UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934

(Amendment No. )

Filed by the Registrant  ☒

Filed by a Party other than the Registrant  ☐

Check the appropriate box:

Chinook Therapeutics, Inc.

(Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

CHINOOK THERAPEUTICS, INC.

400 Fairview Avenue North, Suite 900

Seattle, WA 98109

(206) 485-7241

July 10, 2023

To Our Stockholders:

You are invited to attend a special meeting of the stockholders of Chinook Therapeutics, Inc., a Delaware corporation (“Chinook,” the “Company,” “we,” “our” or “us”), which will be held as a virtual meeting on August 2, 2023 at 10:00 a.m. Pacific Time. We refer to such meeting, including any adjournment or postponement thereof, as the “Special Meeting.” You will be able to participate in the Special Meeting via live webcast by visiting www.virtualshareholdermeeting.com/KDNY2023SM. You will not be able to attend the Special Meeting physically. For purposes of attendance at the Special Meeting, all references in this proxy statement to “present in person” or “in person” shall mean virtually present at the Special Meeting.

At the Special Meeting, you will be asked to consider and vote on a proposal to adopt the Agreement and Plan of Merger (as it may be amended from time to time, the “Merger Agreement”), dated as of June 11, 2023, by and among Chinook, Novartis AG, a company organized under the laws of Switzerland (“Novartis”), and Cherry Merger Sub Inc., a Delaware corporation and an indirect wholly owned subsidiary of Novartis (“Merger Sub”). Pursuant to the terms of the Merger Agreement, Merger Sub will be merged with and into Chinook (the “Merger”), the separate existence of Merger Sub will cease, and Chinook will continue as the Surviving Corporation. You will also be asked to consider and vote on (1) a proposal to approve, on an advisory (non-binding) basis, certain compensation that may be paid or become payable to our named executive officers in connection with the Merger; and (2) a proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to approve the proposal to adopt the Merger Agreement.

If the Merger Agreement is adopted and the Merger is completed, Chinook will become an indirect wholly owned subsidiary of Novartis, and, at the Effective Time of the Merger, you will be entitled to receive (i) $40.00 per share in cash without interest and less any applicable withholding taxes, and (ii) one contractual contingent value right (a “CVR”) pursuant to the form of CVR Agreement to be entered into at or prior to the Effective Time of the Merger by Novartis and Computershare Trust Company, N.A. as Rights Agent (the “Rights Agent”) (the “CVR Agreement”), for each share of Chinook common stock, par value $0.0001 per share (“our common stock”) that you own at the Effective Time of the Merger (other than with respect to any shares of our common stock as to which you properly demand and perfect appraisal rights in accordance with Section 262 of the General Corporation Law of the State of Delaware).

Our board of directors (our “Board”) has unanimously determined that the Merger Agreement, the CVR Agreement and the transactions contemplated by the Merger Agreement and the CVR Agreement, including the Merger, are fair to, and in the best interests of, Chinook and its stockholders, approved and declared advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, directed that the Merger Agreement be submitted to the Chinook stockholders for adoption at the Special Meeting and recommended that the Chinook stockholders adopt the Merger Agreement. Accordingly, our Board unanimously recommends that the stockholders of Chinook Therapeutics, Inc. vote (1) “FOR” the

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proposal to adopt the Merger Agreement, (2) “FOR” the advisory (non-binding) proposal to approve certain compensation that may be paid or become payable to the named executive officers of Chinook in connection with the Merger, and (3) “FOR” the proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies.

Your vote is very important. The Merger cannot be completed unless holders of a majority of the outstanding shares of our common stock entitled to vote on the Merger Agreement at the Special Meeting or any adjournment or postponement thereof cast their vote in favor of the proposal to adopt the Merger Agreement. A failure to vote your shares of our common stock on the proposal to adopt the Merger Agreement will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement.

The attached proxy statement provides you with detailed information about the Special Meeting, the Merger Agreement (including the form of CVR Agreement, which is an exhibit to the Merger Agreement) and the Merger. A copy of the Merger Agreement is attached as Annex A to the accompanying proxy statement. We encourage you to read the accompanying proxy statement and the Merger Agreement carefully and in their entirety. You may also obtain more information about Chinook from documents we have filed with the Securities and Exchange Commission. See “Where You Can Find Additional Information.”

Whether or not you plan to attend the Special Meeting, please complete, date, sign and return, as promptly as possible, the enclosed proxy card in the accompanying reply envelope, or submit your proxy by telephone or the Internet. If you attend the Special Meeting and vote in person, your vote by ballot will revoke any proxy previously submitted.

If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions.

If you have any questions or need assistance in voting your shares, please contact our proxy solicitor, MacKenzie Partners, Inc., toll free, at (800) 322-2885.

On behalf of our Board, I thank you for your support and appreciate your consideration of this matter.

Sincerely,

Eric Dobmeier Chief Executive Officer

Neither the Securities and Exchange Commission nor any state securities regulatory agency has approved or disapproved the Merger, passed upon the merits or fairness of the Merger, the Merger Agreement or the other transactions contemplated thereby or passed upon the adequacy or accuracy of the disclosure in the accompanying proxy statement. Any representation to the contrary is a criminal offense.

The accompanying proxy statement is dated July 10, 2023 and is first being mailed to stockholders on or about July 10, 2023.

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CHINOOK THERAPEUTICS, INC.

400 Fairview Avenue North, Suite 900

Seattle, WA 98109

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS

TO BE HELD ON AUGUST 2, 2023

NOTICE IS HEREBY GIVEN that a special meeting of the stockholders of Chinook Therapeutics, Inc., a Delaware corporation (which we refer to as “Chinook,” the “Company,” “we,” “our” or “us”), will be held via a virtual meeting on August 2, 2023 at 10:00 a.m. Pacific Time (the “Special Meeting”). You will be able to participate in the Special Meeting via live webcast by visiting www.virtualshareholdermeeting.com/KDNY2023SM. You will not be able to attend the Special Meeting physically. For purposes of attendance at the Special Meeting, all references in this proxy statement to “present in person” or “in person” shall mean virtually present at the Special Meeting. The Special Meeting is being held to consider and vote upon the following proposals:

Only stockholders of record as of the close of business on July 3, 2023 are entitled to notice of and to vote at the Special Meeting and at any adjournment or postponement thereof.

Our Board unanimously recommends that our stockholders vote (1) “FOR” the proposal to adopt the Merger Agreement, (2) “FOR” the advisory (non-binding) proposal to approve certain compensation that may be paid or become payable to the named executive officers of Chinook in connection with the Merger, and (3) “FOR” the proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies.

If the Merger is consummated, holders of shares of our common stock who do not vote in favor of the adoption of the Merger Agreement, who properly demand an appraisal of their shares in accordance with Delaware law, who continuously hold such shares through the Effective Time of the Merger, who otherwise comply with the applicable procedures and requirements of Delaware law (including with respect to certain aggregate ownership requirements) and who do not withdraw their demands, waive or otherwise lose their rights to appraisal will, subject to certain conditions and limitations under Delaware law, be entitled to seek appraisal of the fair value of their shares in connection with the Merger. The relevant section of the General Corporation Law of the State of Delaware regarding appraisal rights, may be accessed without subscription or cost at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262.

Your vote is important, regardless of the number of shares of our common stock you own. Regardless of whether you plan to attend the Special Meeting in person, we request that you complete, sign, date and return the enclosed proxy or submit your proxy by telephone or the Internet prior to the Special Meeting to ensure that your shares will be represented at the Special Meeting. If you have Internet access, we encourage you to submit your proxy via the Internet. If you attend the Special Meeting, you may revoke your proxy and vote in person if you wish,

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even if you have previously returned your proxy card. Before voting your shares, we urge you to read the accompanying proxy statement carefully, including its annexes and the documents incorporated by reference in the document. Your prompt attention is greatly appreciated.

By order of our board of directors,

Eric Dobmeier

Chief Executive Officer

Seattle, Washington

July 10, 2023

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YOUR VOTE IS IMPORTANT

WHETHER OR NOT YOU PLAN TO ATTEND THE SPECIAL MEETING IN PERSON, WE ENCOURAGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE: (1) BY TELEPHONE; (2) THROUGH THE INTERNET; OR (3) BY SIGNING AND DATING THE ENCLOSED PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. You may revoke your proxy or change your vote at any time before it is voted at the Special Meeting.

If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your broker or other agent cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions.

If you are a Chinook stockholder of record, voting in person by virtual ballot at the Special Meeting will revoke any proxy that you previously submitted. If you hold your shares through a bank, broker or other nominee, you must obtain a “legal proxy” in order to vote in person at the Special Meeting.

If you fail to (1) return your proxy card, (2) grant your proxy electronically over the Internet or by telephone, or (3) vote by virtual ballot in person at the Special Meeting, your shares will not be counted for purposes of determining whether a quorum is present at the Special Meeting and, if a quorum is present, will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement, but it will have no effect on the proposal to approve, on an advisory (non-binding) basis, certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger or the proposal to adjourn the Special Meeting.

You should carefully read and consider the entire accompanying proxy statement and its annexes, including, but not limited to, the Merger Agreement (including the form of CVR Agreement, which is an exhibit thereto), along with all of the documents incorporated by reference into the accompanying proxy statement, as they contain important information about, among other things, the Merger and how it affects you. If you have any questions concerning the Merger Agreement, the Merger, the Special Meeting or the accompanying proxy statement, would like additional copies of the accompanying proxy statement or need help voting your shares of Chinook common stock, please contact our proxy solicitor:

MacKenzie Partners, Inc.

1407 Broadway, 27^th Floor

New York, NY 10018

Toll-free: 1-800-322-2885

Email: proxy@mackenziepartners.com

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TABLE OF CONTENTS

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QUESTIONS AND ANSWERS ABOUT THE SPECIAL MEETING AND THE MERGER

The following questions and answers address briefly some questions you may have regarding the Special Meeting and the proposals to be voted on at the Special Meeting. These questions and answers may not address all of the questions that may be important to you as a stockholder of Chinook. Please refer to the more detailed information contained elsewhere in this proxy statement, the annexes to this proxy statement and the documents referred to or incorporated by reference in this proxy statement, which we urge you to read carefully and in their entirety. You may obtain the information incorporated by reference into this proxy statement without charge by following the instructions under the section entitled “Information Incorporated by Reference.”

Q: Why am I receiving this proxy statement?

A: On June 11, 2023, Chinook entered into a definitive agreement providing for the Merger of Merger Sub, an indirect wholly owned subsidiary of Novartis, with and into Chinook, with Chinook surviving the Merger as an indirect wholly owned subsidiary of Novartis. You are receiving this proxy statement in connection with the solicitation of proxies by our Board in favor of the proposal to adopt the Merger Agreement and two related proposals.

Q: What is a proxy?

A: A proxy is your legal designation of another person, referred to as a “proxy,” to vote your shares of our common stock. The written document describing the matters to be considered and voted on at the Special Meeting is called a “proxy statement.” The document used to designate a proxy to vote your shares of our common stock is called a “proxy card.” Our Board has designated Eric Dobmeier, Eric Bjerkholt and Kirk Schumacher, and each of them with full power of substitution, as proxies for the Special Meeting.

Q: When and where is the Special Meeting?

A: We will hold the Special Meeting virtually via the Internet at the virtual meeting website. You will not be able to attend the Special Meeting physically. The Special Meeting will be held on August 2, 2023, at 10:00 a.m. Pacific Time (including any adjournment or postponement thereof, the “Special Meeting”).

Q: Who is entitled to vote at the Special Meeting?

A: Only holders of record of our common stock as of the close of business on July 3, 2023, the Record Date for the Special Meeting, are entitled to receive these proxy materials and to vote their shares at the Special Meeting. As of the close of business on the Record Date, there were 67,049,489 shares of our common stock outstanding and entitled to vote at the Special Meeting, held by approximately 82 holders of record. Each share of our common stock issued and outstanding as of the Record Date will be entitled to one vote on each matter submitted to a vote at the Special Meeting.

Q: What is the difference between holding shares as a stockholder of record and as a beneficial owner?

A: If your shares are registered directly in your name with our transfer agent, Computershare Trust Company, N.A., you are considered, with respect to those shares, to be the “stockholder of record.” In this case, we have sent this proxy statement and your proxy card to you directly.

If your shares are held through a broker, bank or other nominee, you are considered the “beneficial owner” of the shares of our common stock held in “street name.” In that case, this proxy statement has been forwarded to you by your broker, bank or other nominee who is considered, with respect to those shares, to be the stockholder of record. As the beneficial owner, you have the right to direct your broker, bank or other nominee on how to vote your shares by following their instructions for voting. You are also invited to attend the Special Meeting. However, because you are not the stockholder of record, you may not vote your shares in person at the Special Meeting unless you request and obtain a valid legal proxy from your broker, bank or other nominee.

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Q: What matters will be voted on at the Special Meeting?

A: You will be asked to consider and vote on the following proposals:

Q: What is the proposed Merger and what effects will it have on Chinook?

A: The proposed Merger is the acquisition of Chinook by Novartis pursuant to the Merger Agreement. If the proposal to adopt the Merger Agreement is approved by the holders of our common stock and the other closing conditions under the Merger Agreement have been satisfied or waived, Merger Sub will merge with and into Chinook, with Chinook continuing as the Surviving Corporation. As a result of the Merger, Chinook will become an indirect wholly owned subsidiary of Novartis. We will cooperate with Novartis to delist our common stock from the Nasdaq Global Select Market and deregister under the Exchange Act as soon as reasonably practicable following the Effective Time, and once effective, we will no longer be a publicly traded company and will no longer file periodic reports with the SEC. If the Merger is consummated, you will not own any shares of the capital stock of the Surviving Corporation.

Q: What happens if the Merger is not completed?

A: If the Merger Agreement is not adopted by our stockholders or if the Merger is not consummated for any other reason, our stockholders will not receive any payment for their shares of common stock. Instead, we will remain a public company, our common stock will continue to be listed and traded on the Nasdaq Global Select Market and registered under the Exchange Act and we will continue to file periodic reports with the SEC.

Under specified circumstances, upon or following the termination of the Merger Agreement, we may be required to pay Novartis a termination fee or Novartis may be required to pay us a reverse termination fee, as described under “The Merger Agreement—Termination Fees” beginning on page 84.

Q: What will I receive if the Merger is completed?

A: Upon completion of the Merger, you will be entitled to receive the Total Per Share Consideration of (i) $40.00 in cash without interest and less any applicable withholding taxes, and (ii) one CVR for each share of common stock that you own, unless you have properly exercised, perfected and not validly withdrawn, waived or otherwise lost your appraisal rights under the DGCL with respect to such shares, and certain other conditions under the DGCL are satisfied (as described in more detail in the section of this proxy statement entitled “Appraisal Rights”). In either case, you will not own shares in the Surviving Corporation.

Q: What is a CVR and how does it work?

A: While no guarantee can be given that any proceeds will be received, each CVR will represent the right to receive up to $4.00 in contingent cash payments from Novartis upon the achievement by specified dates of certain Milestones set forth in the CVR Agreement, as further described in the section captioned “Contingent Value Rights Agreement,” beginning on page 86 of this proxy statement.

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Q: Is it possible that I will receive more than one payment under the CVR?

A: Yes. Each CVR represents the right to receive:

Q: Is it possible that I will not receive any payment under the CVR?

A: Yes. There can be no assurance that the either of the Milestones will be achieved, and that the resulting payments will be required of Novartis.

Q: Can I transfer my CVR?

A: The CVRs are not transferable except under certain limited circumstances, will not be evidenced by a certificate or other instrument and will not be registered or listed for trading. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Novartis, Merger Sub, Chinook or any of their affiliates.

Q: What will the holders of Chinook stock options, RSUs and PSUs receive in the Merger?

A: Stock Options. As of immediately prior to the Effective Time, each stock option that is outstanding and unexercised will become immediately vested and exercisable in full. At the Effective Time, each stock option that is then-outstanding will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such stock option, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the excess, if any of (A) the Per Share Cash Consideration over (B) the per share exercise price of such stock option, and (ii) one CVR. However, if the per share exercise price of such stock option is equal to or greater than the Per Share Cash Consideration, such stock option will be canceled without any cash payment, CVR or other consideration being made in respect thereof.

Restricted Stock Units. As of immediately prior to the Effective Time, each RSU that is outstanding and not settled will become immediately vested in full. At the Effective Time, each outstanding RSU will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such RSU, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the Per Share Cash Consideration and (ii) one CVR.

Performance Stock Units. As of immediately prior to the Effective Time, each PSU that is outstanding will become immediately vested in full for the maximum number of shares thereunder. At the Effective Time, each outstanding PSU will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such PSU, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the Per Share Cash Consideration, and (ii) one CVR.

Q: What will happen to the Chinook 2015 Employee Stock Purchase Plan in the Merger?

A: No individual who was not a participant in the Chinook 2015 Employee Stock Purchase Plan (the “ESPP”) as of June 11, 2023 may enroll in the ESPP with respect to the offering period under the ESPP in effect as of such date (the “ESPP Offering Period”), and no participant in the ESPP may increase the percentage amount of their payroll deduction election from that in effect as of such date for the ESPP Offering Period. No new offering period or purchase period will commence under the ESPP following June 11, 2023 and, if the purchase date for the ESPP Offering Period would otherwise occur on or after the Effective Time, then the ESPP Offering Period will be shortened and the applicable purchase date with respect to the ESPP Offering Period will occur on the tenth (10^th) business day immediately preceding the date on which the Effective Time occurs.

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Q: When do you expect the Merger to be completed?

A: We are working toward completing the Merger as soon as possible, and currently expect to consummate the Merger during the second half of 2023. However, the exact timing of completion of the Merger cannot be predicted because the Merger is subject to conditions, including adoption of the Merger Agreement by our stockholders and the receipt of certain regulatory approvals, that are out of our control and which may delay the

completion of the Merger or prevent it from being completed at all. See “The Merger Agreement—General” and “The Merger Agreement—Conditions to Completion of the Merger.”

Q: Am I entitled to appraisal or dissenters’ rights under Delaware law?

A: If the Merger is consummated, stockholders who (i) do not vote in favor of the adoption of the Merger Agreement, (ii) continuously hold such shares through the Effective Time, (iii) have properly demanded appraisal of their shares, (iv) meet certain statutory requirements described in this proxy statement and (v) do not validly withdraw their demands or otherwise lose their rights to appraisal of their shares and who meet certain other conditions and ownership requirements described under Section 262 of the DGCL will be entitled to seek appraisal of their shares in connection with the Merger. This means that holders of shares of our common stock may be entitled to have their shares appraised by the Delaware Court of Chancery and to receive payment in cash of the “fair value” of the shares of our common stock, exclusive of any elements of value arising from the accomplishment or expectation of the Merger, together with interest (unless the Delaware Court of Chancery in its discretion determines otherwise for good cause shown) to be paid on the amount determined to be “fair value” from the Effective Time through the date of payment of the judgment, as determined by the Delaware Court of Chancery (subject, in the case of interest payments, to any voluntary cash payments made by Chinook pursuant to subsection (h) of Section 262 of the DGCL, as described in more detail in the section of this proxy statement entitled “Appraisal Rights” beginning on page 96). Stockholders considering seeking appraisal should be aware that the fair value of their shares as determined pursuant to Section 262 of the DGCL could be more than, the same as or less than the value of the consideration that they would receive pursuant to the Merger if they did not seek appraisal of their shares. Stockholders who wish to seek appraisal of their shares of our common stock are in any case encouraged to seek the advice of legal counsel with respect to the exercise of appraisal rights due to the complexity of the appraisal process. The DGCL requirements for exercising appraisal rights are described in further detail in the section of this proxy statement captioned “Appraisal Rights,” which is qualified in its entirety by Section 262, the relevant section of the DGCL regarding appraisal rights, which may be accessed without subscription or cost at the following publicly available website: https://delcode.delaware.gov/title8/c001/sc09/index.html#262.

Q: Will I be subject to U.S. federal income tax upon the exchange of Chinook common stock for the Total Per Share Consideration pursuant to the Merger?

A: If you are a U.S. holder (as defined under “The Merger (Proposal 1)—Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 58), the exchange of our common stock for the Total Per Share Consideration pursuant to the Merger generally will be a taxable transaction for U.S. federal income tax purposes. The timing and character of the gain or loss a U.S. holder will recognize as a result of the Merger is subject to significant uncertainty. Because particular circumstances may differ, we recommend that you consult your own tax advisor to determine the U.S. federal income tax consequences relating to the Merger in light of your own particular circumstances and any consequences arising under the laws of any state, local or non-U.S. tax jurisdiction. A more complete description of the U.S. federal income tax consequences of the Merger is provided under “The Merger (Proposal 1)—Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 58 of this proxy statement.

Q: May I attend the Special Meeting and vote in person?

A: Yes. If you are a Chinook stockholder of record, you may attend the Special Meeting virtually via the Internet at the virtual meeting website on www.virtualshareholdermeeting.com/KDNY2023SM, and complete a virtual

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ballot, whether or not you sign and return your proxy card. If you are a Chinook stockholder of record, you will need your assigned control number to vote shares electronically at the Special Meeting. The control number can be found on the proxy card, voting instruction form or other applicable proxy notices.

Even if you plan to attend the Special Meeting in person, to ensure that your shares will be represented at the Special Meeting, we encourage you to sign, date and return the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card). If you attend the Special Meeting and complete a virtual ballot, your vote will revoke any proxy previously submitted.

