Mirati Therapeutics (MRTX) PREM14APreliminary proxy related to merger

You are cordially invited to attend a special meeting of stockholders (which, together with any adjournments or postponements thereof, we refer to as the “Special Meeting”) of Mirati Therapeutics, Inc., a Delaware corporation (which we refer to as “Mirati,” “we,” “us” or “our”) to be held virtually via live webcast on [•], 2023, at [•], Eastern time (unless the Special Meeting is adjourned or postponed). You may attend the Special Meeting virtually via the Internet at [•], where you will also be able to vote and submit your questions. Please note that you will not be able to attend the Special Meeting physically in person. For purposes of attendance at the Special Meeting, all references in the enclosed proxy statement to “attendance at the Special Meeting” or “present at the Special Meeting” mean virtually present at the Special Meeting. Formal notice of the Special Meeting, a proxy statement, and a proxy card accompany this letter.

At the Special Meeting, you will be asked to consider and vote on a proposal to adopt the Agreement and Plan of Merger (which we refer to, as it may be amended from time to time, as the “Merger Agreement”), dated October 8, 2023, by and among Mirati, Bristol-Myers Squibb Company, a Delaware corporation (which we refer to as “BMS” or “Parent”), and Vineyard Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of Parent (which we refer to as “Merger Sub”), including the form of contingent value rights agreement to be entered into at or immediately prior to the effective time of the Merger by Parent and a rights agent reasonably acceptable to Mirati (which we refer to as the “CVR Agreement”) (we refer to such proposal as the “Merger Proposal”). At the Special Meeting, you will also be asked to consider and vote on a non-binding, advisory proposal to approve compensation that may be paid or become payable by Mirati to its named executive officers in connection with the Merger (which we refer to as the “Compensation Proposal”) and a proposal to adjourn the Special Meeting, if necessary or appropriate, to solicit additional proxies if there are insufficient votes to adopt the Merger Agreement at the time of the Special Meeting (which we refer to as the “Adjournment Proposal”).

Pursuant to the terms of the Merger Agreement, Merger Sub will merge with and into Mirati (which we refer to as the “Merger”), with Mirati surviving the Merger as a wholly owned subsidiary of Parent. If you are a Mirati stockholder and the Merger is completed, each of your Mirati shares of common stock, par value $0.001, (which we refer to as the “common stock”), will be converted into the right to receive (A) $58.00 in cash, without interest (which we refer to as the “Closing Consideration”) and (B) one contingent value right (which we refer to as a “CVR”), which shall represent the right to receive the Milestone Payment (which we define in the section of this proxy statement captioned “Form of Contingent Value Rights Agreement”), without interest and subject to the terms and conditions set forth in the CVR Agreement (we refer to the consideration contemplated by (A) and (B), together, and in each case subject to any applicable withholding of taxes, as the “Merger Consideration”) (unless you have properly exercised, and not subsequently withdrawn, your appraisal rights under Section 262 of the Delaware General Corporation Law (which we refer to as the “DGCL”)).

The enclosed proxy statement provides 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

Whether or not you plan to attend the Special Meeting virtually, please sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone by following the instructions on the enclosed proxy card. If you attend the Special Meeting and vote online during the meeting, your vote will revoke any proxy that you have previously submitted.

If you hold your shares of our common stock in “street name,” you should instruct your bank, broker or other nominee how to vote your shares of our common stock 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 Merger Proposal, without your instructions.

If you have any questions or need assistance voting your shares of our common stock, please contact our Proxy Solicitor:

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

The accompanying proxy statement is dated [•], 2023 and, together with the enclosed form of proxy card, is first being mailed on or about [•], 2023.

WHETHER OR NOT YOU PLAN TO ATTEND THE SPECIAL MEETING VIRTUALLY, WE ENCOURAGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) BY SIGNING AND DATING THE ENCLOSED PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED; (2) THROUGH THE INTERNET; OR (3) BY TELEPHONE. 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 of our common stock in “street name,” you should instruct your bank, broker or other nominee how to vote your shares of our common stock 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 Merger Proposal, without your instructions.

If you are a stockholder of record, voting online during the Special Meeting will revoke any proxy that you previously submitted. If you hold your shares of our common stock through a bank, broker or other nominee, you must obtain a “legal proxy” in order to vote online at the Special Meeting.

