benefits or that future deductibility is uncertain.

We recognize the tax benefit from uncertain tax positions only if it is more likely than not that the tax position will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax position is measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement. We recognize interest and penalties related to income tax matters in income tax expense if incurred.

Recent Accounting Pronouncements

For information regarding recent accounting pronouncements, refer to Note 2 “Summary of Significant Accounting Policies” of the Notes to the Consolidated Financial Statements under Part II, Item 8 of this report.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

A smaller reporting company is not required to provide the information required by this Item.

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Item 8. Financial Statements and Supplementary Data.

CHINOOK THERAPEUTICS, INC.

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

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Report of Independent Registered Public Accounting Firm

To the Board of Directors and Stockholders of Chinook Therapeutics, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Chinook Therapeutics, Inc. and its subsidiaries (the “Company”) as of December 31, 2021 and 2020, and the related consolidated statements of operations and comprehensive loss, of redeemable convertible preferred stock and stockholders’ equity (deficit) and of cash flows for the years then ended, including the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2021 and 2020, and the results of its operations and its cash flows for the years then ended in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s consolidated financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these consolidated financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that (i) relates to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Valuation of the Contingent Value Rights and Contingent Consideration Liabilities

As described in Notes 2, 3, and 5 to the consolidated financial statements, the Company completed its merger with Aduro Biotech, Inc. in 2020 and recorded liabilities for contingent value rights and contingent consideration liabilities. The contingent value rights and contingent consideration liabilities are recorded at fair value at the end of each reporting period, and determined by management using the income approach, primarily using discounted cash flow models. Management applied significant judgment in determining the fair value of the contingent value rights and contingent consideration liabilities, which involved the use of significant estimates and assumptions including estimated revenues

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and costs, the probability of technical and regulatory success and discount rates. The fair value of the contingent value rights and the contingent consideration liabilities as of December 31, 2021 is $34.6 million and $5.2 million, respectively.   

The principal considerations for our determination that performing procedures relating to the valuation of the contingent value rights and contingent consideration liabilities is a critical audit matter are (i) the significant judgment by management when determining the fair value of the contingent value rights and contingent consideration liabilities and (ii) a high degree of auditor judgment, subjectivity, and effort in performing procedures and evaluating management’s significant assumption relating to the probability of technical and regulatory success.        

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included, among others, (i) reading and evaluating the agreements relating to the contingent value rights and contingent consideration liabilities; (ii) testing management’s process for determining the fair value of the contingent value rights and contingent consideration liabilities; (iii) evaluating the appropriateness of the discounted cash flow models; and (iv) evaluating the reasonableness of the significant assumption used by management related to the probability of technical and regulatory success. The probability of technical and regulatory success was evaluated by considering external market and industry data.      

/s/ PricewaterhouseCoopers LLP

Seattle, Washington

March 17, 2022

We have served as the Company’s auditor since 2019.

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Chinook Therapeutics, Inc.

Consolidated Balance Sheets

(in thousands, except per share amounts)