If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your broker or other agent cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions. If you hold your shares in “street name,” you may not vote your shares in person at the Special Meeting unless you obtain a “legal proxy” from your bank, broker or other nominee.

Q: How many shares are needed to constitute a quorum?

A: A quorum will be present if holders of a majority of the shares of our common stock outstanding at the close of business on the Record Date are present in person or represented by proxy at the Special Meeting. If a quorum is not present at the Special Meeting, the Special Meeting may be adjourned or postponed from time to time until a quorum is obtained.

If you submit a proxy but fail to provide voting instructions or abstain on any of the proposals listed on the proxy card, your shares will be counted for the purpose of determining whether a quorum is present at the Special Meeting.

If your shares are held in “street name” by your broker, bank or other nominee and you do not instruct the nominee how to vote your shares, your broker, bank or other nominee will not vote on your behalf with respect to any of the proposals, and your shares will not be counted for purposes of determining whether a quorum is present for the transaction of business at the Special Meeting.

Q: What if during the check-in time or during the meeting I have technical difficulties or trouble accessing the virtual meeting website?

A: If you encounter technical difficulties accessing the Special Meeting during the check-in time or during the Special Meeting, a support line will be available on the login page of the virtual meeting website.

Q: What vote of Chinook stockholders is required to adopt the Merger Agreement?

A: The affirmative vote of holders of a majority of the issued and outstanding shares of Chinook common stock entitled to vote on the Merger Agreement at the Special Meeting or any adjournment or postponement thereof is required to adopt the Merger Agreement.

If a quorum is present at the Special Meeting, the failure of any Chinook stockholder of record to: (i) submit a signed proxy card; (ii) grant a proxy over the Internet or by telephone (using the instructions provided in the enclosed proxy card); or (iii) vote in person by virtual ballot at the Special Meeting will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement. If you hold your shares in “street name” and a quorum is present at the Special Meeting, the failure to instruct your bank, broker or other nominee how to vote your shares will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement. If a

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quorum is present at the Special Meeting, abstentions will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement.

Each “broker non-vote” will also count as a vote “AGAINST” the proposal to adopt the Merger Agreement.

Q: What vote of Chinook stockholders is required to approve the other proposals to be voted upon at the Special Meeting?

A: Approval of each of the advisory (non-binding) proposal to approve certain compensation that may be paid or become payable to the named executive officers of Chinook in connection with the Merger and the proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies, requires the affirmative vote of a majority of the shares of our common stock present in person or represented by proxy at the Special Meeting and entitled to vote on such proposal and are voted for or against such proposal.

An abstention with respect to either the advisory (non-binding) proposal to approve certain compensation that may be paid or become payable to the named executive officers of Chinook in connection with the Merger and the proposal to adjourn the Special Meeting will not be considered to be a vote “for” or “against,” and therefore will have no effect on these proposals. A failure to submit a proxy or the failure of your broker, bank or other nominee to vote shares held on your behalf will not have any effect on either of these proposals.

Q: How does our Board recommend that I vote?

A: Our Board unanimously recommends that our stockholders vote:

For a discussion of the factors that our Board considered in determining to recommend the adoption of the Merger Agreement, please see the section entitled “The Merger (Proposal 1)—Reasons for the Recommendation of our Board.” In addition, in considering the company recommendation with respect to the Merger Agreement, you should be aware that some of our directors and executive officers have potential interests that may be different from, or in addition to, the interests of our stockholders generally. For a discussion of these interests, please see the section entitled “The Merger (Proposal 1)—Interests of Chinook’s Directors and Executive Officers in the Merger.”

Q: How do Chinook’s directors and officers intend to vote?

A: We currently expect that our directors and executive officers will vote their shares in favor of the proposal to adopt the Merger Agreement and the other proposals to be considered at the Special Meeting, although they have no obligation to do so.

Q: What will happen if stockholders do not approve the advisory (non-binding) proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger?

A: The inclusion of this proposal is required by the SEC rules; however, the approval of this proposal is not a condition to the completion of the Merger and the vote on this proposal is an advisory vote by stockholders and is

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not binding on Chinook or Novartis. If the Merger Agreement is adopted by Chinook stockholders and the Merger is completed, the Merger-related compensation will be paid to Chinook’s named executive officers in accordance with the terms of their compensation agreements and arrangements even if stockholders do not approve this proposal.

Q: What do I need to do now?

A: You should carefully read and consider this entire proxy statement and the annexes to this proxy statement, including, but not limited to, the Merger Agreement (including the form of CVR Agreement that is an exhibit thereto), along with all of the documents that we refer to in this proxy statement, as they contain important information about, among other things, the Merger and how it affects you. Then sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying reply envelope, or grant your proxy electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card), so that your shares can be voted at the Special Meeting, unless you wish to seek appraisal. If you hold your shares in “street name,” please refer to the voting instruction forms provided by your bank, broker or other nominee to vote your shares.

Q: How do I vote my shares of our common stock?

A: If you are a Chinook stockholder of record (that is, if your shares of Chinook common stock are registered in your name with Computershare Trust Company, N.A., our transfer agent), there are four (4) ways to vote:

A control number, located on your proxy card, is designed to verify your identity and allow you to vote your shares of Chinook common stock, and to confirm that your voting instructions have been properly recorded when voting electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card). Please be aware that, although there is no charge for voting your shares, if you vote electronically over the Internet by visiting the address on your proxy card or by telephone by calling the phone number on your proxy card, in each case, you may incur costs such as Internet access and telephone charges for which you will be responsible.

Even if you plan to attend the Special Meeting in person, you are strongly encouraged to vote your shares of Chinook common stock by proxy. If you are a record holder or if you obtain a “legal proxy” to vote shares that you beneficially own, you may still vote your shares of Chinook common stock in person by virtual ballot at the Special Meeting even if you have previously voted by proxy. If you are present at the Special Meeting and vote in person by virtual ballot, your previous vote by proxy will not be counted.

If your shares are held in “street name” through a bank, broker or other nominee, you may vote through your bank, broker or other nominee by completing and returning the voting form provided by your bank, broker or other nominee, or, if such a service is provided by your bank, broker or other nominee, electronically over the Internet or by telephone. To vote over the Internet or by telephone through your bank, broker or other nominee, you should follow the instructions on the voting form provided by your bank, broker or nominee.

Q: Can I revoke my proxy?

A: Yes. You may revoke your proxy and change your vote at any time before your proxy is voted at the Special Meeting. If you are a stockholder of record, you may revoke your proxy by (i) delivering a later-dated proxy in

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writing, over the telephone or via the Internet, and submitting it so that it is received prior to the cut-off time in accordance with the instructions included in the proxy card; (ii) delivering a written notice of revocation to our Corporate Secretary, Chinook Therapeutics, Inc., 400 Fairview Avenue North, Suite 900, Seattle, WA 98109 that is received prior to the Special Meeting, stating that you revoke your proxy; or (iii) attending the Special Meeting and voting in person. If you hold your shares in “street name” and you have instructed a broker, bank or other nominee to vote your shares, you should instead follow the instructions received from your broker, bank or other nominee to revoke your prior voting instructions.

Q: Will my shares of Chinook common stock held in “street name” or another form of record ownership be combined for voting purposes with shares I hold of record?

A: No. Your bank, broker or other nominee is permitted to vote your shares on any proposal currently scheduled to be considered at the Special Meeting only if you instruct your bank, broker or other nominee how to vote. You should follow the procedures provided by your bank, broker or other nominee to vote your shares. Without instructions, your shares will not be voted on such proposals, which will have the same effect as if you voted “AGAINST” adoption of the Merger Agreement, but it will have no effect on the proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger or the proposal to adjourn the Special Meeting.

Q: What does it mean if I get more than one proxy card or voting instruction card?

A: Please sign, date and return (or grant your proxy electronically over the Internet or by telephone using the instructions provided in the enclosed proxy card) each proxy card and voting instruction card that you receive.

You may receive more than one set of voting materials, including multiple copies of this proxy statement and multiple proxy cards or voting instruction cards. For example, if you hold your shares in more than one brokerage account, you will receive a separate voting instruction card for each brokerage account in which you hold shares. If you are a Chinook stockholder of record and your shares are registered in more than one name, you will receive more than one proxy card.

Q: What happens if I sell my shares of Chinook common stock before completion of the Merger?

A: In order to receive the Total Per Share Consideration, you must hold your shares of our common stock through completion of the Merger. Consequently, if you transfer your shares of our common stock before completion of the Merger, you will have transferred your right to receive the Total Per Share Consideration in the Merger.

The Record Date for stockholders entitled to vote at the Special Meeting is earlier than the consummation of the Merger. If you transfer your shares of our common stock after the Record Date but before the closing of the Merger, you will have the right to vote at the Special Meeting but not the right to receive the Total Per Share Consideration.

Q: Should I send in evidence of ownership now?

A: No. If your shares of our common stock are held in “street name” by your broker, bank or other nominee, you may receive instructions from your broker, bank or other nominee as to what action, if any, you need to take to effect the surrender of your “street name” shares in exchange for the Total Per Share Consideration.

Q: Who will count the votes?

A: The inspector of elections appointed for the Special Meeting will tabulate votes cast by proxy or by ballot at the Special Meeting. The inspector of elections will also determine whether a quorum is present.

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Q: Where can I find the voting results of the Special Meeting?

A: We intend to announce preliminary voting results at the Special Meeting and publish final results in a Current Report on Form 8-K that will be filed with the SEC following the Special Meeting. All reports that we file with the SEC are publicly available when filed. See “Where You Can Find Additional Information” on page 104 of this proxy statement.

Q: Who will solicit and pay the cost of soliciting proxies?

A: The expenses of soliciting proxies will be paid by us. We have retained MacKenzie Partners, Inc. to assist in soliciting proxies for a fee of up to $25,000 plus costs and expenses. We and our agents may solicit proxies by mail, electronic mail, telephone, facsimile, by other similar means or in person. Our directors, officers and other employees, without additional compensation, and employees of MacKenzie may solicit proxies personally or in writing, by telephone, email or otherwise. We will request brokers, custodians, nominees and other record holders to forward copies of the soliciting materials to persons for whom they hold shares and to request authority for the exercise of proxies. In such cases, we, upon the request of the record holders, will reimburse such holders for their reasonable expenses. If you choose to access the proxy materials through the internet, you are responsible for any internet access charges you may incur.

Q: Where can I find more information about Chinook?

A: You can find more information about us from various sources described in the section entitled “Where You Can Find Additional Information.”

Q: What is householding and how does it affect me?

A: The SEC permits companies to send a single set of certain disclosure documents to stockholders who share the same address and have the same last name, unless contrary instructions have been received, but only if the applicable company provides advance notice and follows certain procedures. In such cases, each stockholder continues to receive a separate proxy card. This practice, known as “householding,” is designed to reduce duplicate mailings and save significant printing and postage costs as well as natural resources.

If you received a householded mailing and you would like to have additional copies of this proxy statement mailed to you, or you would like to opt out of this practice for future mailings, please submit your request to Chinook in care of the Corporate Secretary at 400 Fairview Avenue North, Suite 900, Seattle, WA 98109, Attn: Corporate Secretary, or by calling (206) 485-7241. We will promptly send additional copies of this proxy statement upon receipt of such request.

Q: Who can help answer my other questions?

A: If you have more questions about the Merger or require assistance in submitting your proxy or voting your shares or need additional copies of this proxy statement or the enclosed proxy card, please contact MacKenzie Partners, Inc., which is acting as the proxy solicitation agent and information agent for Chinook in connection with the Merger.

If you have questions or need assistance voting your shares please contact:

MacKenzie Partners, Inc.

1407 Broadway, 27^th Floor

New York, NY 10018

Toll-free: 1-800-322-2885

Email: proxy@mackenziepartners.com

If your broker, bank or other nominee holds your shares, you should also call your broker, bank or other nominee for additional information.

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CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS

This proxy statement, and any document to which we refer in this proxy statement, contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), Section 21E of the Exchange Act and the Private Securities Litigation Reform Act of 1995, which are intended to be covered by the safe harbor created by such sections and other applicable laws. Such forward-looking statements include statements relating to our strategy, goals, future focus areas and the value of the proposed transaction to our stockholders. These forward-looking statements are based on Chinook management’s beliefs and assumptions and on information currently available to management. Forward-looking statements include all statements that are not historical facts and may be identified by terms such as “may,” “will,” “should,” “expects,” “plans,” “anticipates,” “could,” “intends,” “target,” “projects,” “contemplates,” “believes,” “estimates,” “predicts,” “potential” or “continue” or similar expressions and the negatives of those terms. In addition, the information set forth under the caption “Certain Chinook Unaudited Prospective Financial Information” consists of forward-looking statements. We have based the forward-looking statements contained in this proxy statement primarily on our current expectations and projections, in light of currently available information, about future events and trends that we believe may affect our business, financial condition, results of operations and prospects. These forward-looking statements involve known and unknown risks, uncertainties, and other factors that may cause actual results, performance or achievements to be materially different from any future results, performance or achievements, expressed or implied by the forward-looking statements, including the uncertainty associated with the potential impacts of global political, macroeconomic, social, health and market conditions, including rising inflation and interest rates, political instability, terrorist activities or military conflicts on our business, financial condition, results of operations and prospects. Additional factors that could cause or contribute to such differences include, but are not limited to, the following:

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Many of these factors are beyond our ability to control or predict. In light of the significant uncertainties inherent in the forward-looking statements contained herein, readers should not place undue reliance on forward-looking statements, which speak only as of the date hereof. We cannot guarantee any future results, levels of activity, performance or achievements. Except as required by applicable law, we undertake no obligation to update forward-looking statements to reflect events or circumstances arising after such date.

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THE COMPANIES

Chinook Therapeutics, Inc.

Chinook Therapeutics, Inc., referred to as “Chinook,” the “Company,” “we,” “our” or “us,” is a Delaware corporation. We were incorporated in California as Oncologic, Inc. in 2000. In 2008, we merged with Triton BioSystems, Inc. and subsequently changed our name to Aduro Biotech, Inc. (“Aduro”) in 2009. In June 2011, we reincorporated as a Delaware corporation. On October 5, 2020 Aduro completed a merger with Chinook Therapeutics U.S., Inc. (“Private Chinook”), pursuant to the terms of a Merger Agreement dated as of June 1, 2020, as 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. Immediately following this Merger, Aduro changed its name to “Chinook Therapeutics, Inc.” and the business conducted by Private Chinook became the primary business conducted by the Company.

Chinook is 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. Chinook’s lead program is atrasentan, a phase 3 endothelin receptor antagonist for the treatment of IgAN and other proteinuric glomerular diseases, including focal segmental glomerosclerosis, or FSGS, and Alport syndrome. We are currently conducting the phase 3 ALIGN trial of atrasentan for IgAN and the phase 2 AFFINITY basket trial for proteinuric glomerular diseases. BION-1301, an anti-APRIL monoclonal antibody, is being evaluated in a phase 1/2 trial for IgA nephropathy. CHK-336, an oral small molecule LDHA inhibitor for the treatment of hyperoxalurias, is in phase 1 development. In addition, Chinook’s research and discovery efforts are focused on building a pipeline of precision medicines for rare, severe chronic kidney diseases with defined genetic and molecular drivers. Chinook is leveraging insights from kidney single cell RNA sequencing and large CKD patient cohorts that have been comprehensively panomically phenotyped, with retained biosamples and prospective clinical follow-up, to discover and develop therapeutic candidates with mechanisms of action targeted against key kidney disease pathways.

Our common stock is currently listed on the Nasdaq Global Select Market under the ticker symbol “KDNY.”

Our principal executive offices are located at 400 Fairview Avenue North, Suite 900, Seattle, WA 98109, and our telephone number is (206) 485-7241. Chinook’s website is www.chinooktx.com. The information contained on, or accessible through, our website is not incorporated into, and does not form a part of, this proxy statement or any other report or document on file with or furnished to the SEC.

Novartis AG

Novartis AG, referred to as “Novartis” or “Buyer,” was incorporated on February 29, 1996 under the laws of Switzerland as a stock corporation (Aktiengesellschaft) with an indefinite duration. On December 20, 1996, the predecessor companies of Buyer, Ciba-Geigy and Sandoz, merged into a new entity, creating the Novartis Group. Buyer is domiciled in and governed by the laws of Switzerland. Its registered office is located at Lichtstrasse 35, CH-4056 Basel, Switzerland, and its telephone number is +41-61-324-1111. The following description of Buyer and its business is qualified in its entirety by reference to Buyer’s Annual Report on Form 20-F for the fiscal year ended December 31, 2022.

The Novartis Group is a multinational group of companies specializing in the research, development, manufacturing and marketing of a broad range of innovative pharmaceuticals and cost-saving generic medicines. Buyer is the Novartis Group’s Swiss holding company and owns, directly or indirectly, all of the Novartis Group’s significant operating companies.

As a leading global medicines company, the Novartis Group uses innovative science and technology to discover and develop breakthrough treatments and find new ways to deliver them to as many people as possible. Its broad

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portfolio includes innovative medicines focused on five core therapeutic areas – cardiovascular, immunology, neuroscience, solid tumor and hematology – as well as other promoted brands (in the therapeutic areas of ophthalmology and respiratory) and established brands and generic and biosimilar medicines. The Novartis Group’s continuing operations comprise corporate activities and two global operating divisions, Innovative Medicines and Sandoz, which are further described below:

In addition, these divisions are supported by the following organizational units: Novartis Institutes for BioMedical Research (NIBR), Global Drug Development (GDD) and Operations.

Buyer’s shares are listed in Switzerland on the SIX Swiss Exchange under the symbol “NOVN,” and its American Depositary Shares, each of which represents one Novartis share and is evidenced by an American Depositary Receipt, are traded on the New York Stock Exchange under the symbol “NVS.”

Cherry Merger Sub Inc.

Cherry Merger Sub Inc., referred to as “Merger Sub,” is a Delaware corporation and an indirect wholly owned subsidiary of Novartis. Merger Sub was formed in June 2023 solely for the purpose of entering into the Merger Agreement and consummating the transactions contemplated by the Merger Agreement, and it currently has no other business or operations. Novartis expects that, immediately prior to the Effective Time, Merger Sub will be a direct, wholly owned subsidiary of Novartis Finance Corporation, a New York corporation and an indirect wholly owned subsidiary of Novartis. Upon completion of the Merger, Merger Sub will cease to exist and Chinook will continue as the Surviving Corporation.

Merger Sub’s principal executive offices are located at One Health Plaza, East Hanover, New Jersey 07936, and its telephone number is (862) 778-8300.

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THE SPECIAL MEETING

We are furnishing this proxy statement to Chinook stockholders as part of the solicitation of proxies by our Board for use at the Special Meeting or any adjournment or postponement thereof. This proxy statement provides Chinook stockholders with information about the Special Meeting and should be read carefully and in its entirety.

Date, Time and Place of the Special Meeting

This proxy statement is being furnished to our stockholders as part of the solicitation of proxies by our Board for use at the Special Meeting to be held at on August 2, 2023 at 10:00 a.m. Pacific Time, or at any adjournment or postponement thereof. We will hold the Special Meeting virtually via the Internet at the virtual meeting website. You will not be able to attend the Special Meeting physically.

Purposes of the Special Meeting

At the Special Meeting, Chinook stockholders will be asked to consider and vote on the following proposals:

Our stockholders must approve the proposal to adopt the Merger Agreement for the Merger to occur. If our stockholders fail to adopt the Merger Agreement, the Merger will not occur. A copy of the Merger Agreement is attached to this proxy statement as Annex A, and the material provisions of the Merger Agreement are described in the section entitled “The Merger Agreement.”

The votes on (i) certain compensation that may be paid or become payable in connection with the Merger and (ii) any proposal to adjourn the Special Meeting are votes separate and apart from the vote to adopt the Merger Agreement. Accordingly, a stockholder may vote to approve the compensation proposal and/or for any proposal to adjourn the Special Meeting and vote not to adopt the Merger Agreement and vice versa. In addition. because the vote on the compensation proposal is advisory in nature only, it will not be binding on either Chinook or Novartis. Accordingly, if the proposal to adopt the Merger Agreement is approved by Chinook stockholders and the Merger is completed, the Merger-related compensation may be paid to Chinook’s named executive officers even if the stockholders fail to approve the proposal related to compensation payable in connection with the Merger.

Chinook does not expect a vote to be taken on any other matters at the Special Meeting or any adjournment or postponement thereof. If any other matters are properly presented at the Special Meeting or any adjournment or postponement thereof for consideration, however, the holders of the proxies will have discretion to vote on these matters in accordance with their best judgment.

This proxy statement and the enclosed proxy card are first being mailed to Chinook stockholders on or about July 10, 2023.

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Record Date and Quorum

The holders of record of our common stock as of the close of business on July 3, 2023, the Record Date for the Special Meeting, are entitled to receive notice of and to vote at the Special Meeting. At the close of business on the Record Date, 67,049,489 shares of our common stock were outstanding.