If you fail to (1) return your signed proxy card; (2) grant your proxy electronically over the Internet or by telephone; or (3) attend the Special Meeting and vote online during the meeting, your shares of our common stock 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 Merger Proposal, but will have no effect on the Compensation Proposal or the Adjournment Proposal.

We encourage you to read the accompanying proxy statement and its annexes, including all documents incorporated by reference into the accompanying proxy statement, carefully and in their entirety. If you have any questions concerning the Merger, the Special Meeting or this proxy statement, would like additional copies of this proxy statement or need help voting your shares of our common stock, please contact our Proxy Solicitor:

The following questions and answers address some commonly asked questions regarding the Merger, the Merger Agreement (including the form of CVR Agreement, which is an exhibit to the Merger Agreement) and the Special Meeting. These questions and answers may not address all questions that are important to you. We encourage you to read carefully the more detailed information contained elsewhere in this proxy statement and the full text of the annexes to this proxy statement and the documents we refer to in this proxy statement because the information in this section does not provide all the information that might be important to you with respect to the Merger, the Merger Agreement and the Special Meeting. You may obtain the information incorporated by reference in this proxy statement without charge by following the instructions in the section of this proxy statement captioned “Where You Can Find More Information.”

All statements in this proxy statement and any document referred to or incorporated by reference in this proxy statement, other than statements of historical fact, are statements that could be deemed “forward-looking statements”, regarding, among other things, the Merger, potential contingent consideration, and the development and commercialization of certain biological compounds, including the therapeutic and commercial potential of KRAZATI® (adagrasib), sitravatinib (TAM receptor inhibitor), MRTX1719 (MTA-cooperative PRMT5 inhibitor), MRTX0902 (SOS1 inhibitor), MRTX1133 (selective KRASG12D inhibitor), and Mirati’s other technologies and products in development. These statements may be identified by the fact they use words such as “should,” “could,” “expect,” “anticipate,” “estimate,” “target,” “may,” “project,” “guidance,” “intend,” “plan,” “believe,” “will” and other words and terms of similar meaning and expression in connection with any discussion of future operating or financial performance, although not all forward-looking statements contain such terms. All statements that are not statements of historical facts are, or may be deemed to be, forward-looking statements. These statements are only predictions, and such forward-looking statements are based on current expectations and involve inherent risks and uncertainties, including factors that could delay, divert or change any of them, and could cause actual outcomes and results to differ materially from current expectations. No forward-looking statement can be guaranteed. Actual results may differ materially from current expectations because of numerous risks and uncertainties including with respect to (i) the approval of Mirati’s stockholders of the Merger Proposal and the other proposals to be presented at the Special Meeting, which may be delayed or may not be obtained, (ii) whether the contingent consideration under the CVR will become payable, (iii) the risk that the expected benefits or synergies of the acquisition will not be realized, (iv) the risk that legal proceedings may be instituted related to the Merger Agreement, (v) any competing offers or acquisition proposals for Mirati, (vi) the possibility that various conditions to the consummation of the Merger may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the acquisition and (vii) unanticipated difficulties or expenditures relating to the proposed acquisition, the response of business partners and competitors to the announcement of the proposed Merger and/or potential difficulties in employee retention as a result of the announcement and pendency of the proposed Merger. In addition, the compounds described in any document referred to or incorporated by reference in this proxy statement are subject to all the risks inherent in the drug development process, and there can be no assurance that the development of these compounds will be commercially successful. Forward-looking statements in this proxy statement should be evaluated together with the many uncertainties that affect BMS’ business, particularly those identified in the cautionary factors discussion in BMS’ Annual Report on Form 10-K for the year ended December 31, 2022, and Mirati’s business, particularly those identified in the cautionary factors discussion in Mirati’s Annual Report on Form 10-K for the year ended December 31, 2022, as well as other documents that may be filed by BMS or Mirati from time to time with the SEC. Neither BMS nor Mirati undertakes any obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. The forward-looking statements made in this proxy statement relate only to events as of the date on which the statements are made.

We will hold the Special Meeting on [•], 2023, at [•], Eastern time (unless the Special Meeting is adjourned or postponed). You can virtually attend, and vote and submit your questions in the Special Meeting by accessing a virtual live website using the Internet at [•]. Please note that you will not be able to attend the Special Meeting physically in person. Instructions on how to attend and participate online are provided on the proxy card. We expect check-in to be available starting around [•], Eastern time, on the day of the Special Meeting, [•], and you should allow ample time for online check-in proceedings. We will have technicians standing by and ready to assist you with any technical difficulties you may have in accessing the virtual live webcast. If you encounter any difficulties accessing the virtual live webcast during the check-in or meeting time, please call the support team at [•].