The presence at the Special Meeting, in person or represented by proxy, of the holders of a majority of the voting power of the shares of our common stock outstanding at the close of business on the Record Date will constitute a quorum. Once a share is represented at the Special Meeting, it will be counted for the purpose of determining a quorum at the Special Meeting. However, if a new Record Date is set for an adjourned Special Meeting, then a new quorum will have to be established. Proxies received but marked as abstentions will be included in the calculation of the number of shares considered to be present at the Special Meeting. Broker non-votes will not count for the purpose of determining whether a quorum is present. A broker non-vote occurs when a broker, bank, trustee or nominee holding shares for a beneficial owner does not vote on a particular proposal because the broker or nominee does not have discretionary authority to vote for that particular proposal and has not received instructions from the beneficial owner as to how to vote its shares.

Required Vote

Each share of our common stock outstanding at the close of business on the Record Date is entitled to one vote on each of the proposals to be considered at the Special Meeting.

Approval of the proposal to adopt the Merger Agreement requires the affirmative vote of holders of a majority of the outstanding shares of our common stock entitled to vote on the Merger Agreement at the Special Meeting or any adjournment or postponement thereof. A failure to vote your shares of our common stock or an abstention from voting will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement.

Assuming a quorum is present, approval of the advisory (non-binding) proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger requires the affirmative vote of a majority of the shares of our common stock present in person or represented by proxy at the Special Meeting and entitled to vote on the proposal and are voted for or against the proposal.

Approval of the proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to approve the proposal to adopt the Merger Agreement, requires the affirmative vote of a majority of the shares of our common stock present in person or represented by proxy at the Special Meeting and entitled to vote on the proposal and are voted for or against the proposal.

If you fail to (1) return your proxy card, (2) grant your proxy electronically over the Internet or by telephone, or (3) vote by virtual ballot in person at the Special Meeting, it will have the same effect as if the stockholder voted “AGAINST” the proposal to adopt the Merger Agreement, but it will have no effect on the proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger or the proposal to adjourn the Special Meeting.

If you abstain from voting, it will have the same effect as if the stockholder voted “AGAINST” the Merger proposal, but will not be considered to be a vote “for” or “against,” and will therefore have no effect on, the proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger or the proposal to adjourn the Special Meeting.

If your shares are held in “street name” by your broker, bank or other nominee and you do not instruct the nominee how to vote your shares, such failure to instruct your nominee will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement, but it will have no effect on the proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger or the proposal to adjourn the Special Meeting.

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Voting by Chinook’s Directors and Executive Officers

At the close of business on the Record Date, our directors (and affiliated entities) and executive officers were entitled to vote approximately 9,196,700 shares of our common stock, which in the aggregate represented approximately 13.71% of the shares of our common stock issued and outstanding on that date. We currently expect that our directors and executive officers will vote their shares in favor of the proposal to adopt the Merger Agreement and the other proposals to be considered at the Special Meeting, although they have no obligation to do so.

Voting; Proxies; Revocation

Voting in Person

If you are a Chinook stockholder of record, you may attend the Special Meeting virtually via the Internet at the virtual meeting website on www.virtualshareholdermeeting.com/KDNY2023SM, and complete a virtual ballot, whether or not you sign and return your proxy card. If you are a Chinook stockholder of record, you will need your assigned control number to vote shares electronically at the Special Meeting. The control number can be found on the proxy card, voting instruction form or other applicable proxy notices.

Even if you plan to attend the Special Meeting in person, to ensure that your shares will be represented at the Special Meeting, we encourage you to sign, date and return the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone (using the instructions provided in the enclosed proxy card). If you attend the Special Meeting and complete a virtual ballot, your vote will revoke any proxy previously submitted.

If you hold your shares in “street name,” you should instruct your bank, broker or other nominee how to vote your shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your broker or other agent cannot vote on any of the proposals, including the proposal to adopt the Merger Agreement, without your instructions. If you hold your shares in “street name,” you may not vote your shares in person at the Special Meeting unless you obtain a “legal proxy” from your bank, broker or other nominee.

Providing Voting Instructions by Proxy

To ensure that your shares of our common stock are voted at the Special Meeting, we recommend that you provide voting instructions promptly by proxy, even if you plan to attend the Special Meeting in person.

Shares of Common Stock Held by Record Holders

If you are a stockholder of record, you may provide voting instructions by proxy using one of the methods described below.

To vote over the Internet, go to the web address www.proxyvote.com and follow the instructions for voting. Have your proxy card available when you access the web page. If you vote over the Internet, please do not mail your proxy card.

To vote by telephone, dial 1-800-690-6903 from any touch-tone telephone and follow the instructions. Have your proxy card available when you call. If you vote by telephone, please do not mail your proxy card.

To vote by mail, mark your proxy card, date and sign it and return it in the postage-prepaid envelope. You should not send documents representing our common stock with the proxy card. If the Merger is completed, the Paying Agent for the Merger will send you a letter of transmittal and related materials and instructions for exchanging your shares of our common stock for the Total Per Share Consideration.

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If you vote by proxy (regardless of whether you vote over the Internet, by telephone or by mail), your votes must be received by 11:59 p.m., Eastern Time, on August 1, 2023 to be counted.

Your proxy card will count as a “vote” if you sign, date and return your proxy card without indicating how you wish to vote with respect to a proposal. In this case, your proxy will be voted “FOR” such proposal.

A failure to vote or an abstention will have the same effect as voting “AGAINST” the proposal to adopt the Merger Agreement. A failure to vote or an abstention will not have the effect of either a vote “FOR” or “AGAINST” the other two proposals.

Shares of Common Stock Held in “Street Name”

If you hold your shares in “street name” through a broker, bank or other nominee, you should follow the directions provided by your broker, bank or other nominee regarding how to instruct your broker, bank or other nominee to vote your shares. Without those instructions, your shares will not be voted on any of the proposals, which will have the same effect as voting “AGAINST” the proposal to adopt the Merger Agreement, but, assuming a quorum is present, will not have the effect of either a vote “FOR” or a vote “AGAINST” on the other two proposals.

Brokers, banks and other nominees that hold shares of our common stock in “street name” for their customers do not have discretionary authority to vote the shares with respect to the proposal to adopt the Merger Agreement, the advisory (non-binding) proposal to approve certain compensation that may be paid or become payable to our named executive officers in connection with the Merger, or the adjournment of the Special Meeting, if necessary or appropriate, including to solicit additional proxies. Accordingly, if brokers, banks or other nominees do not receive specific voting instructions from the beneficial owner of such shares, they may not vote such shares with respect to these proposals. Therefore, unless you attend the Special Meeting in person with a properly executed legal proxy from your broker, bank or other nominee, your failure to provide instructions to your broker, bank or other nominee will result in your shares of our common stock not being present at the meeting and not being voted on any of the proposals, which will have the effect of a vote “AGAINST” with respect to the proposal to adopt the Merger Agreement.

Revocation of Proxies

Any person giving a proxy pursuant to this solicitation has the power to revoke and change it at any time before it is voted. If you are a stockholder of record, you may revoke your proxy by:

Please note that only your last-dated proxy will count. Attending the Special Meeting without taking one of the actions described above will not in itself revoke your proxy.

Please note that if you hold your shares in “street name” and you have instructed a broker, bank or other nominee to vote your shares, you should instead follow the instructions received from your broker, bank or other nominee to revoke your prior voting instructions.

Abstentions

An abstention occurs when a stockholder attends a meeting, either in person or represented by proxy, but abstains from voting. Abstentions will be included in the calculation of the number of shares of our common stock present

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or represented at the Special Meeting for purposes of determining whether a quorum has been achieved. Abstaining from voting will have the same effect as a vote “AGAINST” the proposal to adopt the Merger Agreement. Abstaining from voting will have no effect on either the proposal on certain compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger or the proposal to adjourn the Special Meeting.

Board of Directors’ Recommendation

Our Board, after considering various factors described in the section entitled “The Merger (Proposal 1)—Reasons for the Recommendation of our Board,” has unanimously (i) determined that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are fair to and in the best interests of Chinook and its stockholders; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, in each case on the terms and subject to the conditions set forth in the Merger Agreement; (iii) approved the execution, delivery and performance by Chinook of the Merger Agreement and the consummation of the transactions contemplated thereby, including the Merger; (iv) recommended that the holders of Chinook common stock adopt the Merger Agreement; and (v) directed that the Merger Agreement be submitted to Chinook’s stockholders at the Special Meeting of stockholders of Chinook.

Our Board unanimously recommends that you vote (1) “FOR” the proposal to adopt the Merger Agreement, (2) “FOR” the advisory (non-binding) proposal to approve certain compensation that may be paid or become payable to the named executive officers of Chinook in connection with the Merger, and (3) “FOR” the proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies.

List of Stockholders

A list of stockholders entitled to vote at the Special Meeting will be available for examination by any stockholder for any purpose germane to the Special Meeting for ten days prior to the Special Meeting, by contacting our Corporate Secretary at our offices at 400 Fairview Avenue North, Suite 900, Seattle, WA 98109.

Solicitation of Proxies

Our Board is soliciting your proxy, and we will bear the cost of this solicitation of proxies. This includes the charges and expenses of brokerage firms and others for forwarding solicitation material to beneficial owners of our outstanding common stock. We have retained MacKenzie Partners, Inc. (“MacKenzie”), a proxy solicitation firm, to assist our Board in the solicitation of proxies for the Special Meeting, and we expect to pay MacKenzie $25,000 plus reimbursement of out-of-pocket expenses. We have also agreed to indemnify MacKenzie against losses arising out of its provision of these services on our behalf. Directors, officers and employees of ours may also solicit proxies by telephone, by email, by mail, on the Internet or in person. They will not be paid any additional amounts for soliciting proxies.

Other Business

We are not currently aware of any business to be acted upon at the Special Meeting other than the matters discussed in this proxy statement. Under our bylaws, business transacted at the Special Meeting is limited to matters relating to the purposes stated in the notice of the Special Meeting, which is provided at the beginning of this proxy statement. The grant of a proxy will confer discretionary authority on the persons named as proxies on the proxy card to vote in accordance with their best judgment on procedural matters incident to the conduct of the Special Meeting.

Notice Regarding the Availability of Proxy Materials for the Special Meeting to be Held on August 2, 2023

The proxy statement is available at www.proxyvote.com.

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THE MERGER (PROPOSAL 1)

The description of the Merger in this section and elsewhere in this proxy statement is qualified in its entirety by reference to the complete text of the Merger Agreement, a copy of which is attached as Annex A and is incorporated by reference into this proxy statement. This summary does not purport to be complete and may not contain all of the information about the Merger that is important to you. You are encouraged to read the Merger Agreement carefully and in its entirety.

Certain Effects of the Merger

If the proposal to adopt the Merger Agreement is approved by our stockholders and the other conditions to the closing of the Merger are either satisfied or waived, Merger Sub will be merged with and into Chinook, and the separate corporate existence of Merger Sub will cease. Chinook will be the Surviving Corporation in the Merger and will continue its corporate existence as a Delaware corporation and an indirect wholly owned subsidiary of Novartis.

Upon the terms and subject to the conditions of the Merger Agreement, at the Effective Time, each share of our common stock issued and outstanding immediately prior to the Effective Time (other than Excluded Shares and Appraisal Shares) will be converted into the right to receive (i) $40.00 in cash and (ii) one CVR, in each case without interest, less any applicable withholding taxes. At the Effective Time, our current stockholders will cease to have ownership interests in Chinook or rights as its stockholders. Therefore, our current stockholders will not participate in any of our future earnings or growth and will not benefit from any appreciation in our value, other than the if the contingent Milestone Payments are paid pursuant to the CVR.

Immediately prior to the Effective Time, each stock option that is outstanding and unexercised will become immediately vested and exercisable in full. At the Effective Time, each stock option that is then-outstanding will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such option, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the excess, if any, of (A) the Per Share Cash Consideration over (B) the per share exercise price of such stock option and (ii) one CVR. However, if the per share exercise price of such stock option is equal to or greater than the Per Share Cash Consideration, such stock option will be canceled without any cash payment, CVR, or other consideration made in respect thereof. In addition, immediately prior to the Effective Time, each RSU that is outstanding will become immediately vested in full. At the Effective Time, each outstanding RSU will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such RSU, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the Per Share Cash Consideration and (ii) one CVR. Furthermore, immediately prior to the Effective Time, each PSU that is outstanding will become immediately vested in full for the maximum number of shares thereunder. At the Effective Time, each outstanding PSU will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such PSU, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the Per Share Cash Consideration and (ii) one CVR.

Our common stock is currently registered under the Exchange Act and is quoted on the Nasdaq Global Select Market under the symbol “KDNY.” As a result of the Merger, Chinook will cease to be a publicly traded company and will be an indirect wholly owned subsidiary of Novartis. Following the consummation of the Merger, our common stock will be delisted from the Nasdaq Global Select Market and deregistered under the Exchange Act, and Chinook will no longer be required to file periodic reports with the SEC with respect to our common stock, in each case in accordance with applicable law, rules and regulations.

Effects on Chinook if the Merger is Not Completed

If the proposal to adopt the Merger Agreement is not approved by our stockholders or if the Merger is not consummated for any other reason, our stockholders will not receive any payment for their shares of common

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stock. Instead, we will remain a public company, our common stock will continue to be listed and traded on the Nasdaq Global Select Market and registered under the Exchange Act and we will continue to file periodic reports with the SEC. In addition, if the Merger is not completed, we expect that management will operate the business in a manner similar to that in which it is being operated today and that our stockholders will continue to be subject to the same risks and opportunities as they currently are, including, among other things, general industry, economic and market conditions. Accordingly, if the Merger is not consummated, there can be no assurance as to the effect of these risks and opportunities on the future value of your shares of our common stock. From time to time, our Board will evaluate and review our business operations, properties, dividend policy and capitalization, among other things, make such changes as are deemed appropriate and continue to seek to identify strategic alternatives to maximize stockholder value. If the proposal to adopt the Merger Agreement is not approved by our stockholders or if the Merger is not consummated for any other reason, there can be no assurance that any other transaction acceptable to us will be offered or that our business, prospects or results of operations will not be adversely impacted.

If the Merger Agreement is terminated, under specified circumstances, we may be required to pay Novartis a termination fee, or Novartis may be required to pay us a reverse termination fee, as described under “The Merger Agreement—Termination Fees.”

Background of the Merger

The Board and management of Chinook have regularly reviewed long-term strategies and opportunities to enhance stockholder value, including partnering and collaboration opportunities. In this regard, members of management have engaged in discussions regarding Chinook’s programs and/or potential strategic transactions as part of ordinary course business development activities, focused on Chinook’s atrasentan product candidate. On November 3, 2022, Chinook announced interim data from its phase 2 clinical trial for its lead compound, atrasentan for IgA nephropathy (“IgAN”), and indicated that it expected to report topline data from our phase 3 ALIGN trial in 2023, which data may potentially support an application for accelerated FDA approval for this indication. In light of the substantial resources that would be required to commercialize atrasentan, Chinook determined to evaluate collaboration opportunities for atrasentan outside the United States. In 2022 and early 2023, representatives of Chinook met with representatives of a number of pharmaceutical companies and discussed potential collaborations for atrasentan, including with Novartis on November 5, 2022, January 10, 2023 and March 22, 2023. However, during this period, no proposal for a potential acquisition of Chinook was made by any party, including Novartis.

On May 4, 2023, Vasant Narasimhan, the chief executive officer of Novartis, spoke with Eric Dobmeier, our chief executive officer, and orally proposed an acquisition of Chinook by Novartis at an all-cash purchase price of $32.00 per share of Chinook common stock. Later that same day, Novartis sent Chinook a written non-binding preliminary proposal for an acquisition of Chinook at an all-cash purchase price of $32.00 per share of Chinook common stock, indicating that this price represented a 67% premium to our closing price on May 3, 2023 (the “May 4 Proposal”). The May 4 Proposal indicated, among other things, that it was not subject to any financing condition, and that Novartis was prepared to move forward expeditiously and expected that its due diligence and the negotiation of the transaction agreements could be completed within a matter of three to four weeks from the date of engagement.

Following receipt of the May 4 Proposal, Mr. Dobmeier contacted the members of our Board to inform them of the May 4 Proposal, and scheduled a meeting of our Board for the following day. On May 5, 2023, our Board met, together with members of our senior management and representatives of Fenwick & West LLP (“Fenwick & West”), our outside legal advisor. Representatives of Fenwick & West reviewed the fiduciary duties of the Board under Delaware law in considering an acquisition proposal. At the meeting, our Board discussed with our management the opportunities and risks facing us as an independent company. Our Board also discussed the engagement of financial advisors to assist it in evaluating the May 4 Proposal and potentially negotiating the proposal, as well as contacting other parties with the potential strategic interest and financial ability to make a

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competing proposal. Our Board determined to have each of Centerview Partners LLC (“Centerview”) and MTS Health Partners, L.P. (“MTS”), which firms had previously discussed strategic matters from time to time with our senior management, meet with the Board on the following day to assist the Board in further considering the May 4 Proposal.

On May 6, 2023, our Board met, together with members of our senior management and representatives of Centerview, MTS and Fenwick & West, and further discussed the May 4 Proposal, the current environment for strategic transactions in our industry and the opportunities and risks that we faced as an independent company. In addition, our Board discussed with Chinook management and representatives of Centerview and MTS other companies that would be likely to have a strategic interest in, and financial ability to complete, an acquisition of Chinook, and the response to be made to Novartis. Following discussion, our Board directed Mr. Dobmeier to inform Novartis that its offer was not sufficient to move forward into comprehensive due diligence, but that we would be willing to make a management presentation regarding our clinical and preclinical programs and market opportunities in order to enable Novartis to determine whether it would be willing to increase its proposed offer price. In addition, our Board directed representatives of Centerview to contact representatives of five other pharmaceutical companies, referred to as Company A, Company B, Company C, Company D and Company E, to ascertain whether they would be interested in making a proposal to acquire Chinook. These five companies were selected by our Board based on its belief, following the discussion at this meeting, that these were the companies most likely to be both interested in an acquisition of Chinook and have the financial ability to complete such a transaction. These five companies were also among those with which Chinook had previously discussed collaborations for atrasentan. Following this discussion, the representatives of Centerview and MTS left the meeting. The Board then discussed the retention of financial advisors to assist in a potential sale process, and authorized Chinook’s management to engage Centerview and MTS to act in this capacity based on their knowledge of the pharmaceutical industry, their experience in advising on transactions involving companies similar to Chinook, their reputations and their familiarity with Chinook and its business.

On May 8, 2023, Mr. Dobmeier spoke with Mr. Narasimhan and, as directed by our Board, indicated that Chinook would be willing to make a management presentation to Novartis regarding our clinical and preclinical programs and market opportunities in order to assist Novartis in evaluating whether to submit a revised proposal reflecting an increase in the purchase price per share.

From May 8, 2023 through May 10, 2023, representatives of Centerview contacted each of the five parties, as directed by the Board. In initial discussions with representatives of Centerview regarding the opportunity, Company A indicated it was not interested in evaluating an acquisition of Chinook, while each of Company B, Company C and Company D stated that such company would review the opportunity internally and inform Centerview if it had an interest in evaluating an acquisition of Chinook.

On May 9, 2023, Novartis provided Chinook with a list of priority due diligence requests that it indicated would be relevant to its valuation of Chinook and Centerview provided Novartis with a form of confidentiality agreement prepared by Fenwick & West.

On May 11, 2023, each of Company B and Company C indicated it was not interested in evaluating the opportunity further. Company E indicated that it was interested in receiving a presentation from our management and obtaining additional information. Accordingly, on May 11, 2023, Centerview provided Company E with the same form of confidentiality agreement as it had provided to Novartis.

On May 12, 2023, Novartis entered into a confidentiality agreement with Chinook. This confidentiality agreement included a customary standstill restriction that would expire upon the occurrence of specified events, including Chinook’s entry into an agreement providing for an acquisition of Chinook or the commencement of a tender offer for Chinook common stock that our Board does not reject within 10 business days. This confidentiality agreement did not include a provision prohibiting Novartis from making any request that Chinook waive the standstill restriction, known as a “don’t ask/don’t waive” provision. Following execution of this

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confidentiality agreement, Chinook provided Novartis with online access to limited due diligence information regarding our clinical and preclinical programs and market opportunities, the status of our clinical trials and information from our trials that was available to us, including safety data with respect to atrasentan.

On May 15, 2023, members of our senior management, including Mr. Dobmeier, Eric Bjerkholt (our chief financial officer), Andrew King (our chief scientific officer), Tom Frohlich (our chief operating officer), Andrew Oxtoby (our chief commercial officer) and Kirk Schumacher (our general counsel), along with representatives of Centerview, had an online meeting with representatives of Novartis, and made a presentation regarding our clinical and preclinical programs and market opportunities, the status of our clinical trials and information from our trials that was available to us, including safety data with respect to atrasentan.

On May 16, 2023, Company E provided comments on the form of confidentiality agreement that had been provided to it, which we then negotiated with Company E through May 23, 2023.

On May 16, 2023, our Board met, together with members of our senior management and representatives of Fenwick & West and, for part of the meeting, representatives of Centerview and MTS. During the course of this meeting, representatives of Centerview and MTS reviewed the discussions that had taken place with Novartis and each of Company A, Company B, Company C, Company D and Company E.

On May 22, 2023, a representative of Novartis spoke with a representative of Centerview and indicated that Novartis would increase its proposed all-cash purchase price to $36.00 per share of Chinook common stock (the “May 22 Proposal”).

Later on May 22, 2023, our Board met, together with members of our senior management and representatives of Centerview, MTS and Fenwick & West, and discussed the May 22 Proposal. In addition, at this meeting, our Board reviewed a proposed long-range financial forecast of our operating results through 2043 prepared by our management (the “Long-Range Forecast”). The Board discussed the Long-Range Forecast and approved the use of the Long-Range Forecast by Centerview in its financial analysis. Additional information regarding the Long-Range Forecast is set forth in the section entitled “ —Certain Chinook Unaudited Prospective Financial Information.” Representatives of Centerview then discussed a preliminary analysis of the May 22 Proposal from a financial point of view based on the Long-Range Forecast, and discussed the status of outreach to each of Company A, Company B, Company C, Company D and Company E and their respective responses, including that each of Company A, Company B and Company C had indicated that such company would not be interested in discussing a potential acquisition of Chinook, that Company D had not communicated further following the May 10 outreach by Centerview, and that Company E had expressed interest in receiving information regarding Chinook in order to further consider whether it would be interested in further discussions. Our Board then discussed an appropriate response to the May 22 Proposal, including whether to request that Novartis submit a further enhanced proposal without providing guidance as to a price that would be acceptable to our Board or to provide Novartis with a specific price that our Board believed, following consultation with Centerview, would be the highest price Novartis would likely be willing to pay. Following this discussion, our Board directed the representatives of Centerview to respond to Novartis that Chinook would be willing to proceed at a price of $40.00 per share of Chinook common stock in cash and a contingent value right that would pay $4.00 per share of Chinook common stock upon submission to the FDA of a New Drug Application (“NDA”) for atrasentan for IgAN.

On May 23, 2023, a representative of Centerview spoke with a representative of Novartis and communicated this proposal.

Also on May 23, 2023, Chinook entered into a confidentiality agreement with Company E. This confidentiality agreement included a customary standstill restriction that would expire upon the occurrence of specified events that were similar to those included in the confidentiality agreement with Novartis, and which, similar to the Novartis confidentiality agreement, did not include a “don’t ask/don’t waive” provision.

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Following execution of the confidentiality agreement with Company E, on May 24, 2023, members of our senior management, including Mr. Dobmeier, Mr. Bjerkholt, Dr. King, Mr. Frohlich, Mr. Oxtoby and Mr. Schumacher, had an online meeting with representatives of Company E and provided an overview of our business, our product candidates and their market opportunities, the status of our clinical trials and information from our trials that was available to us, including safety data with respect to atrasentan. On May 25, 2023, Chinook provided Company E with online access to due diligence information that was similar to the information that had previously been provided to Novartis.

On May 26, 2023, a representative of Novartis spoke with a representative of Centerview and informed him that Novartis would be willing to increase the proposed purchase price to $40.00 per share of Chinook common stock in cash and a contingent value right that would pay $4.00 per share of Chinook common stock upon FDA approval of atrasentan for focal segmental glomerulosclerosis (the “May 26 Proposal”). As part of the May 26 Proposal, the representative of Novartis also requested that Chinook negotiate with Novartis on an exclusive basis.

Later on May 26, 2023, our Board met, together with representatives of Centerview, MTS and Fenwick & West, and discussed the May 26 Proposal, the previously reported results of the outreach to each of Company A, Company B, Company C, Company D and Company E, and the fact that Company E had not communicated with Chinook management or representatives of Centerview after the May 24 presentation. The Board discussed the proposed consideration of $40.00 per share of Chinook common stock at the closing of the proposed merger, and the proposed payment milestone of the $4.00 per share of Chinook common stock pursuant to the contingent value right, including a discussion of the anticipated timeline for clinical trials of, and submission of an NDA for atrasentan for focal segmental glomerulosclerosis (“FSGS”), and the risks involved with respect to those clinical trials and FDA approval. The Board and representatives of Fenwick & West then discussed certain terms to be set forth in a draft Merger Agreement to be provided to Novartis once agreement had been reached on the purchase price to be paid by Novartis. In addition, as part of the Board’s discussion of the May 26 Proposal, the Board also discussed the request by Novartis to negotiate on an exclusive basis. Following discussion, our Board determined to respond to Novartis that Chinook would be willing to proceed on an exclusive basis until June 12, 2023 with the possibility of extending such exclusivity to June 20, 2023, at a price of $40.00 per share of Chinook common stock at the closing of the transaction and, in order to increase the probability of a payment pursuant to the CVR, a CVR that would pay $2.00 per share of Chinook common stock upon FDA approval of an NDA for atrasentan for IgAN and $2.00 per share of Chinook common stock upon FDA approval of an NDA for atrasentan for FSGS, and authorized and directed the representatives of Centerview to communicate this proposal to Novartis, as well as our willingness to proceed on an exclusive basis if this proposal was acceptable.

On May 26, 2023, a representative of Centerview spoke with a representative of Novartis and communicated this proposal.

On May 26 and May 27, 2023, our Board confirmed by email its approval of the fees proposed to be payable to Centerview and MTS to serve as our financial advisors. On May 26, 2023, we entered into an engagement letter with Centerview, and on May 28, 2023, we entered into an engagement letter with MTS, to act as our financial advisors in connection with a sale of Chinook.

On May 27, 2023, a representative of Company E indicated to Centerview that it was unlikely to submit an acquisition proposal in the near-term, and in a subsequent conversation, Company E confirmed that it would not be proceeding in its evaluation of an acquisition of Chinook.

Later on May 27, 2023, a representative of Novartis spoke with a representative of Centerview and indicated that Novartis would proceed on the basis of Chinook’s proposal, with the $2.00 payment per share of Chinook common stock being payable on FDA approval of an NDA for atrasentan for IgAN by 2026 with no risk evaluation and mitigation strategy (“REMS”) relating to liver toxicity and another $2.00 per share of Chinook common stock being payable on FDA approval of an NDA for atrasentan for FSGS by the end of 2028. The

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representative of Novartis indicated that this proposal was their best and final offer. Mr. Dobmeier informed our Board of this revised proposal, and our Board directed Chinook to proceed with negotiations with Novartis on the basis of this proposal. The representative of Centerview informed a representative of Novartis of this determination, and subsequently on May 27, 2023, Chinook provided Novartis with access to an expanded virtual data room containing customary due diligence materials. In addition, a representative of Centerview, on behalf of Chinook, confirmed that Chinook would proceed exclusively with Novartis until June 12, 2023, including, following further discussion with Novartis, with the possibility of extending such exclusivity to June 20, 2023.

Also on May 27, 2023, Fenwick & West provided Novartis and Hogan Lovells US LLP, Novartis’s legal counsel (“Hogan Lovells”), with a draft Merger Agreement and a draft CVR Agreement. The draft Merger Agreement provided for, among other things: (i) a transaction to be structured as a cash tender offer followed immediately by a merger; (ii) Novartis to pay us a reverse termination fee equal to 7.0% of the transaction value in the event that the transaction was not consummated due to the failure to obtain required regulatory approvals; and (iii) Chinook to be allowed (a) to provide due diligence information to, and negotiate a merger agreement with, a party making an unsolicited acquisition proposal that constitutes or could reasonably be expected to lead to a superior proposal; and (b) to accept a superior proposal after providing Novartis a right to match such proposal and paying a termination fee equal to 2.5% of the equity value of the transaction price. The draft CVR Agreement provided for two milestone payments of $2.00 each; one would be achieved upon the FDA’s approval of an NDA for atrasentan for the treatment of IgAN without a REMS related to liver toxicity by December 31, 2026, and the second would be achieved upon the FDA’s approval of an NDA for atrasentan for the treatment of FSGS by December 31, 2028. The draft CVR Agreement would also require Novartis to use commercially reasonable efforts to achieve the milestones by the applicable end dates.

Between May 30, 2023 and June 10, 2023, members of our senior management held a number of meetings with representatives of Novartis and discussed Chinook’s business, including its clinical trials; its intellectual property; its early-stage preclinical pipeline; and regulatory; finance; chemistry, manufacturing and controls (“CMC”); tax; human resources; legal and other matters.

On May 31, 2023, we received a letter from Centerview disclosing its relationships with Novartis and its affiliates, which indicated that since January 1, 2020, Centerview has not been engaged on a fee-paying basis to provide financial advisory services to Novartis.

On June 3, 2023, Fenwick & West provided Hogan Lovells with a draft of Chinook’s disclosure schedules relating to the draft Merger Agreement.

On June 4, 2023, Hogan Lovells provided Fenwick & West with a revised draft of the Merger Agreement. This revised draft proposed a number of changes to the draft previously circulated by Fenwick & West, including: (i) structuring the transaction as a single-step merger of Chinook with an indirect subsidiary of Novartis; and (ii) accepting the “fiduciary out” provision, but revised the related termination fee from 2.5% to 4% of equity value. A representative of Hogan Lovells also informed a representative of Fenwick & West that the provisions relating to regulatory matters, including the reverse termination fee, would be subsequently addressed.

On June 5, 2023, Fenwick & West provided Hogan Lovells with a further revised draft of the Merger Agreement that, among other things, reduced the amount of the termination fee payable by Chinook if it terminated the Merger Agreement to accept a superior proposal and increased the reverse termination fee payable by Novartis.

Also on June 5, 2023, Hogan Lovells provided Fenwick & West with a revised draft of the CVR Agreement. This revised draft of the CVR Agreement provided, among other things, that the milestone relating to the FDA’s approval of an NDA for atrasentan for the treatment of IgAN must be achieved by March 31, 2025, and that the second milestone would be achieved upon the FDA’s approval of atrasentan for the treatment of FSGS by December 31, 2029, one year later than proposed by the initial draft CVR Agreement. The draft CVR Agreement also stipulated that Novartis would not be required to use any level of efforts or resources to achieve the milestones by the applicable dates.

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On June 6, 2023, representatives of Fenwick & West, Hogan Lovells and Linklaters LLP, antitrust counsel to Novartis (“Linklaters”), met and discussed certain terms of the Merger Agreement related to antitrust matters and the terms of the CVR. During this meeting, Hogan Lovells proposed, among other things, that Novartis would pay a reverse termination fee equal to 5.0% of the transaction value in the event that the Merger could not be completed due to failure to obtain required regulatory clearance. In addition, representatives of Hogan Lovells indicated that Novartis would agree that the milestone related to the FDA’s approval of an NDA for atrasentan for the treatment of IgAN would be satisfied if the FDA’s approval of this NDA occurred by December 31, 2025, rather than the March 31, 2025 date previously proposed. Representatives of Hogan Lovells also reiterated the position that Novartis would not agree to a covenant to use commercially reasonable efforts to achieve either of the milestones set forth in the CVR Agreement.

Subsequently on June 6, 2023, Fenwick & West provided a revised draft of the CVR Agreement to Hogan Lovells, which provided that the first milestone would be achieved upon the FDA’s approval of an NDA for atrasentan for the treatment of IgAN by December 31, 2026 and required Novartis to use commercially reasonable efforts to achieve each milestone.

From June 6, 2023 through June 10, 2023, Fenwick & West and Hogan Lovells continued to negotiate the terms of the Merger Agreement and exchange revised drafts of the Merger Agreement and the CVR Agreement.

On June 7, 2023, Mr. Dobmeier provided our Board with an update on the status of the discussions with Novartis, and informed our Board of the proposal by Novartis that the deadline for the milestone under the CVR Agreement relating to the FDA’s approval of an NDA for atrasentan for the treatment of IgAN be December 31, 2025. The members of our Board indicated that they supported proceeding on that basis. A representative of Fenwick & West subsequently communicated the acceptance of this position to a representative of Hogan Lovells.

On June 8, 2023, Fenwick & West provided Hogan Lovells with an analysis of the effect of Section 280G of the Internal Revenue Code on our executive officers as a result of the Merger, and proposed that Novartis allow us to reimburse those executive officers for the additional excise taxes payable by them as a result of the Merger.

On June 10, 2023, the parties agreed on, among other things, a termination fee of $112.0 million (approximately 3.5% of the equity value of the transaction), a reverse termination fee equal to $192.0 million (approximately 6.0% of the transaction value) in the event that the Merger could not be completed due to failure to obtain required regulatory clearances, and the inclusion of certain other provisions requested by Chinook. In addition, the parties agreed that the CVR Agreement would not include an obligation on the part of Novartis to use commercially reasonable efforts to achieve the milestones.

In addition, on June 10, 2023, representatives of Hogan Lovells informed representatives of Fenwick & West that Novartis would agree to allow us to reimburse those of our executive officers subject to excise taxes under Section 280G of the Internal Revenue Code as a result of the Merger, subject to an aggregate cap on such amounts of $11.6 million.

On June 11, 2023, our Board held a meeting with members of our senior management and representatives of Centerview, MTS and Fenwick & West present. Representatives of Fenwick & West reviewed with the Board the negotiated terms of the Merger Agreement and the CVR Agreement, the form of each of which had been previously distributed to the members of the Board, including the resolution of open issues regarding the size of the respective termination fees, and discussed the fiduciary duties of the Board under Delaware law in evaluating the proposed transaction and the material terms of the Merger Agreement. The Board then discussed the fact that, after outreach to several third parties that the Board, in consultation with its financial advisors, had determined to be the most likely to have the strategic interest and financial ability to pursue an acquisition transaction with Chinook, no other party had expressed an interest in a potential acquisition of Chinook. Representatives of Centerview reviewed with the Board Centerview’s financial analysis of the Total Per Share Consideration, and rendered to the Board an oral opinion, which was subsequently confirmed by delivery of a written opinion dated

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June 11, 2023, that, as of such date and based upon and subject to various assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken in preparing its opinion, the Total Per Share Consideration to be paid to the holders of Chinook common stock (other than as specified in such opinion) pursuant to the Merger Agreement was fair, from a financial point of view, to such holders, as more fully described in the section entitled “—Opinion of Centerview Partners LLC.” The written opinion rendered by Centerview to the Board is attached to this proxy statement as Annex C. Following additional discussion and consideration of the Merger Agreement and the Merger and the other transactions contemplated by the Merger Agreement and the CVR Agreement, the Board unanimously: (i) determined that the Merger Agreement, the CVR Agreement and the transactions contemplated by the Merger Agreement and the CVR Agreement, including the Merger, are fair to and in the best interests of Chinook and its stockholders; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger; (iii) directed that the Merger Agreement be submitted to the Chinook stockholders for adoption at a special meeting; and (iv) recommended that the Chinook Stockholders adopt the Merger Agreement.

Later on June 11, 2023, the parties finalized the Merger Agreement and the CVR Agreement, and thereafter Chinook, Novartis and Merger Sub executed the Merger Agreement. On June 12, 2023, each of Chinook and Novartis issued a press release announcing the execution of the Merger Agreement.

Reasons for the Recommendation of our Board

In recommending that Chinook’s stockholders vote to adopt the Merger Agreement, the Board considered the terms of the Merger, the Merger Agreement and the other transactions contemplated thereby, consulted with Chinook’s senior management and its financial and legal advisors, and considered a number of factors, including the following (which are not necessarily presented in order of relative importance):

Financial Terms; Certainty of Value

The Total Per Share Consideration to be paid by Novartis would provide Chinook’s stockholders with the opportunity to receive a significant premium over recent trading prices of shares of Chinook common stock. The Board considered:

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Prospects of Chinook

The Board considered Chinook’s current and historical business, financial condition, results of operations, competitive position, strategic alternatives and financial prospects, as well as Chinook’s long-term business plan and prospects if it were to remain an independent public company, including:

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Strategic Alternatives

The Board considered the other strategic alternatives available to Chinook, including:

Speed and Likelihood of Consummation

The Board considered the likelihood that the Merger would be consummated in a timely manner, including the following:

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Merger Agreement Terms

The Board considered the terms in the Merger Agreement, including:

General Matters

The Board considered a number of other factors related to the Merger, including:

The Board also considered a number of uncertainties, risks and potentially negative factors in its deliberations concerning the Merger and the other transactions contemplated by the Merger Agreement and the CVR Agreement, including the following (not necessarily in order of relative importance):

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During its consideration of the Merger Agreement, the Merger and the other transactions, the Board also was aware of the fact that some of Chinook’s directors and executive officers have interests in the Merger that differ from or are additive to their interests as those of Chinook’s stockholders generally, which interests are described in the section titled “The Merger (Proposal 1)—Interests of Chinook’s Directors and Executive Officers in the Merger.”

The foregoing discussion is not meant to be exhaustive, but summarizes the material factors considered by the Board in its consideration of the Merger Agreement, the Merger and the other transactions. After considering these and other factors, the Board concluded that the potential benefits of the Merger Agreement, the Merger and the other transactions outweighed the uncertainties and risks. In view of the variety of factors considered by the

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Board and the complexity of these factors, the Board did not find it practicable to, and did not, quantify or otherwise assign relative weights to the foregoing factors in reaching its determination and recommendations. Moreover, each member of the Board applied his or her own personal business judgment to the process and may have assigned different weights to different factors. The Board unanimously approved the Merger Agreement, the Merger and the other transactions, and recommended that Chinook’s stockholders vote in favor of the adoption of the Merger Agreement.

This explanation of our Board’s reasons for recommending the adoption of the Merger Agreement and other information presented in this section is forward-looking in nature and, therefore, should be read in light of the factors described in the section of this proxy statement entitled “Cautionary Statement Concerning Forward-Looking Statements.”

Certain Chinook Unaudited Prospective Financial Information

Chinook does not, as a matter of course, publicly disclose long-term projections or internal projections of its future financial performance, revenues, earnings, financial condition or other results given, among other reasons, the uncertainty of the underlying assumptions and estimates. However, in connection with our Board’s evaluation of the Merger, certain non-public unaudited prospective financial information, including certain analyses and risk-adjusted financial forecasts and projections relating to Chinook on a standalone basis for fiscal years 2023 through 2043 (the “Projections”), were prepared by our management and provided to our Board. The Projections were also provided to Centerview, and Centerview was directed by the Board to use and rely upon the Projections in connection with its financial analysis and opinion summarized under “The Merger (Proposal 1)—Opinion of Centerview Partners LLC.”

In preparing the Projections, Chinook management assumed (1) that Chinook pursues the development and commercialization within the United States of atrasentan (for Indication 1 and Indication 2), BION-1301, CHK-336, and a preclinical program through its partnership with Ionis (and finances this with the proceeds of equity financings, raising an aggregate of approximately $500.0 million in net proceeds through equity financing in the first three years of the Projections); (2) that Chinook receives revenue from partnerships for the development and commercialization of certain of these programs outside of the United States, and does not receive revenue from direct sales outside of the United States; and (3) that Chinook does not earn revenue from the sale of any products other than those described above, or incur any material development, regulatory, manufacturing or sales or marketing costs associated with any such products or product development programs. The probability of success attributed to all indications for each product candidate in the Projections and the corresponding anticipated product candidate launch timelines are based on management assumptions.

The Projections were not prepared with a view to public disclosure or toward compliance with generally accepted accounting principles as applied in the United States (“GAAP”), the published guidelines of the SEC regarding projections and forward-looking statements or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. Furthermore, our independent auditor has not examined, reviewed, compiled or otherwise performed any procedures with respect to the Projections, and accordingly assumes no responsibility for, and expresses no opinion or other form of assurance on, the Projections. By including the Projections in this proxy statement, neither Chinook nor any of its affiliates, officers, directors, advisors or other representatives has made or makes any representation to any person regarding the information included in the Projections or the ultimate performance of Chinook or any of its affiliates compared to the information contained in the Projections. Chinook has not made and makes no representation to Novartis or any Chinook stockholder, in the Merger Agreement or otherwise, concerning the Projections or regarding Chinook’s actual performance compared to the Projections or that the Projections will be achieved. Chinook urges all of its stockholders not to place undue reliance on the Projections and to evaluate them together with Chinook’s most recent SEC filings and the historical financial statements and other information regarding Chinook contained therein.

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Forecasting the future cash flows associated with the development and commercialization of products in the clinical and early commercialization stages is a highly speculative endeavor. Although the Projections are presented with numerical specificity, the Projections reflect numerous variables, assumptions and estimates as to future events, including assumptions and estimates relating to Chinook’s ability to raise substantial amounts of capital in equity financing transactions in order to bring its product candidates through clinical trials, manufacturing and commercialization and to continue operating its business; the probability of success of clinical development and FDA approval of its product candidates and the timing of clinical trials, regulatory approval and commercial launch of these products; market demand for, and pricing of, its products; market size; market share; competition; reimbursement; distribution; estimated costs and expenses; contractual relationships; effective tax rate; utilization of net operating losses; and other relevant factors relating to Chinook’s long-term operating plan, as well as future economic, competitive and regulatory conditions and financial market conditions, all of which are highly uncertain, difficult or impossible to predict and many of which are beyond Chinook’s control. Chinook’s stockholders are urged to review Chinook’s SEC filings for a description of risk factors with respect to Chinook’s business. The Projections also reflect assumptions as to certain business decisions and general economic conditions that are subject to change. In addition, the Projections do not take into account any circumstances or events occurring after the date that they were prepared and do not give effect to the Merger. As a result, there can be no assurance that the Projections will be realized, and actual results may be materially better or worse than those contained in the Projections.

Except to the extent required by applicable law, we do not intend, and expressly disclaim any responsibility, to update or otherwise revise or reconcile the Projections to reflect circumstances existing after the date when Chinook prepared the Projections or to reflect the occurrence of future events or changes in general economic or industry conditions, even in the event that any of the assumptions underlying the Projections are shown not to be appropriate. Since the Projections cover multiple years, such information by its nature becomes less predictive with each successive year.