At the Special Meeting, we will ask stockholders to vote to approve (1) the Merger Proposal, (2) the Compensation Proposal and (3) the Adjournment Proposal.

Only stockholders of record as of the Record Date are entitled to notice of the Special Meeting and to vote at the Special Meeting. As of the Record Date, there were [•] shares of our common stock outstanding and entitled to vote at the Special Meeting. A complete list of registered stockholders as of the close of business on the Record Date will be available for inspection during ordinary business hours by stockholders of record 10 days prior to the Special Meeting at our principal business offices at 3545 Cray Court, San Diego, California 92121 and during the entirety of the Special Meeting online at [•].

The stockholders of at least forty percent (40%) in voting power of the shares of our common stock issued and outstanding and entitled to vote thereat, present virtually at the Special Meeting or represented by proxy, will constitute a quorum at the Special Meeting. In the event that a quorum is not present at the Special Meeting, it is expected that the meeting will be adjourned to solicit additional proxies.

Each Mirati stockholder will be entitled to one vote for each share of our common stock that such stockholder owns at the close of business on the Record Date on each proposal to be acted upon at the Special Meeting. The affirmative vote of the stockholders of a majority of the outstanding shares of our common stock entitled to vote as of the close of business on the Record Date is required to approve the Merger Proposal. As of the Record Date, [•] votes constitute a majority of the outstanding shares of our common stock entitled to vote on the Merger Proposal. Shares deemed not in attendance at the Special Meeting (whether due to a record holder’s failure to vote or a “street name” holder’s failure to provide any voting instructions to such holder’s bank, broker or other nominee), abstentions and broker non-votes will have the same effect as a vote “AGAINST” the Merger Proposal. Approval of the Merger Proposal by our stockholders is a condition to the closing of the transactions contemplated by the Merger Agreement.

The approval of the Compensation Proposal, on an advisory, non-binding basis, requires the affirmative vote of a majority of shares of our common stock present or represented by proxy and entitled to vote thereon. Accordingly, shares deemed not in attendance at the Special Meeting (whether due to a record holder’s failure to vote or a “street name” holder’s failure to provide any voting instructions to such holder’s bank, broker or other nominee) and broker non-votes will have no effect on the outcome of the Compensation Proposal. Abstentions will have the same effect as a vote “AGAINST” the Compensation Proposal. The approval of the Compensation Proposal is advisory and non-binding and is not a condition to the completion of the Merger.

The approval of the Adjournment Proposal, if necessary or appropriate, requires the affirmative vote of a majority of shares of our common stock present or represented by proxy and entitled to vote thereon. Accordingly, shares deemed not in attendance at the Special Meeting (whether due to a record holder’s failure to

If you fail to (1) return your signed proxy card; (2) grant your proxy electronically over the Internet or by telephone; or (3) attend the Special Meeting and vote online during the meeting, your shares of our common stock 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 Merger Proposal, but will have no effect on the Compensation Proposal or the Adjournment Proposal.

Mirati does not expect any broker non-votes at the Special Meeting because the rules applicable to banks, brokers and other nominees only provide brokers with discretionary authority to vote on proposals that are considered routine, whereas each of the proposals to be presented at the Special Meeting is considered non-routine. As a result, no broker will be permitted to vote your shares of our common stock at the Special Meeting without receiving instructions. Failure to instruct your broker on how to vote your shares of our common stock will have the same effect as a vote “AGAINST” the Merger Proposal, but assuming a quorum is present at the Special Meeting, not have any effect on the Compensation Proposal or the Adjournment Proposal.

As of the Record Date, our directors and executive officers beneficially owned and were entitled to vote, in the aggregate, [•] shares of our common stock, representing approximately [•]% of the shares of our common stock outstanding on the Record Date.

We currently expect that our directors and executive officers will vote all of their respective shares of our common stock: (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

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

You must have the enclosed proxy card available, and follow the instructions on the proxy card, in order to grant a proxy electronically over the Internet or by telephone. Based on your proxy cards or Internet and telephone proxies, the proxy holders will vote your shares of our common stock according to your directions.