In light of the foregoing factors and the uncertainties inherent in the Projections, our stockholders are cautioned not to place undue reliance on the Projections included in this proxy statement.

Certain of the measures included in the Projections are non-GAAP financial measures, as noted below. Non-GAAP financial measures should not be considered in isolation from, or as a substitute for or superior measure to, financial information presented in compliance with GAAP. Chinook’s stockholders should also note that these non-GAAP financial measures presented in this proxy statement have no standardized meaning prescribed by GAAP, and therefore have limits in their usefulness. Because of the non-standardized definitions, the non-GAAP financial measures as used by Chinook in this proxy statement and the accompanying footnotes may be calculated differently from, and therefore may not be comparable to, similarly titled amounts used by other companies.

The following tables present a summary of the risk-adjusted management Projections (dollars in millions):

Opinion of Centerview Partners LLC

On June 11, 2023, Centerview rendered to the Board its oral opinion, subsequently confirmed in a written opinion dated June 11, 2023, that, as of such date and based upon and subject to various assumptions made,

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procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, the Total Per Share Consideration to be paid to the holders of common stock (other than as specified in such opinion) pursuant to the Merger Agreement was fair, from a financial point of view, to such holders.

The full text of Centerview’s written opinion, dated June 11, 2023, which describes the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion, is attached as Annex B and is incorporated herein by reference. The summary of the written opinion of Centerview set forth below is qualified in its entirety by the full text of Centerview’s written opinion attached as Annex B. Centerview’s financial advisory services and opinion were provided for the information and assistance of the Board (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transaction and Centerview’s opinion only addressed the fairness, from a financial point of view, as of the date thereof, to the holders of common stock (other than as specified in such opinion) of the Total Per Share Consideration to be paid to such holders pursuant to the Merger Agreement. Centerview’s opinion did not address any other term or aspect of the Merger Agreement or the Transaction and does not constitute a recommendation to any stockholder of Chinook or any other person as to how such stockholder or other person should vote with respect to the Merger or otherwise act with respect to the Transaction or any other matter.

The full text of Centerview’s written opinion should be read carefully in its entirety for a description of the assumptions made, procedures followed, matters considered, and qualifications and limitations upon the review undertaken by Centerview in preparing its opinion.

In connection with rendering the opinion described above and performing its related financial analyses, Centerview reviewed, among other things:

Centerview also participated in discussions with members of senior management and representatives of Chinook regarding their assessment of the Internal Data, and conducted such financial studies and analyses and took into account such information as Centerview deemed appropriate.

Centerview assumed, without independent verification or any responsibility therefor, the accuracy and completeness of the financial, legal, regulatory, tax, accounting and other information supplied to, discussed with, or reviewed by Centerview for purposes of its opinion and, with Chinook’s consent, Centerview relied upon

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such information as being complete and accurate. In that regard, Centerview assumed, at Chinook’s direction, that the Internal Data (including, without limitation, the Projections) were reasonably prepared on bases reflecting the best currently available estimates and judgments of the management of Chinook as to the matters covered thereby and Centerview relied, at Chinook’s direction, on the Internal Data for purposes of Centerview’s analysis and opinion. Centerview expressed no view or opinion as to the Internal Data or the assumptions on which it was based. In addition, at Chinook’s direction, Centerview did not make any independent evaluation or appraisal of any of the assets or liabilities (contingent, derivative, off-balance-sheet or otherwise) of Chinook, nor was Centerview furnished with any such evaluation or appraisal, and was not asked to conduct, and did not conduct, a physical inspection of the properties or assets of Chinook. Centerview assumed, at Chinook’s direction, that the final executed Merger Agreement and the final executed CVR Agreement would not differ in any respect material to Centerview’s analysis or opinion from the Draft Agreements reviewed by Centerview. Centerview also assumed, at Chinook’s direction, that the Transaction will be consummated on the terms set forth in the Merger Agreement and the CVR Agreement and in accordance with all applicable laws and other relevant documents or requirements, without delay or the waiver, modification or amendment of any term, condition or agreement, the effect of which would be material to Centerview’s analysis or Centerview’s opinion and that, in the course of obtaining the necessary governmental, regulatory and other approvals, consents, releases and waivers for the Transaction, no delay, limitation, restriction, condition or other change will be imposed, the effect of which would be material to Centerview’s analysis or Centerview’s opinion. Centerview did not evaluate and did not express any opinion as to the solvency or fair value of Chinook, or the ability of Chinook to pay its obligations when they come due, or as to the impact of the Transaction on such matters, under any state, federal or other laws relating to bankruptcy, insolvency or similar matters. Centerview is not a legal, regulatory, tax or accounting advisor, and Centerview expressed no opinion as to any legal, regulatory, tax or accounting matters.

Centerview’s opinion expressed no view as to, and did not address, Chinook’s underlying business decision to proceed with or effect the Transaction, or the relative merits of the Transaction as compared to any alternative business strategies or transactions that might be available to Chinook or in which Chinook might engage. Centerview’s opinion was limited to and addressed only the fairness, from a financial point of view, as of the date of Centerview’s written opinion, to the holders of the common stock (other than as specified in such opinion) of the Total Per Share Consideration to be paid to such holders pursuant to the Merger Agreement and the CVR Agreement. For purposes of its opinion, Centerview was not asked to, and Centerview did not, express any view on, and its opinion did not address, any other term or aspect of the Merger Agreement, the CVR Agreement or the Transaction, including, without limitation, the structure or form of the Transaction, the form or terms of the CVRs with respect to transferability, illiquidity or otherwise, or any other agreements or arrangements contemplated by the Merger Agreement or entered into in connection with or otherwise contemplated by the Transaction, including, without limitation, the fairness of the Transaction or any other term or aspect of the Transaction to, or any consideration to be received in connection therewith by, or the impact of the Transaction on, the holders of any other class of securities, creditors or other constituencies of Chinook or any other party. In addition, Centerview expressed no view or opinion as to the fairness (financial or otherwise) of the amount, nature or any other aspect of any compensation to be paid or payable to any of the officers, directors or employees of Chinook or any party, or class of such persons in connection with the Transaction, whether relative to the Total Per Share Consideration to be paid to the holders of the common stock (other than as specified in such opinion) pursuant to the Merger Agreement or otherwise. Centerview’s opinion was necessarily based on financial, economic, monetary, currency, market and other conditions and circumstances as in effect on, and the information made available to Centerview as of, the date of Centerview’s written opinion, and Centerview does not have any obligation or responsibility to update, revise or reaffirm its opinion based on circumstances, developments or events occurring after the date of Centerview’s written opinion. Centerview’s opinion does not constitute a recommendation to any stockholder of the Company or any other person as to how such stockholder or other person should vote with respect to the Merger or otherwise act with respect to the Transaction or any other matter. Centerview’s financial advisory services and its written opinion were provided for the information and assistance of the Board (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transaction. The issuance of Centerview’s opinion was approved by the Centerview Partners LLC Fairness Opinion Committee.

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Summary of Centerview’s Financial Analysis

The following is a summary of the material financial analyses prepared and reviewed with the Board in connection with Centerview’s opinion, dated June 11, 2023. The summary set forth below does not purport to be a complete description of the financial analyses performed or factors considered by, and underlying the opinion of, Centerview, nor does the order of the financial analyses described represent the relative importance or weight given to those financial analyses by Centerview. Centerview may have deemed various assumptions more or less probable than other assumptions, so the reference ranges resulting from any particular portion of the analyses summarized below should not be taken to be Centerview’s view of the actual value of Chinook. In performing its analyses, Centerview made numerous assumptions with respect to industry performance, general business and economic conditions and other matters, many of which are beyond the control of Chinook or any other parties to the Transaction. None of Chinook, Novartis, Merger Sub or Centerview or any other person assumes responsibility if future results are materially different from those discussed. Any estimates contained in these analyses are not necessarily indicative of actual values or predictive of future results or values, which may be significantly more or less favorable than as set forth below. In addition, analyses relating to the value of Chinook do not purport to be appraisals or reflect the prices at which Chinook may actually be sold. Accordingly, the assumptions and estimates used in, and the results derived from, the financial analyses are inherently subject to substantial uncertainty. Except as otherwise noted, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before June 9, 2023 (the last trading day before the public announcement of the Transaction) and is not necessarily indicative of current market conditions.

Analysis of Consideration

Centerview conducted an analysis of the Total Per Share Consideration to be paid to the holders of common stock (other than as specified in such opinion) pursuant to the Merger Agreement and the CVR Agreement. Such consideration is equal to (a) $40.00 per share in cash plus (b) one CVR per share, as set forth in, and subject to and in accordance with the terms and conditions of, the CVR Agreement, representing the right to receive $2.00 in cash upon the achievement of Milestone 1 and $2.00 in cash upon the achievement of Milestone 2, and in each case, without interest and subject to any applicable tax withholding, as described more fully under the section titled “Contingent Value Rights Agreement.”

For analytical purposes, Centerview calculated an illustrative risk-adjusted net present value for CVR of $1.87, assuming that CVR holders receive a gross payment of $4.00 per one CVR upon the achievement of the Milestones, which was risk-adjusted based solely on the assessments of Chinook management as to the probability and the timing of achievement of the Milestones and realizing the Milestone Payments, and was discounted to present value as of June 30, 2023 using a discount rate of 12.5% (based on the midpoint of the range suggested by Centerview’s analysis of Chinook’s weighted average cost of capital).

Solely for purposes of the financial analyses summarized below, the term “Implied Consideration Value” refers to an aggregate assumed implied per share value of the Total Per Share Consideration of $41.87 per share, representing, on a per Share basis, $40.00 upfront closing amount, taken together (and not separately) with the illustrative risk-adjusted net present value of the CVR of $1.87 per CVR, as set forth above. However, there is no guarantee that the conditions for the Milestone Payments will be satisfied, and if satisfied, when such conditions will be satisfied.

Discounted Cash Flow Analysis

Centerview performed a discounted cash flow analysis of Chinook based on the Projections, which reflect certain assumptions, including projected future financing needs of Chinook. A discounted cash flow analysis is a traditional valuation methodology used to derive a valuation of an asset or set of assets by calculating the “present value” of estimated future cash flows of the asset or set of assets. “Present value” refers to the current value of future cash flows and is obtained by discounting those future cash flows by a discount rate that takes

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into account macroeconomic assumptions and estimates of risk, the opportunity cost of capital, expected returns and other appropriate factors.

In performing this analysis, Centerview calculated a range of equity values for the common stock by (a) discounting to present value as of June 30, 2023 using discount rates ranging from 11.5% to 13.5% (based on Centerview’s analysis of Chinook’s weighted average cost of capital) and using a mid-year convention: (i) the forecasted risk-adjusted, after-tax unlevered free cash flows of Chinook over the period beginning on July 1, 2023 and ending on December 31, 2043, as set forth in the Projections, utilized by Centerview at the direction of Chinook management and as approved by the Board for use by Centerview as set forth in the section captioned “Certain Chinook Unaudited Prospective Financial Information,” (ii) an implied terminal value of Chinook, calculated by Centerview by assuming that (as directed by Chinook management) Chinook’s unlevered free cash flows would decline in perpetuity after December 31, 2043 at a rate of free cash flow decline of 25% year over year, and (iii) tax savings from usage of Chinook’s estimated federal net operating losses and Chinook’s estimated future losses, as provided by Chinook management, (b) adding to the foregoing results, Chinook’s estimated cash balance (including investments) as of June 30, 2023, as provided by Chinook management.

Centerview then calculated a range of implied equity values per share of common stock (a) by dividing the result of the foregoing calculations by Chinook’s fully diluted outstanding shares of common stock calculated on a treasury stock method basis (taking into account outstanding in-the-money stock options, unvested RSUs, unvested PSUs and warrants) as of June 7, 2023 and as set forth in the Internal Data and (b) taking into account the impact of assumed equity raises in 2023 and 2025 on a per share basis, as instructed by Chinook management. The resulting range of implied equity values per share of common stock was $32.00 to $38.35, rounded to the nearest $0.05. Centerview then compared this range to the Implied Consideration Value of $41.87 per share to be paid to the holders of common stock (other than as specified in such opinion) pursuant to the Merger Agreement and the CVR Agreement.

Other Factors

Centerview noted for the Board certain additional factors solely for reference and informational purposes, including, among other things, the following:

General

The preparation of a financial opinion is a complex analytical process involving various determinations as to the most appropriate and relevant methods of financial analysis and the application of those methods to the particular

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circumstances and, therefore, a financial opinion is not readily susceptible to summary description. In arriving at its opinion, Centerview did not draw, in isolation, conclusions from or with regard to any factor or analysis that it considered. Rather, Centerview made its determination as to fairness on the basis of its experience and professional judgment after considering the results of all of the analyses.

Centerview’s financial analyses and opinion were only one of many factors taken into consideration by the Board in its evaluation of the Transaction. Consequently, the analyses described above should not be viewed as determinative of the views of the Board or management of Chinook with respect to the Total Per Share Consideration or as to whether the Board would have been willing to determine that a different consideration was fair. The consideration for the Transaction was determined through arm’s-length negotiations between Chinook and Novartis and was approved by the Board. Centerview provided advice to Chinook during these negotiations. Centerview did not, however, recommend any specific amount of consideration to Chinook or the Board or that any specific amount of consideration constituted the only appropriate consideration for the transaction.

Centerview is a securities firm engaged directly and through affiliates and related persons in a number of investment banking, financial advisory and merchant banking activities. In the two years prior to the date of its written opinion, except for its current engagement with respect to the Transaction, Centerview had not been engaged to provide financial advisory or other services to Chinook, and Centerview did not receive any compensation from Chinook during such period. In the two years prior to the date of Centerview’s written opinion, Centerview had not been engaged to provide financial advisory or other services to Novartis or Merger Sub, and Centerview did not receive any compensation from Novartis during such period. Centerview may provide financial advisory and other services to or with respect to Chinook or Novartis or their respective affiliates in the future, for which Centerview may receive compensation. Certain (i) of Centerview’s and its affiliates’ directors, officers, members and employees, or family members of such persons, (ii) of Centerview’s affiliates or related investment funds and (iii) investment funds or other persons in which any of the foregoing may have financial interests or with which they may co-invest, may at any time acquire, hold, sell or trade, in debt, equity and other securities or financial instruments (including derivatives, bank loans or other obligations) of, or investments in, Chinook, Novartis, or any of their respective affiliates, or any other party that may be involved in the Transaction.

The Board selected Centerview as its financial advisor in connection with the Transaction based on Centerview’s reputation and experience. Centerview is an internationally recognized investment banking firm that has substantial experience in transactions similar to the Transaction.

In connection with Centerview’s services as the financial advisor to the Board, Chinook has agreed to pay Centerview an aggregate fee of approximately $58 million, $1 million of which was payable upon the rendering of Centerview’s opinion and the remainder of which is payable contingent upon consummation of the Transaction. In addition, Chinook has agreed to reimburse certain of Centerview’s expenses arising, and to indemnify Centerview against certain liabilities that may arise, out of Centerview’s engagement.

Financing of the Merger

The Merger is not conditioned on any financing arrangements or contingencies. We anticipate that the total amount of funds necessary to consummate the Merger and the related transactions, including the funds needed to (i) pay our stockholders the amounts due to them under the Merger Agreement; (ii) make payments in respect of Chinook’s outstanding equity-based awards pursuant to the Merger Agreement; and (iii) pay all fees and expenses related to the Merger, will be funded through cash on hand available to Novartis.

Interests of Chinook’s Directors and Executive Officers in the Merger

When considering the recommendation of our Board that you vote for the proposal to adopt the Merger Agreement, you should be aware that our directors and executive officers may have interests in the Merger that are different from, or in addition to, your interests as a stockholder. Our Board was aware of these interests in approving the Merger Agreement and the Merger and in recommending that the Merger Agreement be adopted by our stockholders.

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For this purpose, (i) our directors are Srinivas Akkaraju, Jerel Davis, William M. Greenman, Michelle Griffin, Ross Haghighat (who ceased being a member of our Board following the expiration of his term on June 9, 2023), Mahesh Krishman, Dolca Thomas, and Robert W. Azelby, and (ii) our executive officers are Eric Dobmeier, Eric Bierkholt, Tom Frohlich, Andrew King, and Andrew Oxtoby.

Treatment of Director and Executive Officer Common Stock

As is the case for our stockholders generally, our directors and executive officers will be entitled to receive (i) $40.00 in cash without interest and subject to any applicable withholding taxes, and (ii) one CVR for each share of our common stock that they own at the Effective Time. For information regarding beneficial ownership of our common stock by each of our current directors, our named executive officers and all directors and executive officers as a group, see the section entitled “Security Ownership of Certain Beneficial Owners and Management” beginning on page 94.

Treatment of Equity Awards

Stock Options. As of immediately prior to the Effective Time of the Merger, each stock option to purchase shares of our common stock that is outstanding but not then vested or exercisable will become immediately vested and exercisable in full. At the Effective Time, each stock option that is outstanding and unexercised will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such stock option, (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the excess, if any, of (A) the Per Share Cash Consideration over (B) the per share exercise price of such stock option, and (ii) one CVR. However, if per share the exercise price of such stock option is equal to or greater than the Per Share Cash Consideration, such stock option will be canceled without any cash payment, CVR or other consideration being made in respect thereof.

The following table sets forth, based on vested and unvested stock options outstanding as of July 3, 2023, the cash proceeds that each of our directors and executive officers would receive in respect of such stock options (i) based on the excess, if any, of the Per Share Cash Consideration of $40.00 over the applicable per share exercise price, and (ii) in connection with the CVR, assuming that both of the Milestones are achieved in the applicable Milestone Period:

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Restricted Stock Units. As of immediately prior to the Effective Time, each RSU that is outstanding will become immediately vested in full. At the Effective Time, each outstanding RSU will be canceled and converted into the right to receive (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the Per Share Cash Consideration and (ii) one CVR.

The following table sets forth, based on RSUs outstanding as of July 3, 2023, the cash proceeds that each of our directors and executive officers would receive in respect of such RSUs (i) based on the Per Share Cash Consideration of $40.00 per share, and (ii) in connection with the CVR, assuming that both of the Milestones are achieved in the applicable Milestone Period:

Performance Stock Units. As of immediately prior to the Effective Time, each PSU that is outstanding will become immediately vested in full for the maximum number of shares thereunder. At the Effective Time, each outstanding PSU will be canceled and converted into the right to receive (i) an amount in cash, without interest and subject to applicable withholding taxes, equal to the Per Share Cash Consideration and (ii) one CVR.

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The following table sets forth, based on PSUs outstanding as of July 3, 2023, the cash proceeds that each of our directors and executive officers would receive in respect of such PSUs (i) based on the Per Share Cash Consideration of $40.00 per share, and (ii) in connection with the CVR, assuming that both of the Milestones are achieved in the applicable Milestone Period:

Cash Payments in Lieu of Equity Awards. In addition to the above, in lieu of the equity awards that our non-employee directors otherwise would have been granted in connection with our annual shareholder meeting held on June 9, 2023, each non-employee director will be entitled to receive, subject to such director’s continued service through the consummation of the Merger, (i) in lieu of any stock options that would have been granted, a cash payment equal to the number of shares of Chinook common stock underlying the stock options that would have been granted, multiplied by the excess of the Per Share Cash Consideration of $40.00 over the closing price of the Company’s common stock on June 9, 2023 ($23.99 per share), (ii) in lieu of any RSUs that would have been granted, a cash payment equal to the number of shares of Chinook common stock with respect to which RSUs would have been granted, multiplied by the Per Share Cash Consideration of $40.00 per share, and (iii) one CVR for each share of Chinook common stock that would have been subject to such stock options and RSUs.

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The following table reflects the cash proceeds (i) based on the Per Share Cash Consideration of $40.00 per share (less the closing price of the Company’s common stock on June 9, 2023 per underlying share in the case of any stock options that would have been granted), and (ii) in connection with the CVR, assuming that both of the Milestones are achieved in the applicable Milestone Period:

Employee Stock Purchase Plan

The current offering period under the ESPP began on May 16, 2023 and is scheduled to end on November 15, 2023. If the Merger closing occurs prior to that date, shares of our common stock will be issued to the participants in the ESPP pursuant to the terms of the ESPP on the tenth business day prior to the date on which the Effective Time occurs, and such shares will be treated like all other outstanding shares of our common stock in the Merger. In such case, the number of shares issued to each participant under the ESPP will be determined by dividing (i) the accumulated amount of payroll deductions that the participant has contributed to his or her ESPP account during the current offering period (the “ESPP Contributions”) by (ii) 85% of the lower of (a) the closing price of a share of our common stock on the first day of the current offering period, which was $22.35, or (b) the closing price of a share of our common stock on the applicable purchase date.

Payments Upon Termination or Change of Control Provisions

Executive Employment Agreements

Each of our executive officers has entered into an executive employment agreement which provides that, if the executive officer’s employment is terminated by us without “Cause” or the executive officer resigns for “Good reason,” in either case, during the period commencing on the signing date of the Merger Agreement and ending on the 12 month anniversary of the date on which the Effective Time occurs, then the executive officer will be eligible to receive the following, in exchange for a release of claims:

The executive employment agreements provide that if an executive officer receives an amount subject to the excise tax under Section 4999 of the Code, the amount of the payments to be made to the executive officer will

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be reduced to the extent such reduction would result in a greater amount of after-tax proceeds. However, this cutback would be applied only after taking into account any tax reimbursement payment to the executive officer under the Tax Reimbursement Plan as discussed below in the section entitled “ —Tax Reimbursement Plan.”

In addition, pursuant to the terms of the Merger Agreement, the executive officers would be entitled to a prorated portion of their target annual bonus for calendar 2023 if they are terminated without “Cause” or they resign for “Good Reason” prior to the time that the 2023 annual bonus is paid.

For purposes of the executive employment agreements:

Tax Reimbursement Plan

Prior to the Merger Closing, we intend to adopt a tax reimbursement plan (the “Tax Reimbursement Plan”) providing for payments to certain individuals whom we have determined could reasonably be expected to be a

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“disqualified individual” (as defined in Section 280G of the Code) in the event that such individual is subject to the excise tax under Section 4999 of the Code, in an amount that would provide the recipient with the same after-tax amount that the recipient otherwise would have received had such excise tax not applied. The maximum aggregate amount payable under the Tax Reimbursement Plan will not exceed $11,600,000.

Non-Employee Director Fees

Pursuant to the terms of the Merger Agreement, each non-employee member of the Board will receive a cash payment equal to the unpaid cash retainer for the calendar quarter that includes the Merger closing, without pro-ration, to be paid no later than 30 days following the Effective Time.

In addition, in connection with Mr. Haghighat’s ceasing being a member of our Board following the expiration of

his term on June 9, 2023, we entered into a consulting agreement with Mr. Haghighat, pursuant to which he has agreed to provide advisory services as reasonably requested by Mr. Dobmeier for a one-year period, in exchange for the payment of $27,884.62 (which represents the remainder of his 2023 Board compensation) within 30 days following the date of the consulting agreement.

Quantification of Payments and Benefits to Chinook Named Executive Officers

For purposes of this proxy statement, our named executive officers consist of (i) Eric Dobmeier, President and Chief Executive Officer; (ii) Tom Frohlich, Chief Operating Officer; (iii) Andrew King, Chief Scientific Officer and (iv) Eric Bjerkholt, Chief Financial Officer. The compensation that may be paid or become payable to our named executive officers in connection with the Merger is subject to approval, on an advisory (non-binding) basis, by our stockholders, as described below in the section entitled “Advisory Vote on Named Executive Officer Merger-Related Compensation (Proposal 2)” on page 92.

The table below and its footnotes show the estimated amounts of payments and benefits that each named executive officer would receive in connection with the Merger, assuming that (i) the Merger was consummated and each such named executive officer’s employment was terminated by Chinook without Cause or by the named executive officer with Good Reason (each of which we refer to as a “qualifying termination”), in each case on July 3, 2023 and (ii) that both the Milestones for the CVR are achieved in full, so that the per share price for our common stock for this purpose equals $44.00.

The calculations in the table below do not include amounts the named executive officers would have been entitled to receive regardless of whether the Effective Time has occurred, that were vested as of July 3, 2023, or amounts under contracts, agreements, plans or arrangements to the extent they do not discriminate in scope, terms or operation in favor of an officer and that are available generally to all of our salaried employees.

The estimated amounts below are based on multiple assumptions that may not actually occur, including assumptions described in this proxy statement. In addition, certain amounts will vary depending on the actual date of closing of the Merger and actual date of the named executive officer’s termination of employment. As a result, the actual amounts, if any, to be received by an applicable individual may differ in material respects from the amounts set forth below.

Golden Parachute Compensation

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Indemnification of and Insurance for Directors and Executive Officers

Pursuant to the terms of the Merger Agreement, our directors and executive officers will be entitled to certain ongoing indemnification and coverage for a period of six years following the Effective Time under directors’ and officers’ liability insurance policies from the Surviving Corporation. This indemnification and insurance coverage is further described in the section of this proxy statement captioned “The Merger Agreement—  Indemnification and Insurance.”

Material U.S. Federal Income Tax Consequences of the Merger

The following discussion is a summary of certain anticipated U.S. federal income tax consequences of the Merger to U.S. holders (as defined below) whose shares of common stock are converted into the right to receive the Total Per Share Consideration pursuant to the Merger. This discussion is based upon the Code, Treasury Regulations promulgated under the Code, rulings and other published positions of the Internal Revenue Service (the “IRS”) and judicial decisions, all as in effect on the date of this proxy statement and all of which are subject to change or differing interpretations, possibly with retroactive effect. Any such change, which may or may not be retroactive, could alter the tax consequences described herein. This discussion is limited to holders who hold their shares of our common stock as “capital assets” within the meaning of Section 1221 of the Code (generally, property held for investment purposes) and exchange their shares for the Total Per Share Consideration.

This discussion does not address all of the tax consequences that may be relevant to holders in light of their particular facts and circumstances, nor does it address any consequences to holders subject to special rules under the U.S. federal income tax laws, such as:

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This discussion does not address any U.S. federal tax consequences other than those pertaining to the income tax (such as estate, gift or other non-income tax consequences) or any state, local or non-U.S. income or non-income tax consequences, or the consequences of the Medicare tax on net investment income. If a partnership (including an entity or arrangement treated as a partnership for U.S. federal income tax purposes) is a beneficial owner of shares of our common stock, the U.S. federal income tax treatment of a partner in such partnership will generally depend upon the status of the partner and the activities of the partnership. Partnerships holding shares of our common stock and partners therein should consult their own tax advisors regarding the consequences of the Merger to their particular circumstances.

No ruling has been or will be sought from the IRS regarding the U.S. federal income tax consequences of the Merger described herein. This summary is not binding on the IRS or a court, and there can be no assurance that the tax consequences described in this summary will not be challenged by the IRS or that they would be sustained by a court if so challenged.

HOLDERS SHOULD CONSULT THEIR OWN TAX ADVISORS CONCERNING THE U.S. FEDERAL INCOME TAX CONSEQUENCES RELATING TO THE MERGER IN LIGHT OF THEIR PARTICULAR CIRCUMSTANCES AND ANY CONSEQUENCES ARISING UNDER ANY STATE, LOCAL, NON-U.S. OR OTHER TAX LAWS.

U.S. Holders

For purposes of this discussion, a “U.S. holder” means a beneficial owner of shares of our common stock that is, for U.S. federal income tax purposes:

Consequences of the Merger

The exchange of shares of our common stock pursuant to the Merger for the Total Per Share Consideration will be a taxable transaction for U.S. federal income tax purposes. The timing and character of the gain or loss a U.S. holder will recognize as a result of the Merger is subject to significant uncertainty. The installment method of reporting any gain attributable to the receipt of the CVRs or the Milestone Payments ultimately received in respect of the CVRs, if any, will not be available because the shares of our common stock are traded on an established securities market. The receipt of the CVRs pursuant to the Merger may be treated as either a “closed transaction” or as an “open transaction” for U.S. federal income tax purposes, each as discussed in more detail below.

There is no legal authority expressly addressing whether contingent payment rights with characteristics similar to the rights under the CVRs are to be treated as either open transactions or closed transactions, and this determination is inherently factual in nature. Accordingly, U.S. holders are urged to consult their own tax advisors regarding this issue. The receipt of the CVRs would generally be treated as an “open transaction” if the value of the CVRs cannot be “reasonably ascertained.” Treasury regulations state that only in “rare and extraordinary” cases would the value of contingent payment obligations not be reasonably ascertainable and, therefore, be subject to the open transaction method. Under treasury regulations addressing contingent payment

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obligations analogous to the CVRs, if the fair market value of the CVRs is reasonably ascertainable, a U.S. holder should treat the transaction as a closed transaction and include the fair market value of the CVRs as additional consideration received in the Merger for purposes of determining gain or loss. It is possible, but unlikely, that the CVRs could be treated as debt instruments for U.S. federal income tax purposes. The discussion below does not address the tax consequences of such a characterization and assumes that the CVRs are not treated as debt instruments for U.S. federal income tax purposes.

Except as otherwise required pursuant to applicable law, we and Novartis intend to treat U.S. holders’ receipt of the CVRs as an “open transaction” for U.S. federal income tax purposes, and the Milestone Payments as additional consideration for the U.S. holders’ shares of our common stock.

The following sections discuss the possible tax treatment if the receipt of the Total Per Share Consideration pursuant to the Merger is treated as a closed transaction or an open transaction.

U.S. holders are urged to consult their own tax advisors regarding the proper characterization, method of tax accounting and tax reporting with respect to receipt of a CVR under the closed transaction method or open transaction method, as applicable in their respective case.

Treatment as Open Transaction

We and Novartis intend to treat the U.S. holders’ receipt of the CVRs as an open transaction for U.S. federal income tax purposes, and their receipt of the Milestone Payments as additional consideration for their shares of our common stock. If the receipt of a CVR pursuant to the Merger is treated as an open transaction for U.S. federal income tax purposes, the fair market value of the CVR will not be treated as additional consideration for the shares of our common stock at the time the CVR is received, and the U.S. holder will not have any tax basis in the CVR. Instead, the U.S. holder will take the Milestone Payments into account when made or deemed made in accordance with the U.S. holder’s regular method of accounting for U.S. federal income tax purposes. Generally, a portion of such payments will be treated as imputed interest, as described in more detail below, and the balance as additional consideration recognized in exchange for the shares of our common stock. Although not entirely clear, the cash consideration received in the Merger and the portion of the Milestone Payment that is not treated as imputed interest will generally be applied first against a U.S. holder’s adjusted tax basis in the shares of our common stock and any excess thereafter treated as gain. A U.S. holder will recognize loss with respect to a share of our common stock to the extent that the U.S. holder’s adjusted tax basis in such shares exceeds the cash consideration plus any Milestone Payments (less any portion of such payment required to be treated as imputed interest), if any, received or deemed received in respect of the CVR, and a U.S. holder may not be able to recognize such loss until the resolution of all contingencies under the CVR. Any such capital gain or loss will be long-term capital gain or loss if the U.S. holder’s holding period in the shares of Chinook common stock exceeds one year. The deductibility of capital losses is subject to limitations. Gain or loss generally will be determined separately for each block of shares of our common stock (that is, shares acquired at the same cost in a single transaction) exchanged pursuant to the Merger.

Treatment as Closed Transaction

If the receipt of a CVR is treated as, or determined to be, part of a closed transaction for U.S. federal income tax purposes, a U.S. holder who sells or exchanges shares of our common stock pursuant to the Merger generally will recognize gain or loss for U.S. federal income tax purposes in an amount equal to the difference, if any, between (i) the amount of cash received plus the fair market value (determined as of the Effective Time) of the CVRs received and (ii) the U.S. holder’s adjusted tax basis in the shares of our common stock sold or exchanged. No express guidance under current U.S. federal income tax law is available regarding the proper method for determining the fair market value of the CVRs. Such gain or loss should be capital gain or loss. Any capital gain or loss recognized will be long-term capital gain or loss if the U.S. holder’s holding period for such shares of our common stock exceeds one year as of the Effective Time. The deductibility of capital losses is subject to

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limitations. The amount of gain or loss generally will be determined separately for each block of shares of our common stock (that is, shares acquired at the same cost in a single transaction) exchanged pursuant to the Merger.

If the receipt of a CVR is treated as, or determined to be, part of a closed transaction, then the character of any gain, income or loss recognized by a U.S holder with respect to receipt of a Milestone Payment is uncertain. Such payments may be treated as payments with respect to a sale or exchange of a capital asset or as giving rise to ordinary income. Under this closed transaction method of reporting, a U.S. holder should recognize gain equal to the difference between any payment made with respect to a CVR (less any portion of such payment required to be treated as imputed interest, as described below) and the U.S. holder’s adjusted tax basis in the applicable CVR or, if the CVR expires without the Milestone being achieved, loss equal to the U.S. holder’s adjusted tax basis in the applicable CVR. A U.S. holder’s adjusted basis in a CVR generally will equal the CVR’s fair market value (determined as of the Effective Time). Any gain or loss will generally be long-term capital gain or loss if the U.S. holder has held the applicable CVR (or possibly the shares of our common stock in respect of which such CVR was received) for more than one year at the time of such payment or expiry. The deductibility of capital losses is subject to limitations.

Imputed Interest

Under either the “open transaction” or “closed transaction” treatment, a portion of any Milestone Payments may be treated as imputed interest that is ordinary income to a U.S. holder. The portion of any Milestone Payment made which will be treated as imputed interest will be determined at the time such payment is made and generally should equal the excess of (i) the amount of the Milestone Payment over (ii) the present value of such amount as of the Effective Time, calculated using the applicable federal rate as the discount rate. A U.S. holder must include in its taxable income imputed interest using such U.S. holder’s regular method of accounting for U.S. federal income tax purposes. U.S. holders are urged to consult their own tax advisors as to the application of the imputed interest rules to the receipt of any Milestone Payments.

Information Reporting and Backup Withholding

Information reporting and backup withholding (currently, at a rate of 24%) may apply to the proceeds received by a holder pursuant to the Merger, including any Milestone Payment. Backup withholding generally will not apply to (i) a U.S. holder that furnishes a correct taxpayer identification number and certifies that such U.S. holder is not subject to backup withholding on IRS Form W-9 (or a substitute successor form) or otherwise establishes an exemption from backup withholding. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules will be allowed as a refund or a credit against the holder’s U.S. federal income tax liability; provided that the required information is timely furnished to the IRS.

Tax information provided to a U.S. holder and the IRS on IRS Form 1099-B for the year of the Merger may reflect only the cash amounts paid to the U.S. holder on the Merger and not the fair market value of the U.S. holder’s interest in Milestone Payments made (or to be made) with respect to the CVRs. Accordingly, a U.S. holder that treats the Merger as a “closed transaction” for U.S. federal income tax purposes may receive an IRS Form 1099-B reporting an amount received that is less than the amount such U.S. holder will realize in the year of the Merger. In addition, any IRS Form 1099-B a U.S. holder receives with respect to Milestone Payments on the CVRs may reflect the entire amount of the Milestone Payments paid to the U.S. holder (except imputed interest) and therefore may not take into account the fact that the U.S. holder already included the value of such payments in such U.S. holder’s amount realized in the year of the Merger. As a result, U.S. holders reporting under this method should not rely on the amounts reported to them on IRS Forms 1099-B with respect to the Merger.

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HOLDERS OF OUR COMMON STOCK SHOULD CONSULT THEIR OWN TAX ADVISORS REGARDING THE U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE MERGER TO THEIR PARTICULAR CIRCUMSTANCES, INCLUDING THE APPLICABILITY OF ANY STATE, LOCAL, NON-U.S. OR OTHER TAX LAWS.

Regulatory Approvals

HSR Waiting Period. Under the HSR Act and the rules promulgated thereunder, certain transactions, including the Merger, may not be completed until notifications have been given and information furnished to the Antitrust Division and the FTC and all statutory waiting period requirements have been satisfied. Completion of the Merger is subject to the expiration or termination of the applicable waiting period under the HSR Act.

Under the HSR Act, the Merger may not be completed until the expiration of a 30-calendar day waiting period, which begins when Novartis and Chinook file PreMerger Notification and Report Forms under the HSR Act with the FTC and the Antitrust Division, unless such waiting period is earlier terminated by the FTC and the Antitrust Division. Novartis and Chinook will file their PreMerger Notification and Report Forms on or before June 30, 2023 in connection with the Merger, and the waiting period is expected to expire 30 calendar days after such filings. If prior to the expiration or termination of the waiting period either the FTC or the Antitrust Division issues a request for additional information or documentary material from Novartis or Chinook (commonly called a second request), the waiting period with respect to the Merger would be extended until the 30th calendar day following the date of Novartis’ and Chinook’s substantial compliance with that request. The FTC and the Antitrust Division may terminate the applicable waiting period at any time before its expiration. Absent Novartis’ and Chinook’s agreement, the acquisition can be blocked or further delayed by FTC or the Antitrust Division only pursuant to a court order.

Other Required Regulatory Approvals. Completion of the Merger may also be subject to the receipt of certain antitrust or competition approvals of other jurisdictions if in order to complete the Merger such approvals are required, or become required as a result of any regulatory authority asserting jurisdiction over the Merger.

At any time (regardless of whether before or after the expiration or termination of the statutory waiting periods under the HSR Act, or before or after the Effective Time), the Antitrust Division or the FTC, or foreign governmental authorities, may take action under applicable antitrust laws, including seeking to enjoin the completion of the Merger, to rescind the Merger or to conditionally permit completion of the Merger subject to regulatory conditions or other remedies. In addition, U.S. state attorneys general could take action under applicable antitrust laws as they deem necessary or desirable in the public interest, including, without limitation, seeking to enjoin the completion of the Merger or permitting completion subject to regulatory conditions. Private parties may also seek to take legal action under applicable antitrust laws to challenge the Merger under some circumstances. Although neither Chinook nor Novartis believes that the Merger will violate the antitrust laws, there can be no assurance that a challenge to the Merger on antitrust grounds will not be made or, if such a challenge is made, that it would not be successful.

Delisting and Deregistration of Chinook Common Stock

If the Merger is completed, our common stock will be delisted from the Nasdaq Global Select Market and deregistered under the Exchange Act.

The Merger Agreement Proposal

We are asking you to approve a proposal to adopt the Merger Agreement. For a detailed discussion of the terms and conditions of the Merger Agreement, see the section entitled “The Merger Agreement.” A copy of the Merger Agreement, including the form of CVR Agreement, is attached to this proxy statement as Annex A and is incorporated herein by reference.

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Vote Required and Board Recommendation

Under Delaware law, approval of the proposal to adopt the Merger Agreement requires the affirmative vote of holders of a majority of the outstanding shares of our common stock entitled to vote on the Merger Agreement at the Special Meeting or any adjournment or postponement thereof. Abstentions and broker non-votes, if any, will have the same effect as a vote “AGAINST” the proposal.

After considering various factors described in the section entitled “The Merger (Proposal 1)—Reasons for the Recommendation of our Board,” our Board has unanimously determined that the Merger Agreement, the CVR Agreement and the transactions contemplated by the Merger Agreement and the CVR Agreement, including the Merger, are fair to and in the best interests of Chinook and its stockholders, approved and declared advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, directed that the Merger Agreement be submitted to the Chinook stockholders for adoption at a Special Meeting and recommended that the Chinook stockholders adopt the Merger Agreement. Accordingly, our Board unanimously recommends that you vote “FOR” the proposal to adopt the Merger Agreement.

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THE MERGER AGREEMENT

The following is a summary of the material provisions of the Merger Agreement, a copy of which is attached to this proxy statement as Annex A and which is incorporated by reference into this proxy statement. This summary does not purport to be complete and may not contain all of the information about the Merger Agreement that is important to you. We encourage you to read carefully the Merger Agreement in its entirety, as the rights and obligations of the parties thereto are governed by the express terms of the Merger Agreement and not by this summary or any other information contained in this proxy statement.

Explanatory Note Regarding the Merger Agreement

The following summary of the Merger Agreement, and the copy of the Merger Agreement attached as Annex A to this proxy statement, are intended to provide information regarding the terms of the Merger Agreement and are not intended to provide any factual information about Chinook or modify or supplement any factual disclosures about Chinook in its public reports filed with the SEC. In particular, the Merger Agreement and the related summary are not intended to be, and should not be relied upon as, disclosures regarding any facts and circumstances relating to Chinook. The Merger Agreement contains representations and warranties by and covenants of Chinook, Novartis and Merger Sub that were made only for purposes of that agreement and as of specified dates. The representations, warranties and covenants in the Merger Agreement were made solely for the benefit of the parties to the Merger Agreement, may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures and being made for the purposes of allocating contractual risk between the parties to the Merger Agreement instead of establishing these matters as facts, and may be subject to contractual standards of materiality or material adverse effect applicable to the contracting parties that generally differ from those applicable to investors. In addition, information concerning the subject matter of the representations, warranties and covenants may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in Chinook’s public disclosures. The representations, warranties and covenants in the Merger Agreement and any descriptions thereof should be read in conjunction with the disclosures in Chinook’s periodic and current reports, proxy statements and other documents filed with the SEC. See the section entitled “Where You Can Find Additional Information.” Moreover, the description of the Merger Agreement below does not purport to describe all of the terms of such agreement and is qualified in its entirety by reference to the full text of such agreement, a copy of which is attached hereto as Annex A and is incorporated herein by reference.

Additional information about Chinook may be found elsewhere in this proxy statement and Chinook’s other public filings. See the section entitled “Where You Can Find Additional Information.”

Structure of the Merger; Certificate of Incorporation; Bylaws; Directors and Officers

At the Effective Time, Merger Sub will merge with and into Chinook, and the separate corporate existence of Merger Sub will cease. Chinook will be the Surviving Corporation in the Merger and will continue its corporate existence as a Delaware corporation and an indirect wholly owned subsidiary of Novartis.

At the Effective Time, the certificate of incorporation of the Surviving Corporation will be amended and restated in its entirety to be in the form attached as Exhibit B to the Merger Agreement and, as so amended and restated, such certificate of incorporation shall be the certificate of incorporation of the Surviving Corporation. Also at the Effective Time, the bylaws of the Surviving Corporation will be amended and restated in their entirety to be identical to the bylaws of Merger Sub as in effect immediately prior to the Effective Time (except that references to the name of Merger Sub will be replaced by references to Chinook Therapeutics, Inc.).