Even if you plan to attend the Special Meeting virtually, you are strongly encouraged to vote your shares of our common stock by proxy. If you are a record holder or if you obtain a “legal proxy” to vote your shares of our common stock that you beneficially own, you may still vote your shares of our common stock online at the

Voting instructions are included on your proxy card. All shares of our common stock represented by properly signed and dated proxies received in time for the Special Meeting will be voted at the Special Meeting in accordance with the instructions of the stockholder. Properly signed and dated proxies that do not contain voting instructions will be voted (1) “FOR” the Merger Proposal; (2) “FOR” the Compensation Proposal; and (3) “FOR” the Adjournment Proposal.

If your shares of our common stock 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 attending the Special Meeting and voting online with a “legal proxy” from your bank, broker or other nominee. If such a service is provided, you may vote over the Internet or telephone through your bank, broker or other nominee by following the instructions on the voting form provided by your bank, broker or other nominee. If you do not return your bank’s, broker’s or other nominee’s voting form, do not vote via the Internet or telephone through your bank, broker or other nominee, if possible, or do not attend the Special Meeting and vote online with a “legal proxy” from your bank, broker or other nominee, it will have the same effect as if you voted “AGAINST” the Merger Proposal but, assuming a quorum is present at the Special Meeting, will not have any effect on the Compensation Proposal or the Adjournment Proposal.

If you are a stockholder of record, you may change your vote or revoke your proxy at any time before it is voted at the Special Meeting by:

If you have submitted a proxy, your appearance at the Special Meeting virtually, in the absence of voting online during the Special Meeting or submitting an additional proxy or revocation, will not have the effect of revoking your prior proxy.

If you hold your shares of our common stock in “street name,” you should contact your bank, broker or other nominee for instructions regarding how to change your vote. You may also vote online at the Special Meeting if you obtain a “legal proxy” from your bank, broker or other nominee.

Any adjournment, postponement or other delay of the Special Meeting, including for the purpose of soliciting additional proxies, will allow stockholders who have already sent in their proxies to revoke them at any time prior to their use at the Special Meeting as adjourned, postponed or delayed.

The Board of Directors, after careful consideration, including considering various factors described in the section of this proxy statement captioned “The Merger — Recommendation of the Board of Directors and Reasons for the Merger,” has unanimously (1) determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are advisable and fair to, and in the best interest of, Mirati and its stockholders; (2) declared it advisable for Mirati to enter into the Merger Agreement; (3) approved the execution, delivery and performance by Mirati of the Merger Agreement and the consummation of the transactions contemplated thereby, including the Merger; (4) directed that the Merger Agreement be submitted to the Mirati stockholders for adoption; and (5) recommended that Mirati stockholders adopt the Merger Agreement.

The expense of soliciting proxies will be borne by Mirati. We have retained Innisfree M&A Incorporated, a proxy solicitation firm (which we refer to as the “Proxy Solicitor”), to solicit proxies in connection with the Special Meeting at a cost of approximately $40,000, plus a success fee of $20,000 and expenses. We will also indemnify the Proxy Solicitor against losses arising out of its provisions of these services on our behalf. In addition, we may reimburse banks, brokers and other nominees representing beneficial owners of shares of our common stock for their expenses in forwarding soliciting materials to such beneficial owners. Proxies may also be solicited by our directors, officers and employees, personally or by telephone, email, fax, over the Internet or other means of communication. No additional compensation will be paid for such services.

Assuming timely satisfaction of necessary closing conditions, including the approval by our stockholders of the Merger Proposal, we anticipate, but cannot guarantee, that the Merger will be consummated in the first half of 2024.

If the Merger is completed, stockholders who do not vote in favor of the adoption of the Merger Agreement and who properly demand appraisal of their shares of our common stock will be entitled to appraisal rights in connection with the Merger so long as they comply fully with Section 262. This means that stockholders are entitled to have their shares of our common stock appraised by the Delaware Court of Chancery and to receive in lieu of the Merger Consideration payment in cash of the amount determined by the Delaware Court of Chancery to be the “fair value” of their shares of our common stock, exclusive of any elements of value arising from the accomplishment or expectation of the Merger, together with interest to be paid on the amount determined to be fair value, if any, as determined by the court, so long as they comply fully with the procedures established by Section 262. Due to the complexity of the appraisal process, stockholders who wish to seek appraisal of their shares of our common stock are encouraged to seek the advice of legal counsel with respect to the exercise of appraisal rights.

Stockholders wishing to exercise the right to seek an appraisal of their shares of our common stock must do ALL of the following:

Your failure to follow exactly the procedures specified under the DGCL will result in the loss of your appraisal rights. The DGCL requirements for exercising appraisal rights are described in further detail in the section of this proxy statement captioned “The Merger — Appraisal Rights,” and Section 262, the relevant section of the DGCL regarding appraisal rights, may be accessed without subscription or cost at the following

At this time, we know of no other matters to be voted on at the Special Meeting. If any other matters properly come before the Special Meeting, your shares of our common stock will be voted in accordance with the discretion of the appointed proxy holders.

The proxy statement is available at https://ir.mirati.com/financials/sec-filings.

The SEC has adopted rules that permit companies and intermediaries, such as brokers, to satisfy the delivery requirements for proxy statements with respect to two or more stockholders sharing the same address by delivering a single proxy statement, as applicable, addressed to those stockholders. This process, which is commonly referred to as “householding,” potentially provides extra convenience for stockholders and cost savings for companies.

We will promptly deliver a separate copy of this proxy statement to any stockholder upon request submitted in writing to us at our principal offices at 3545 Cray Court, San Diego, California 92121 Attn: Investor Relations, or by email at ir@mirati.com.

If two or more stockholders sharing the same address are currently receiving multiple copies of this proxy statement and would like to receive only one copy for their household, the stockholders should contact their bank, broker or other nominee record holder, or contact us as instructed above.

If you have any questions concerning the Merger, the Special Meeting or this proxy statement, would like additional copies of this proxy statement or need help voting your shares of our common stock, please contact our Proxy Solicitor:

We are asking you to adopt the Merger Agreement pursuant to which Merger Sub will merge with and into Mirati, and Mirati will become a wholly owned subsidiary of Parent.

For a summary of and detailed information regarding this proposal, see the information about the Merger Agreement and the Merger throughout this proxy statement, including the information set forth in the sections of this proxy statement captioned “The Merger” and “The Merger Agreement.” This summary does not purport to be complete and may not contain all of the information about the Merger that is important to you. A copy of the Merger Agreement is attached to this proxy statement as Annex A. You are urged to read the Merger Agreement carefully in its entirety.

Under applicable law, we cannot complete the Merger without the affirmative vote of a majority of the outstanding shares of our common stock voting in favor of this Merger Proposal. If you abstain from voting, fail to cast your vote, online during the Special Meeting or by proxy, or fail to give voting instructions to your brokerage firm, bank, trust or other nominee, it will have the same effect as a vote against the Merger Proposal.

Section 14A of the Exchange Act, which was enacted as part of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, requires that we provide stockholders with the opportunity to vote to approve, on an advisory, non-binding basis, the payment of certain compensation that may be paid or become payable by Mirati to its named executive officers in connection with the Merger, as disclosed in the section of this proxy statement captioned “The Merger — Interests of Mirati’s Directors and Executive Officers in the Merger.”

We are asking stockholders to indicate their approval of the various items of compensation that may be paid or become payable by Mirati to its named executive officers in connection with the Merger. These payments are set forth in the section of this proxy statement captioned “The Merger — Interests of Mirati’s Directors and Executive Officers in the Merger — Golden Parachute Compensation,” and the accompanying footnotes. In general, the various plans and arrangements pursuant to which these compensation payments may be made have previously formed part of Mirati’s overall compensation program for our named executive officers.

Accordingly, we are seeking approval of the following resolution at the Special Meeting:

“RESOLVED, that the stockholders of Mirati Therapeutics, Inc. approve, on a nonbinding, advisory basis, the compensation that may be paid or become payable by Mirati to its named executive officers that is based on or otherwise relates to the Merger as disclosed pursuant to Item 402(t) of Regulation S-K in the section of the proxy statement captioned ‘The Merger — Interests of Mirati’s Directors and Executive Officers in the Merger — Golden Parachute Compensation.’”

Stockholders should note that the approval of this proposal is not a condition to completion of the Merger, and as an advisory vote, the result will not be binding on Mirati, the Board of Directors, Parent or the named executive officers. Further, certain payments under the underlying plans and arrangements are contractual in nature and not, by their terms, subject to stockholder approval. Accordingly, regardless of the outcome of the advisory vote, if the Merger is consummated our named executive officers will be eligible to receive the compensation that is based on or otherwise relates to the Merger in accordance with the terms and conditions of the underlying plans and agreements and the Merger Agreement.