At the Effective Time, the individuals holding positions as directors of Merger Sub immediately before the Effective Time will become the initial directors of the Surviving Corporation, and the individuals holding positions as officers of Merger Sub immediately before the Effective Time will become the initial officers of the Surviving Corporation.

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When the Merger Becomes Effective

The closing of the Merger will take place at 8:00 a.m. Eastern time, no later than the fifth business day after the satisfaction (or, to the extent permitted by law, waiver by the party entitled thereto) of the conditions set forth in the Merger Agreement (other than those conditions that by their nature are to be satisfied at the closing, but subject to the satisfaction (or, to the extent permitted by law, waiver by the party entitled thereto) of such conditions), or at such other place, time and date as is agreed in writing by Novartis and Chinook.

On the closing date, Novartis, Merger Sub and Chinook will cause a certificate of merger to be filed with the Secretary of State of the State of Delaware. The Merger will become effective at the time the certificate of merger is duly filed with the Secretary of State of the State of Delaware or at such other time as Novartis and Chinook agree and specify in the certificate of merger.

As of the date of the filing of this proxy statement, the parties expect to complete the Merger in the second half of 2023. However, completion of the Merger is subject to the satisfaction or waiver of the conditions to the completion of the Merger, and factors outside the control of Chinook or Novartis may delay the completion of the Merger, or prevent it from being completed at all. There can be no assurances as to whether or when the Merger will be completed.

Effect of the Merger on our Common Stock

At the Effective Time, each issued and outstanding share of our common stock (other than Excluded Shares and Appraisal Shares), will be converted automatically into the right to receive the Total Per Share Consideration. The Total Per Share Consideration will be (i) the Per Share Cash Consideration, without interest and less applicable tax withholding, and (ii) one CVR per share.

At the Effective Time, each Excluded Share will be automatically canceled and will cease to exist, and no consideration will be delivered in exchange therefor.

Shares of our common stock that are issued and outstanding immediately prior to the Effective Time and that are held by any stockholders of Chinook who have not voted in favor of the adoption of the Merger Agreement (or consented to the Merger Agreement in writing) and who have properly demanded appraisal of such shares pursuant to, and who have otherwise complied with, Section 262 of the DGCL, will not be converted into the right to receive the Total Per Share Consideration, but instead, at the Effective Time, will be entitled to only such rights as are granted by Section 262. If any such holder fails to perfect or otherwise fails to comply with the applicable provisions of Section 262, waives, withdraws or loses the right to appraisal under Section 262 with respect to such Appraisal Shares or a court of competent jurisdiction determines that such holder is not entitled to the relief provided by Section 262, then such Appraisal Shares will be deemed to have been converted into, and have become exchangeable for, as of the Effective Time, the right to receive the Total Per Share Consideration, less any applicable tax withholding. Chinook has agreed to give prompt written notice to Novartis of any demands received by Chinook for appraisal of any shares of our common stock, any withdrawals of any such demands or any other instruments received by Chinook relating to the rights of appraisal of the holders of shares of our common stock, and Novartis will have the right to participate in and direct all negotiations and proceedings with respect to such demands. Chinook has agreed that it will not make any payment with respect to, or settle or offer to settle, or otherwise negotiate any such demands, or agree to do any of the foregoing, without the prior written consent of Novartis.

At the Effective Time, each issued and outstanding share of capital stock of Merger Sub will automatically be converted into one validly issued, fully paid and nonassessable share of common stock of the Surviving Corporation and shall constitute the only outstanding shares of capital stock of the Surviving Corporation.

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Treatment of Chinook Equity Awards; Employee Stock Purchase Plan

Stock Options. Immediately prior to the Effective Time, each stock option that is then outstanding but not then vested or exercisable will become immediately vested and exercisable in full. At the Effective Time, each stock option that is then outstanding will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such stock option, (i) an amount in cash, without interest and less any applicable tax withholding, equal to the excess, if any, of (A) the Per Share Cash Consideration over (B) the per share exercise price for such stock option, and (ii) one CVR issued pursuant to and in accordance with the CVR Agreement, provided, however, that if the exercise price per share of Chinook common stock of such stock option is equal to, or exceeds, the closing consideration, such stock option will be canceled for no consideration.

Restricted Stock Units. Immediately prior to the Effective Time, each RSU that is then outstanding but not then vested will become immediately vested in full. At the Effective Time, each RSU that is then outstanding will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such RSU, (i) the Per Share Cash Consideration, without interest and less any applicable tax withholding, and (ii) one CVR issued pursuant to and in accordance with the CVR Agreement.

Performance Stock Units. Immediately prior to the Effective Time, each PSU that is then outstanding but not then vested will become immediately vested in full for the maximum number of shares of Chinook common stock underlying such PSU. At the Effective Time, each PSU that is then outstanding will be canceled and converted into the right to receive, with respect to each share of Chinook common stock underlying such PSU, (i) the Per Share Cash Consideration, without interest and less any applicable tax withholding, and (ii) one CVR issued pursuant to and in accordance with the CVR Agreement.

2015 Employee Stock Purchase Plan. We have agreed that, during the term of the Merger Agreement, we will not permit any further offering periods to commence under the ESPP, and we will not allow participants in the ESPP to increase their payroll deductions from those in effect on the date of the Merger Agreement or allow anyone who is not a participant in the ESPP as of the date of the Merger Agreement to become a participant. We will terminate the ESPP effective as of the Effective Time, and if the applicable purchase date with respect to the current offering period would otherwise occur on or after the Effective Time, then such offering period will be shortened and the applicable purchase date with respect to such offering period will occur on the 10^th business day immediately preceding the date on which the Effective Time occurs.

Treatment of Outstanding Warrants

There are outstanding pre-funded warrants to purchase 4,642,856 shares of our common stock, with a weighted-average exercise price of $0.0001 per share and an outstanding common warrant to purchase 165 shares of our common stock (the “specified warrant”) with a weighted-average exercise price of $0.01 per share. Pursuant to the terms of the Merger Agreement and the pre-funded warrants, at the Effective Time, each outstanding pre-funded warrant will become exercisable by the holder thereof solely for the same Total Per Share Consideration as such holder would have been entitled to receive following the Effective Time if such holder had been, immediately prior to the Effective Time, the holder of the number of shares of Chinook common stock then issuable upon exercise in full of such warrant without regard to any limitations on exercise contained therein. Pursuant to the terms of the Merger Agreement and the specified warrant, if outstanding immediately prior to the Effective Time, the specified warrant be exercised automatically in whole as of such time pursuant to the net exercise provisions set forth in such warrant, and each share of Chinook common stock issuable pursuant to such automatic exercise of the specified warrant shall be issued by Chinook to the holder of the specified warrant and be outstanding immediately prior the Effective Time, and at the Effective Time, each such share of Chinook common stock shall automatically be converted into the right of the holder of such shares to receive the Total Per Share Consideration.

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Payment for Common Stock in the Merger

At or immediately after the Effective Time, Novartis will cause to be deposited to a bank or trust company reasonably acceptable to Chinook (the “Paying Agent”), cash necessary to pay the upfront cash consideration in respect of the shares of Chinook common stock and company warrants converted into the right to receive cash pursuant to the Merger Agreement (such cash, the “payment fund”). As promptly as reasonably practicable after the Effective Time, and in any event no later than two business days after the Effective Time, the Surviving Corporation or Novartis shall cause the Paying Agent to mail to each holder of record of a certificate or book-entry share that, immediately prior to the Effective Time, represented outstanding shares of Chinook common stock whose shares were converted into the right to receive the Total Per Share Consideration (1) a letter of transmittal and (2) instructions for effecting the surrender of certificates or book-entry shares formerly representing shares of our common stock in exchange for the Total Per Share Consideration. Upon (1) in the case of share certificates, surrender of such certificates (or if lost, stolen or destroyed, the making of an affidavit and such other documents as may reasonably be required by the Paying Agent) together with a duly executed letter of transmittal to the Paying Agent or (2) in the case of book-entry shares, receipt of an “agent’s message” by the Paying Agent, and delivery to the Paying Agent of such other documents as may reasonably be required by the Paying Agent, the holder of such certificates or book-entry shares, as applicable, will be entitled to receive the Per Share Cash Consideration in exchange for each share of Chinook common stock theretofore represented by such certificates or book-entry shares.

Any portion of the payment fund (and any interest or other income earned thereon) that remains undistributed as of the 12-month anniversary of the Merger closing date will be delivered to Novartis or its designated affiliate upon demand, and any former holder of Chinook common stock entitled to payment of the Total Per Share Consideration who has not yet complied with the provisions for exchange may thereafter look only to Novartis or any successor-in-interest of Novartis as a general creditor for payment of its claim for the Total Per Share Consideration (subject to applicable abandoned property, escheat and other similar law). Further, if any certificate or book-entry share has not been surrendered immediately prior to the date on which the Total Per Share Consideration in respect of such certificate or book-entry share would otherwise escheat to or become the property of any governmental entity, any Total Per Share Consideration related to such certificate or book-entry share will, to the extent permitted by applicable law, become the property of the Surviving Corporation or its designated affiliate, free and clear of any claims or interest of any person previously entitled thereto.

Representations and Warranties; Material Adverse Effect

The Merger Agreement contains representations and warranties made by Chinook, subject to certain exceptions in the Merger Agreement, in the confidential disclosure letter delivered in connection with the Merger Agreement and in certain of Chinook’s public filings, as to, among other things:

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The Merger Agreement also contains representations and warranties made by Novartis and Merger Sub, subject to certain exceptions in the Merger Agreement, as to, among other things:

Some of the representations and warranties in the Merger Agreement are qualified by materiality or knowledge qualifications or a “material adverse effect” qualification with respect to either Chinook or Novartis, as discussed below.

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For purposes of the description of the Merger Agreement, a “material adverse effect with respect to Chinook” means any change, event, condition, development, circumstance, state of facts or occurrence that individually or in the aggregate (i) has a material adverse effect on the business, assets, financial condition or results of operations of Chinook and its subsidiaries, taken as a whole, or (ii) prevents, materially impairs or materially delays Chinook from consummating the transactions contemplated by the Merger Agreement on a timely basis and in any event on or before the outside date; provided, that with respect to clause (i) only, none of the following will be deemed either alone or in combination to constitute, and except as otherwise provided for below none of the following will be taken into account in determining whether there has been, a material adverse effect with respect to Chinook:

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except (1) in the case of any of (a), (b), (c), (d) or (e) above, to the extent that Chinook and its subsidiaries, taken as a whole, are disproportionately affected thereby as compared with other participants in the industries in which Chinook and its subsidiaries operate (in which case only the incremental disproportionate impact or impacts may be taken into account in determining whether there has been material adverse effect with respect to Chinook) and (2) in the case of any of (j), (k) or (l) above, to the extent that any such change, event, condition, development, circumstance, state of facts or occurrence results from (i) any action taken (or the failure to take any action) by or at the direction of Chinook or its subsidiaries constituting fraud or material violation of applicable law or (ii) any willful and material failure on the part of Chinook or its subsidiaries to comply with the approved clinical protocol for the development of any specified product candidate (in which case such change, event, condition, development, circumstance, state of facts or occurrence may be taken into account in determining whether there has been a material adverse effect with respect to Chinook).

For purposes of the description of the Merger Agreement, a “material adverse effect with respect to Novartis” means any change, effect, event, fact, development or occurrence that prevents or materially impairs or delays Novartis or Merger Sub from consummating the Merger and the other transactions contemplated by the Merger Agreement on a timely basis and in any event on or before the outside date.

Conduct of Business Pending the Merger

The Merger Agreement provides that, from the date of the Merger Agreement to the Effective Time, except as set forth in the confidential disclosure letter delivered in connection with the Merger Agreement, or as otherwise expressly permitted or required by the Merger Agreement, as required by applicable law or with the prior written consent of Novartis, we will conduct our businesses in the ordinary course of business consistent with past practice, and we will use commercially reasonable efforts to preserve intact our present business organization, material assets, properties, contracts and authorizations, present employees, and relationships and goodwill with suppliers, licensors, licensees, contractors, partners and others having material business dealings with us.

The Merger Agreement further provides that, from the date of the Merger Agreement to the Effective Time, except as set forth in the confidential disclosure letter delivered in connection with the Merger Agreement, or as otherwise expressly contemplated by the Merger Agreement or required by applicable law or with the prior written consent of Novartis, we will not:

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No Solicitation; Alternative Proposals

Under the terms of the Merger Agreement, subject to certain exceptions described below, Chinook has agreed that it will not, and will cause each of directors, officers, employees, investment bankers, attorneys and other advisors or representatives (collectively, “representatives”) not to, directly or indirectly:

For purposes of the Merger Agreement:

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We have also agreed that we will, and will cause each of our affiliates to, and will instruct and use our reasonable best efforts to cause our and their respective representatives to, immediately:

The Merger Agreement provides that we will not, and will cause each of our representatives not to, release any person from, or waive, amend or modify any provision of, or grant permission under or fail to enforce any standstill provision in any agreement to which Chinook is a party; provided that, if the Board determines in good faith, after consultation with outside counsel, that the failure to take such action would be inconsistent with its fiduciary duties under applicable Law, Chinook may waive any such standstill provision solely to the extent necessary to permit the applicable person (if such person has not been solicited in breach of the foregoing covenants) to make, on a confidential basis to the Board, a takeover proposal, conditioned upon such person agreeing that Chinook shall not be prohibited from providing any information to Novartis (including information regarding any takeover proposal).

Notwithstanding these restrictions or anything to the contrary in any other provision of the Merger Agreement, if at any time prior to the Effective Time, we or any of our affiliates or representatives receive a bona fide, written takeover proposal that was first made after the date of the Merger Agreement and did not result from a breach of the Merger Agreement, then, in the event that the Board determines, in good faith, after consultation with its outside counsel and financial advisor, that such takeover proposal either is a superior proposal or would reasonably be expected to lead to a superior proposal and (y) the failure to take any of the actions below would be inconsistent with the Board’s fiduciary duties under applicable law (a “qualifying company takeover proposal”), Chinook may:

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Under the Merger Agreement, we must notify Novartis within 24 hours of making any determination that a takeover proposal is a qualifying company takeover proposal or taking any action described in three bullet points above.

During the period from the date of the Merger Agreement to the Effective Time, we are also required to as promptly as reasonably practicable and in any event no later than one business day after our receipt thereof:

Change in Company Recommendation

As described in “The Merger (Proposal 1)—Reasons for the Recommendation of our Board” beginning on page 39, and subject to the provisions described below, our Board has unanimously recommended that our stockholders vote “FOR” the proposal to adopt the Merger Agreement. We refer in this proxy statement to the following recommendation as the “company recommendation”: our Board (i) determining that the Merger Agreement, the CVR Agreement and the transactions contemplated thereby are fair to, and in the best interests of, Chinook and its stockholders, (ii) approving and declaring advisable the Merger Agreement and the transactions contemplated thereby, in each case on the terms and subject to the conditions set forth in the Merger Agreement, (iii) authorizing and approving the execution, delivery and performance by Chinook of the Merger Agreement and the consummation by Chinook of the transactions contemplated by the Merger Agreement, and (iv) recommending that the holders of shares of Chinook common stock adopt the Merger Agreement and directing that the Merger Agreement be submitted to Chinook’s stockholders at the Special Meeting for adoption.

The Merger Agreement provides that, except as described below, our Board or any committee thereof may not:

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Prior to obtaining stockholder approval of the adoption of the Merger Agreement, our Board or any committee thereof may make an adverse recommendation change under the following circumstances:

provided, however, that our Board will not take any action set forth in the bullet points immediately above unless, prior to taking such action:

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provided, further, that any purported termination of the Merger Agreement pursuant to this sentence will be void and of no force and effect unless such termination is made in accordance with the Merger Agreement and we pay to Novartis the termination fee of $112.0 million prior to or concurrently with such termination.

Notwithstanding the foregoing, nothing in the Merger Agreement shall prohibit Chinook from (i) taking and disclosing tour stockholders a position contemplated by Rule 14d-9(f) or Rule 14e-2(a) promulgated under the Exchange Act, in each case after commencement of a tender offer (within the meaning of Rule 14d-2 promulgated under the Exchange Act), including making any customary “stop-look-and-listen” communication to the stockholders of the Company pending disclosure of its position thereunder; provided that such communication does not contain or reflect an adverse recommendation change, or (ii) making any disclosure to our stockholders if our Board determines, in good faith, after consultation with outside counsel, that the failure to take such action would be inconsistent with its fiduciary duties or violates applicable law; provided that any adverse recommendation change will be subject to the terms and conditions of the Merger Agreement.

Efforts to Obtain Regulatory Approvals

Under the Merger Agreement, each party is required to use its reasonable best efforts to promptly take, or cause to be taken, all actions and to do, or cause to be done, and to assist and cooperate with the other parties in doing, all things necessary, proper or advisable to consummate and make effective, as promptly as practicable and in any event prior to the outside date, the Merger and the other transactions contemplated by the Merger Agreement, including:

In furtherance of the foregoing, Novartis and Chinook agreed that they will, in consultation and cooperation with the other, (i) file with the Federal Trade Commission (“FTC”) and Department of Justice (“DOJ”) the notification and report form required under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as

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amended (the “HSR Act”) for the Merger or any of the other transactions contemplated by the Merger Agreement as promptly as practicable (but in no event later than fifteen business days after the date of the Merger Agreement) and (ii) determine whether, and promptly prepare and make, any other filings or notifications or other consents required to be made with, or obtained from, any other governmental entities in connection with the Merger and the other transactions.

In addition, each of Novartis and Chinook have agreed that they will:

The parties agree not to extend, directly or indirectly, any waiting period under the HSR Act or any foreign antitrust law by more than 30 days, or to any day subsequent to the date 30 days prior to the outside date, or enter into any agreement with a governmental entity to delay by more than 30 days, or any day subsequent to the outside date, or not to consummate the Merger or any of the other transactions contemplated by the Merger Agreement, except with the prior written consent of the other party. Novartis shall, following consultation with Chinook, determine the strategy to obtain and lead the effort to obtain and secure the expiration or termination of any applicable waiting periods under the HSR Act or any foreign antitrust law and obtain any clearance or approval required to be obtained from the FTC, the DOJ, any state attorney general, any foreign competition

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authority or any other governmental entity in connection with the Merger and the other transactions contemplated by the Merger Agreement.

In furtherance of the foregoing, Novartis and Merger Sub agree to take promptly any and all steps necessary to avoid, eliminate or resolve each and every impediment and obtain all clearances, consents, approvals and waivers under the HSR Act or any foreign antitrust law that may be required by any governmental entity, so as to enable the parties to close the Merger and the other transactions contemplated by the Merger Agreement as soon as practicable (and in any event by or before the outside date). Notwithstanding the foregoing sentence or any other provision of the Merger Agreement, Novartis and Merger Sub are not required to take any action with respect to its or their assets, interests or businesses, or the assets, interests or businesses of Chinook or any of its subsidiaries, including:

Novartis has agreed not to acquire or agree to acquire any rights, business, person or division thereof (by way of license, Merger, consolidation, share exchange, investment, other business combination, asset, stock or equity purchase, or otherwise) or enter into or agree to enter into any joint venture, collaboration, or other similar arrangement, in each case that would reasonably be expected to prevent, materially delay or materially impair the ability of Novartis to obtain the approval of any governmental entity under any antitrust laws or the expiration or termination of any applicable waiting period with respect to the Merger prior to the outside date.

Chinook Stockholders’ Meeting

Under the Merger Agreement, we agreed to take all necessary actions in accordance with applicable law, our certificate of incorporation and our bylaws and the rules and regulations of The Nasdaq Stock Market, to duly call, give notice of, convene and hold a meeting of our stockholders for the purpose of obtaining stockholder approval of the proposal to adopt the Merger Agreement.

We may, after consultation with Novartis, adjourn, recess or postpone the Special Meeting only (i) to the extent required by applicable law to ensure that any required supplement or amendment to the proxy statement is provided to our stockholders within a reasonable amount of time in advance of the Special Meeting, (ii) to the extent required by a court of competent jurisdiction in connection with any litigation or proceedings or (iii) if, as of the time for which the Special Meeting is originally scheduled, there are insufficient shares of Chinook common stock represented (either in person or by proxy) to constitute a quorum necessary to conduct the business of our Special Meeting, in each case for the minimum duration necessary to remedy the circumstances giving rise to such adjournment, recess or postponement (and in any event, unless otherwise required by applicable law or a court of competent jurisdiction, not beyond the earlier of (A) the date that is 30 days after the date that the Special Meeting was originally scheduled (or, if applicable, 30 days after the newly scheduled date for any such originally scheduled stockholders meeting that is adjourned, recessed or postponed in accordance with the Merger Agreement), and (B) three business days prior to the outside date).

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Employee Matters

The Merger Agreement provides for the following treatment with respect to those employees of Chinook who continue to be employed by the Surviving Corporation or one of its subsidiaries after the Effective Time, whom we refer to as the “continuing employees”:

Under the Merger Agreement, Novartis has agreed to cause the Surviving Corporation to assume the obligations with respect to all rights to indemnification, advancement of expenses and exculpation from liabilities, for acts or omissions occurring at or prior to the Effective Time existing in favor of our current or former directors or officers as provided in our certificate of incorporation, our bylaws or any indemnification agreement between such indemnified person and us, without further action, as of the Effective Time. This obligation will survive the Merger, will continue in full force and effect in accordance with their terms, will not be impaired by any modification of such terms in any amendment or restatement of our certificate of incorporation or bylaws following the Effective Time and for a period of six years following the date of the Merger Agreement, may not be amended, repealed or otherwise modified in any manner that would adversely affect any rights of such current or former directors or officers.