We are asking you to approve a proposal to adjourn the Special Meeting to a later date or dates if necessary or appropriate to solicit additional proxies if there are insufficient votes to approve the Merger Proposal at the time of the Special Meeting. If stockholders approve this Adjournment Proposal, we could adjourn the Special Meeting and any adjourned session of the Special Meeting and use the additional time to solicit additional proxies, including proxies from stockholders that have previously returned properly executed proxies voting against approval of the Merger Proposal. Among other things, approval of the Adjournment Proposal could mean that, even if we had received proxies representing a sufficient number of votes against approval of the Merger Proposal such that the proposal to adopt the Merger Agreement would be defeated, we could adjourn the Special Meeting without a vote on the approval of the Merger Proposal and seek to convince the stockholders of those shares of our common stock to change their votes to votes in favor of approval of the Merger Proposal. Additionally, we may seek to adjourn the Special Meeting if a quorum is not present or otherwise at the discretion of the chairman of the Special Meeting.

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

This discussion of the Merger Agreement, the form of CVR Agreement and the Merger in this proxy statement is qualified in its entirety by reference to the Merger Agreement, which is attached to this proxy statement as Annex A, and the form of CVR Agreement, which is attached as Exhibit B to the Merger Agreement that is attached to this proxy statement as Annex A, each of which are incorporated into this proxy statement by reference. You should read and consider the Merger Agreement, which is the legal document that governs the Merger, carefully and in its entirety.

Mirati is a commercial-stage targeted oncology company developing novel therapeutics to address the genetic drivers of cancer. We approach all of our programs with a singular focus: to translate our deep understanding of the molecular drivers of cancer into better therapies and better outcomes for patients. For more information on our company, please visit www.mirati.com.

Mirati’s common stock is listed on Nasdaq under the symbol “MRTX.”

BMS was incorporated under the laws of the State of Delaware in August 1933 under the name Bristol-Myers Company, as successor to a New York business started in 1887. In 1989, Bristol-Myers Company changed its name to Bristol-Myers Squibb Company as a result of a merger. BMS is engaged in the discovery, development, licensing, manufacturing, marketing, distribution and sale of innovative medicines that help patients prevail over serious diseases on a global basis, primarily in the following therapeutic areas: oncology, hematology, immunology, cardiovascular and neuroscience.

BMS’s common stock, par value $0.10, is listed on the New York Stock Exchange under the symbol “BMY.”

Merger Sub is a wholly owned subsidiary of Parent and was formed on September 20, 2023, solely for the purpose of engaging in the transactions contemplated by the Merger Agreement and has not engaged in any business activities other than in connection with the transactions contemplated by the Merger Agreement.

Upon the terms and subject to the conditions of the Merger Agreement, if the Merger is completed, at the Effective Time, Merger Sub will merge with and into Mirati, and Mirati will continue as the Surviving Corporation and a wholly owned subsidiary of Parent. As a result of the Merger, our common stock will no longer be publicly traded, will be delisted from Nasdaq and will be deregistered under the Exchange Act, and Mirati will no longer file periodic reports with the SEC. If the Merger is completed, you will not own any shares of the capital stock of the Surviving Corporation.

The Effective Time will occur upon the filing of a certificate of merger with the Secretary of State of the State of Delaware (or at such later time as we, Parent and Merger Sub may agree and specify in the certificate of merger).

If the Merger Agreement is not adopted by our stockholders or if the Merger is not completed for any other reason, stockholders will not receive any payment for their shares in connection with the Merger. Instead, Mirati will remain an independent public company, our common stock will continue to be listed and traded on Nasdaq 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 stockholders will continue to be subject to the same risks and opportunities to which they are currently subject, including, without limitation, risks related to the highly competitive industry in which Mirati operates and risks related to adverse economic conditions.

Upon termination of the Merger Agreement under specified circumstances, Mirati will be required to pay Parent a termination fee of $168,000,000, or Mirati may be entitled to receive from Parent a reverse termination fee of $240,000,000, in each case upon the termination of the Merger Agreement. For more information please see the section of this proxy statement captioned “The Merger Agreement — Expenses — Termination Fees.”

Furthermore, if the Merger is not completed, and depending on the circumstances that caused the Merger not to be completed, it is likely that the price of our common stock will decline significantly. If that were to occur, it is uncertain when, if ever, the price of our common stock would return to the price at which it trades as of the date of this proxy statement.

Accordingly, if the Merger is not completed, 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. If the Merger is not completed, the Board of Directors will continue to evaluate and review Mirati’s business operations, strategic direction and capitalization, among other things, and will make such changes as are deemed appropriate and continue to seek to identify strategic alternatives to enhance shareholder value. If the Merger Agreement is not adopted by our stockholders or if the Merger is not completed for any other reason, there can be no assurance that any other transaction acceptable to the Board of Directors will be offered or that Mirati’s business, prospects or results of operation will not be adversely impacted.

At the Effective Time, each outstanding share of our common stock (other than the Excluded Shares and the Dissenting Shares) will be converted into the right to receive the Merger Consideration.

After the Merger is completed, you will have the right to receive the Merger Consideration, but you will no longer have any rights as a stockholder (except that stockholders who properly exercise, and do not subsequently withdraw, their appraisal rights will have the right to receive a payment for the “fair value” of their shares of our common stock as determined pursuant to an appraisal proceeding as contemplated by Section 262, as described in the section of this proxy statement captioned “— Appraisal Rights”).

With the support of the Board of Directors, management of Mirati regularly meets with other biotechnology and pharmaceutical companies regarding a variety of potential partnerships, licensing arrangements, joint ventures, collaborations and other strategic transactions. The Board of Directors also periodically evaluates Mirati’s historical performance, future growth prospects and long-term strategic plan and considers various strategic opportunities available to Mirati as well as ways to enhance shareholder value and Mirati’s performance and prospects, including in light of the business, competitive, regulatory, financing and economic environment and developments in Mirati’s industry . These reviews have included discussions as to whether Mirati should continue to execute on its strategy as a stand-alone company, pursue various partnerships, collaborations or licensing arrangements, seek to improve its capital structure or pursue a sale of the entire company or part of the company.

In connection with exploratory discussions of potential strategic transactions, in October 2020, Mirati entered into confidentiality agreements with BMS and two other global pharmaceutical companies, Party A and Party D. Following entry into these confidentiality agreements, Mirati from time-to-time shared limited

On March 23, 2022, Dr. Giovanni Caforio, Chief Executive Officer and Chairman of the Board of Directors of BMS, provided Mr. David Meek, Mirati’s Chief Executive Officer at the time, an oral preliminary non-binding proposal to acquire all of the outstanding shares of Mirati for a price of $125.00 per share in cash, which was subsequently confirmed in a non-binding written proposal (which we refer to as the “March 23, 2022 Proposal”), which was subject to BMS’s further due diligence. The one-day prior closing price of Mirati shares on March 22, 2022 was $85.49 per share.

On March 24, 2022, the Board of Directors held a meeting, attended by management of Mirati and representatives of Centerview Partners LLC (which we refer to as “Centerview”) and Skadden, Arps, Slate, Meagher and Flom LLP, Mirati’s outside M&A counsel (which we refer to as “Skadden”), to discuss the March 23, 2022 Proposal and other strategic parties that had expressed interest in Mirati and its programs, among other matters. A representative of Skadden discussed the fiduciary duties of the Board of Directors in connection with the review and evaluation of the March 23, 2022 Proposal. Following discussion, the Board of Directors determined that the March 23, 2022 Proposal was not sufficient to warrant granting BMS access to further due diligence information and instructed Centerview to convey this message to BMS. The Board of Directors also instructed Centerview to contact Party A, which had contacted Mirati from time to time and expressed interest in Mirati’s programs and potential opportunities for strategic collaborations.

On March 30, 2022, representatives of Centerview discussed with representatives of BMS the March 23, 2022 Proposal and, consistent with the Board of Directors’ instructions, conveyed that the March 23, 2022 Proposal was not sufficient to warrant granting BMS access to further due diligence information.

On March 31, 2022, at the direction of the Board of Directors, representatives of Centerview contacted representatives of Party A to discuss its potential interest in a strategic transaction involving Mirati.

On April 5, 2022, Dr. Caforio provided Mr. Meek a revised oral preliminary non-binding proposal, which was subsequently confirmed in a non-binding written proposal (which we refer to as the “April 5, 2022 Proposal”), to acquire all of the outstanding shares of Mirati for a price of $140.00 per share in cash, which proposal was subject to BMS’s further due diligence. The one-day prior closing price of Mirati shares on April 4, 2022 was $88.71 per share.