Novartis has also agreed that for six years after the Effective Time, it will (and will cause the Surviving Corporation to) indemnify, defend and hold harmless, to the fullest extent permitted under applicable Law (and shall advance expenses as incurred to the fullest extent permitted under applicable Law, provided our current or former director or officer to whom expenses are advanced provides an undertaking to repay such advances if a court of competent jurisdiction determines in a final, nonappealable judgment that such person is not entitled to be indemnified hereunder), each such person’s against any costs or expenses (including reasonable attorneys’

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fees), judgments, settlements, fines, losses, claims, damages or liabilities (whether civil, criminal, administrative, investigative or other), arising out of or pertaining to matters existing or occurring at or prior to the Effective Time, including the Merger and the other transaction contemplated by the Merger Agreement.

Chinook has agreed to use its commercially reasonable efforts to obtain, at or prior to the Effective Time, a prepaid (or “tail”) directors’ and officers’ liability insurance policy in respect of acts or omissions occurring at or prior to the Effective Time, covering each person currently covered by our directors’ and officers’ liability insurance policies, with coverage for six years following the Effective Time, on terms with respect to such coverage and amounts no less favorable to the insureds than those of such policy in effect on the date of the Merger Agreement, up to coverage for an annual premium that does not exceed 300% of the most recent annual premium paid by us for such insurance for our current fiscal year.

In the event the Surviving Corporation (i) consolidates with or merges into any other person and is not the continuing or Surviving Corporation or entity of such consolidation or Merger or (ii) transfers all or substantially all of its properties and assets to any person, or Novartis dissolves the Surviving Corporation, then, and in each such case, Novartis or the Surviving Corporation shall cause proper provision to be made so that the applicable successors and assigns or transferees expressly assume the foregoing obligations.

Other Covenants and Agreements

The Merger Agreement also contains additional covenants, including, among others, covenants relating to the coordination with respect to stockholder litigation, filing of this proxy statement, access to information, obtaining required consents and regulatory approvals, making necessary notifications and filings, public announcements relating to the Merger, the CVR Agreement and tax matters.

Conditions to Completion of the Merger

Each party’s obligation to effect the Merger is subject to the satisfaction (or, to the extent permitted by applicable law, waiver by the parties entitled thereto) on or prior to the closing date of the following conditions:

The obligations of Novartis and Merger Sub to effect the Merger are subject to the satisfaction (or, to the extent permitted by law, waiver by Novartis and Merger Sub) on or prior to the closing date of the following additional conditions:

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The obligation of Chinook to effect the Merger is subject to the satisfaction (or, to the extent permitted by law, waiver by Chinook) on or prior to the closing date of the following additional conditions:

Termination

In general, the Merger Agreement may be terminated at any time prior to the Effective Time, whether before or after approval of the proposal to adopt the Merger Agreement by our stockholders (except as otherwise expressly noted), in the following ways:

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Fees and Expenses

Except as otherwise provided in the Merger Agreement (including the termination fees discussed below), all fees and expenses incurred in connection with the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement are to be paid by the party incurring such fees or expenses, whether or not the Merger is consummated.

Termination Fees

The Merger Agreement provides that Chinook will pay Novartis a termination fee of $112.0 million if:

The Merger Agreement provides that Novartis will pay Chinook a reverse termination fee of $192.0 million if either Novartis or Chinook:

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In no event will either Chinook or Novartis be required to pay its respective termination fee more than once.

In the event that Chinook pays a termination fee, it will be deemed to be liquidated damages and constitute the sole and exclusive remedy of Novartis and Merger Sub against Chinook and its current, former or future stockholders and representatives for any loss suffered as a result of the failure of the Merger or the other transactions contemplated by the Merger Agreement to be consummated (so long as any termination of the Merger Agreement by Chinook was in accordance with the applicable provision of the Merger Agreement); provided that nothing contained in the Merger Agreement will relieve any party thereto from liability for fraud or any willful breach of the Merger Agreement.

In the event that Novartis pays a reverse termination fee, it will be deemed to be liquidated damages and constitute the sole and exclusive remedy of Chinook against Novartis and Merger Sub and their current, former or future stockholders and representatives for any loss suffered as a result of the failure of the Merger or the other transactions contemplated by the Merger Agreement to be consummated (so long as any termination of the Merger Agreement by Novartis was in accordance with the applicable provision of the Merger Agreement); provided that nothing contained in the Merger Agreement will relieve any party thereto from liability for fraud or any willful breach of the Merger Agreement.

Amendment; Extensions and Waivers

The Merger Agreement may be amended by the parties thereto at any time prior to the Effective Time. At any time prior to the Effective Time, the parties thereto may (i) extend the time for the performance of any of the obligations or other acts of the other parties thereto, (ii) waive any inaccuracies in the representations and warranties contained in the Merger Agreement or in any document delivered pursuant to the Merger Agreement or (iii) waive compliance with any of the agreements or conditions contained in the Merger Agreement. The Merger Agreement may not be amended or supplemented after the Effective Time.

CVR Agreement

At or prior to the Effective Time, Novartis will execute and deliver, and will cause the Rights Agent to execute and deliver, the CVR Agreement. Novartis and Chinook will cooperate, including by making changes to the form of CVR Agreement, as necessary to ensure that the CVRs are not subject to registration under the Securities Act, the Exchange Act or any applicable state securities or “blue sky” laws.

Governing Law

The Merger Agreement is governed by, and construed in accordance with, the laws of the State of Delaware (regardless of the laws that might otherwise govern under applicable principles of conflicts of laws thereof).

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CONTINGENT VALUE RIGHTS AGREEMENT

The following is a summary of the material provisions of the CVR Agreement, a copy of which is attached to this proxy statement as Exhibit A to the Merger Agreement attached as Annex A and which is incorporated by reference into this proxy statement. This summary does not purport to be complete and may not contain all of the information about the CVR Agreement that is important to you. We encourage you to read carefully the CVR Agreement in its entirety, as the rights and obligations of the parties thereto are governed by the express terms of the CVR Agreement and not by this summary or any other information contained in this proxy statement.

Explanatory Note Regarding the Form of CVR Agreement

The CVR Agreement will be executed by Novartis and the Rights Agent at the closing of the Merger. The descriptions of the form of CVR Agreement in this summary and elsewhere in this proxy statement are not complete and are qualified in their entirety by reference to the form of CVR Agreement, a copy of which is attached to this proxy statement as Exhibit A to the Merger Agreement attached as Annex A and incorporated into this proxy statement by reference. We encourage you to read the CVR Agreement carefully and in its entirety because this summary may not contain all the information about the CVR Agreement that is important to you. The rights and obligations of the parties are governed by the express terms of the form of CVR Agreement and not by this summary or any other information contained in this proxy statement.

Contingent Value Rights

Each CVR represents the right of its holders to receive contingent cash payments pursuant to the CVR Agreement if the conditions to those payments are satisfied. The initial holders will be the (i) holders of shares of Chinook common stock converted into the right to receive the Total Per Share Consideration pursuant to the Merger Agreement, (ii) former holders of Chinook equity awards whose awards converted into the right to receive the Total Per Share Consideration pursuant to the Merger Agreement and (iii) former holders of our warrants whose warrants converted into the right to receive the Total Per Share Consideration pursuant to the Merger Agreement.

The CVRs will not have voting or dividend rights, and interest will not accrue on any amounts payable on the CVRs to any holder. The CVRs will not represent any equity or ownership interest in Novartis, Chinook, the Surviving Corporation or any of their respective affiliates.

Milestone Payments

While no guarantee can be given that any proceeds will be received, each CVR represents the right to receive the following contingent cash payments:

Non-Transferability

The CVRs may not be sold, assigned, transferred, pledged, encumbered or in any other manner transferred or disposed of other than under the following specified circumstances:

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Every request to transfer CVRs must be in writing in accordance with the CVR Agreement.

Evidence of CVR; Registration

The CVRs will not be evidenced by a certificate or other instruments. The Rights Agent will keep an up-to-date register (the “CVR Register”) for the purpose of identifying the holders of the CVRs and registering CVRs and permitted transfers thereof. The CVR Register will initially show one position for Cede & Co. representing all shares of Chinook common stock held by DTC on behalf of street name holders of the shares of Chinook common stock held by such holders as of immediately prior to the Effective Time. In the case of holders of stock options, RSUs or PSUs (collectively, “Chinook Equity Awards”) or warrants, the CVRs will be registered in the names and addresses of such holder of Chinook Equity Awards or warrants and in a denomination equal to the number of shares of Chinook common stock underlying the outstanding Chinook Equity Awards or warrants held by such holder of Chinook Equity Awards or warrants immediately prior to the Effective Time. No transfer of a CVR will be valid, even if permitted, until it is registered in the CVR Register in accordance with the CVR Agreement.

A holder may make a written request to the Rights Agent to change such holder’s address of record in the CVR Register. The written request must be duly executed by the holder. Upon receipt of such written notice, the Rights Agent will, subject to its reasonable determination that the written notice is in proper form, promptly record the change of address in the CVR Register.

Payment Procedures

If a Milestone is attained during the applicable Milestone Period, then, in each case, as promptly as practicable (and in any event within 30 business days), Novartis will deliver or cause to be delivered to the Rights Agent (i) a written notice (a “Milestone Achievement Notice”) certifying the date of the satisfaction of the applicable Milestone and that the holders are entitled to receive $2.00 per CVR, (ii) any letter of instruction reasonably required by the Rights Agent and (iii) cash, by wire transfer of immediately available funds to an account designated by the Rights Agent, equal to the aggregate cash owed to all holders of CVRs upon such achievement, other than holders of CVRs in respect of Chinook Equity Awards, who shall be through the payroll system of Novartis or its subsidiaries or a third-party payroll provider. After receipt of the wire transfer, the Rights Agent will promptly (and in any event, within 30 business days) pay the CVR holders of record:

Each of Novartis and the Rights Agent may require payment, from any holder of CVR and any transferee of such holder, of a sum sufficient to cover any stamp or other tax or other charge of any nature whatsoever that is

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imposed by a governmental authority or taxing authority in connection with any such registration or transfer. Each of Novartis and the Rights Agent will have no duty or obligation to take any action under any section of the CVR Agreement that requires the payment by a holder or a transferee of a CVR of applicable taxes or charges unless and until each of Novartis and the Rights Agent is satisfied that all such taxes or charges have been paid by such holder or such transferee.

Tax Withholding

Novartis and the Rights Agent and each of their respective affiliates will be entitled to deduct and withhold from amounts otherwise payable pursuant to the CVR Agreement such amounts as may be required to be deducted and withheld under applicable law. Prior to making any such deduction or withholding, other than ordinary course payroll withholding and reporting, if applicable, the Rights Agent will, to the extent practicable, provide notice to the relevant holder of such potential withholding and, if applicable, a reasonable opportunity for the stockholder to provide any IRS Form W-8, or any other appropriate forms or information in order to avoid or reduce such deduction and withholding, and the time period for payment of a Milestone Payment by the Rights Agent to such holder will be extended by a period equal to any delay caused by such holder providing such forms. Any amounts deducted or withheld and remitted to the relevant governmental authorities will be treated for all purposes under the CVR Agreement and the Merger Agreement as having been paid to the person to whom such amounts would otherwise have been paid.

Undistributed Payments; Imputed Interest

Any portion of any Milestone Payment that remains undistributed to the holders six months after the date of the achievement of the applicable Milestone will be delivered by the Rights Agent to Novartis or its designated affiliate, upon demand, and any holder will thereafter look only to Novartis for payment of such Milestone Payment, without interest, but such holder will have no greater rights against Novartis than those accorded to general unsecured creditors of Novartis under applicable law.

Neither Novartis nor the Rights Agent will be liable to any person in respect of any Milestone Payment delivered to a public official in compliance with any applicable state, federal or other abandoned property, escheat or similar law. Novartis will indemnify and hold harmless the Rights Agent with respect to any liability, penalty, cost or expense the Rights Agent may incur or be subject to in connection with transferring such property to Novartis.

Except to the extent any portion of the Milestone Payment is required to be treated as imputed interest and except as otherwise required pursuant to applicable law, the parties to the CVR Agreement intend to treat the Milestone Payments payable with respect to CVRs issued in exchange for shares of Chinook common stock for all tax purposes as additional consideration for such shares, pursuant to the Merger Agreement.

Enforcement of Rights of Holders

Any actions seeking the enforcement of the rights of holders under the CVR Agreement may only be brought either by the Rights Agent or the holders of at least 45% of the outstanding CVRs as set forth in the CVR Register (the “Acting Holders”).

Rights Agent

The Rights Agent will be Computershare Trust Company, N.A., as the transfer agent of the Company or, at the election of Novartis, such other person selected by Novartis and reasonably acceptable to Chinook. Novartis will (i) pay the fees and expenses of the Rights Agent in connection with the CVR Agreement, (ii) reimburse the Rights Agent for (x) all taxes other than (A) withholding taxes owed by the holders and (B) taxes imposed on or measured by the Rights Agent’s net income and franchise or similar taxes imposed on it (in lieu of net income taxes) and (y) governmental charges, reasonable and documented out-of-pocket expenses and other charges of any kind and nature incurred by the Rights Agent in the execution of the CVR Agreement (other than taxes).

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The Rights Agent may resign at any time by notifying Novartis in writing at least 60 days before the resignation takes effect and Novartis may remove the Rights Agent at any time by notifying the Rights Agent in writing at least 30 days before the removal takes effect, by specifying a date when such removal will take effect.

Covenants by Novartis

Among other things, the CVR Agreement provides for certain covenants made by Novartis.

List of Holders

Novartis will furnish to the Rights Agent, in no event later than 30 days following the Effective Time, the names and addresses of the holders in such form as Novartis receives from the Company’s transfer agent.

Payment of Milestone Payment

Novartis will cause to be deposited with the Rights Agent, on or prior to the date of payment in respect of achievement of any Milestone, the amount to be made to the holders in accordance with the terms of the CVR Agreement.

No Obligation

The form of CVR Agreement provides that Novartis and its affiliates are not required to undertake any level of efforts, or employ any level of resources, to achieve either of the Milestones prior to the end of the respective Milestone Period. However, the form of CVR Agreement provides that, without limiting the foregoing, neither Novartis nor any of its affiliates will take any action or fail to take any action in bad faith with the primary purpose of avoiding the achievement of either Milestone or the payment of either Milestone Payment.

Assignment Transactions

Novartis will not, and will cause its affiliates, including the Surviving Corporation, not to, sell, assign, transfer or exclusively license all or substantially all of the rights, to research, develop, manufacture, commercialize and otherwise exploit atrasentan for Indication 1 and/or Indication 2 to a third party if any Milestone Payments remain unpaid unless:

If such third party is a significant pharmaceutical company, upon consummation of such sale, assignment, transfer or exclusive license and execution by such third party of such assumption agreement, and notice thereof to the Rights Agent and the holders, neither Novartis, nor any of its affiliates (including the Surviving Corporation), will have any further liability or obligation with respect to the CVR Agreement. Novartis will

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provide the Rights Agent and the holders with prompt written notice of any such sale or assignment. The foregoing restrictions set forth in the CVR Agreement will not apply to sales of atrasentan made by Novartis or its subsidiaries or affiliates, any sale, assignment, transfer or exclusive license of all or substantially all of the rights to atrasentan in any country except for the United States, or ordinary course non-exclusive licensing arrangements between Novartis and its affiliates, on the one hand, and third-party licensees, distributors and contract manufacturers on the other hand, entered into in the ordinary course of business for purposes of developing, manufacturing, distributing or selling atrasentan.

Other Covenants

Novartis will not, and will cause its subsidiaries not to, enter into any agreement with any third party that is, or otherwise take any actions or inactions, in conflict with the CVR Agreement in any material respect or materially adversely affect the performance of its obligations under the CVR Agreement.

Amendments

Amendments without the Consent of Holders

Without the consent of any holders or the Rights Agent, Novartis, at any time and from time to time, may enter into one or more amendments to the CVR Agreement, for any of the following purposes:

Promptly after the execution by Novartis of any amendment pursuant to the conditions bulleted above, Novartis will transmit notice thereof through the facilities of DTC in accordance with DTC’s procedures and/or by first class mail to the holders at their addresses as they appear on the CVR Register, setting forth such amendment.

Amendments with the Consent of Holders

With the prior consent of the majority of holders of CVRs, whether evidenced in writing or taken at a meeting of the holders, Novartis and the Rights Agent may enter into one or more amendments hereto for the purpose of

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adding, eliminating or changing any provisions of the CVR Agreement, even if such addition, elimination or change is materially adverse to the interest of the holders. Promptly after the execution by Novartis and the Rights Agent of any such amendment, Novartis will transmit notice thereof through the facilities of DTC in accordance with DTC’s procedures and/or by first class mail to the holders at their addresses as they appear on the CVR Register, setting forth such amendment.

Termination

The CVR Agreement will be terminated upon the earlier to occur of (a) the payment by the Rights Agent to each holder of both Milestone Payments required to be paid under the terms of the CVR Agreement, (b) the delivery of a written notice of termination duly executed by Novartis and the majority of holders of CVRs and (c) the expiration of both Milestone Periods. The termination of the CVR Agreement will not affect or limit the right to receive the Milestone Payments to the extent earned prior to termination.

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ADVISORY VOTE ON NAMED EXECUTIVE OFFICER MERGER-RELATED COMPENSATION

(PROPOSAL 2)

As required by Section 14A of the Exchange Act and the applicable SEC rules issued thereunder, we are providing our stockholders with a separate advisory (non-binding) vote to approve certain compensation that may be paid or become payable to our named executive officers in connection with the Merger, as described in the table entitled “Quantification of Payments and Benefits to Chinook Named Executive Officers” under “The Merger (Proposal 1)—Interests of Chinook’s Directors and Executive Officers in the Merger,” including the footnotes to the table and related narrative discussion. Accordingly, we are requesting that our stockholders approve the following resolution on an advisory (non-binding) basis:

“RESOLVED, that the compensation that may be paid or become payable to Chinook’s named executive officers in connection with the Merger, and the agreements or understandings pursuant to which such compensation may be paid or become payable, in each case as disclosed pursuant to Item 402(t) of Regulation S-K in the section entitled “The Merger (Proposal 1)—Interests of Chinook’s Directors and Executive Officers in the Merger—Quantification of Payments and Benefits to Chinook Named Executive Officers,” is hereby APPROVED.”

The vote on the named executive officer Merger-related compensation proposal is a vote separate and apart from the vote on the proposal to adopt the Merger Agreement. Accordingly, you may vote to adopt the Merger Agreement and vote not to approve the named executive officer Merger-related compensation proposal and vice versa. Because the vote on the named executive officer Merger-related compensation proposal is advisory only, it will not be binding on either Chinook or Novartis. Accordingly, if the Merger Agreement is adopted and the Merger is completed, the Merger-related compensation will be payable, subject only to the conditions applicable thereto under the applicable compensation agreements and arrangements, regardless of the outcome of the non-binding, advisory vote of our stockholders.

The above resolution approving the Merger-related compensation of our named executive officers on an advisory basis requires the affirmative vote of a majority of the shares of our common stock present in person or represented by proxy at the Special Meeting and entitled to vote on the proposal and are voted for or against the proposal.

Our Board unanimously recommends that the stockholders of Chinook vote “FOR” the named executive officer Merger-related compensation proposal.

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AUTHORITY TO ADJOURN THE SPECIAL MEETING (PROPOSAL 3)

Our stockholders may be asked to vote on a proposal to adjourn the Special Meeting, if necessary or appropriate, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to approve the proposal to adopt the Merger Agreement.

We do not anticipate calling a vote on this proposal if the proposal to adopt the Merger Agreement is approved by at least a majority of the outstanding shares of our common stock as of the Record Date.

The vote on the adjournment proposal is a vote separate and apart from the vote on the proposal to adopt the Merger Agreement. Accordingly, you may vote to approve the proposal to adopt the Merger Agreement and vote not to approve the adjournment proposal and vice versa.

Approval of the adjournment proposal requires the affirmative vote of a majority of the shares of our common stock present in person or represented by proxy at the Special Meeting and entitled to vote on the proposal and are voted on the proposal.

Our Board unanimously recommends that the stockholders of Chinook vote “FOR” the adjournment proposal, if a vote on such proposal is called.

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SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth certain information regarding the ownership of the Company’s common stock as of July 3, 2023, by: (i) each of the Company’s directors and named executive officers; (ii) all executive officers and directors of the Company as a group; and (iii) all those known by the Company to be beneficial owners of more than five percent of its common stock.

Beneficial ownership is determined according to the rules of the SEC and generally means that a person has beneficial ownership of a security if he, she or it possesses sole or shared voting or investment power of that security, including options and warrants that are currently exercisable or exercisable within 60 days of July 3, 2023. Except as indicated by the footnotes below, we believe, based on the information furnished to us, that the persons and entities named in the table below have sole voting and investment power with respect to all shares of common stock shown that they beneficially own.

Unless otherwise indicated, the address of each beneficial owner listed in the table below is c/o Chinook Therapeutics, Inc., 400 Fairview Ave., N., Suite 900, Seattle WA 98109.

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