Also on April 5, 2022, a transaction committee of the Board of Directors (formed as a matter of convenience to facilitate efficient review and evaluation of a potential strategic transaction) (which we refer to as the “Transaction Committee”) held a meeting, attended by management of Mirati and representatives of Centerview and Skadden, to discuss the April 5, 2022 Proposal.

On April 8, 2022, the Board of Directors held a meeting, attended by management of Mirati and representatives of Centerview and Skadden, to discuss the April 5, 2022 Proposal, among other matters. After discussion, the Board of Directors determined that, while the April 5, 2022 Proposal was insufficient and needed to be improved, Mirati should provide BMS access to limited diligence materials and that Mirati should continue negotiations with BMS in order to obtain an improved proposal. Consistent with this instruction, Mirati provided representatives of BMS limited confidential due diligence materials focused on the latest clinical data available for adagrasib and Mirati’s other pipeline candidates.

On April 13, 2022, the Chief Executive Officer of Party A contacted Mr. Meek to communicate interest in pursuing a potential strategic transaction with Mirati.

On April 19, 2022, at the request of BMS, management of Mirati held a management presentation with representatives of BMS to discuss, among other topics, the latest clinical data available for adagrasib as well as the status of Mirati’s other pipeline candidates.

On April 26, 2022, management of Mirati held a follow-up call with representatives of BMS to address additional questions from BMS.

On May 9, 2022, representatives of BMS communicated to representatives of Centerview that, while it remained interested in a potential strategic transaction involving Mirati, it was unable to submit a revised proposal. The representatives of BMS cited the need for additional regulatory clarity as to whether Mirati’s adagrasib product candidate (for which clinical data had been obtained using a capsule formulation) was likely to receive Food and Drug Administration (which we refer to as the “FDA”) approval based on a proposed tablet formulation, further information on the dosing strategy for adagrasib and more mature first-line non-small cell lung cancer (which we refer to as “NSCLC”) data, among other matters. Later that day, the Transaction Committee held a meeting, with representatives of Centerview and Skadden in attendance, to discuss the latest status of BMS’s and Party A’s respective interest in a strategic transaction with Mirati.

On May 27, 2022, representatives of Party A communicated to representatives of Centerview that it did not expect to make a proposal for a strategic transaction at the current time, citing a need for more mature data on adagrasib, but that Party A remained interested in pursuing a potential strategic transaction in the future.

On June 18, 2022, the Chief Executive Officer of Party D met with Mr. Meek to discuss potential ways the two companies could collaborate. Party D and Mirati had previously discussed potential opportunities for strategic collaborations.

On June 23, 2022, the Board of Directors held a meeting, attended by management of Mirati and representatives of Centerview, where Mr. Meek and representatives of Centerview provided the Board of Directors with summary feedback from discussions with BMS and Party A.

On November 22, 2022, Bloomberg published an article reporting that Mirati had received acquisition interest from large pharmaceutical companies and was weighing strategic options, including a potential sale.

During the course of October through December 2022, BMS and Party A held various discussions with representatives of Mirati to review Mirati’s business activities including the latest data available for adagrasib, and to revisit their potential interest in a strategic transaction. On November 30, 2022 and December 2, 2022, respectively, BMS and Party A were provided with the non-public data results described below as the December 5, 2022 Results, among other diligence items requested.

On December 4, 2022, Dr. Caforio provided to Mr. Meek an oral preliminary non-binding proposal to acquire all of the outstanding shares of Mirati for a price of $124.00 per share in cash, subject to BMS’s further due diligence, which was subsequently confirmed in a non-binding written proposal (which we refer to as the “December 4, 2022 Proposal”). The one-day prior closing price of Mirati shares on December 2, 2022 was $96.25 per share.

On December 5, 2022, the Board of Directors held a meeting, attended by management of Mirati and representatives of Centerview and Skadden, to discuss the December 4, 2022 Proposal. Following discussion, the Board of Directors instructed Centerview to communicate to Party A, which was in the process of reviewing certain non-public due diligence materials provided by Mirati, that Mirati had received a high level of interest from another party and wanted to clarify Party A’s status on its evaluation of a potential strategic transaction with Mirati. Representatives of Centerview subsequently contacted representatives of Party A to convey this message.

Following the December 5, 2022 meeting of the Board of Directors, representatives of Evercore Group LLC (which we refer to as “Evercore”) and Morgan Stanley & Co. LLC (which we refer to as “Morgan Stanley”), financial advisors to BMS, contacted representatives of Centerview to confirm the Board of Directors’ receipt of the December 4, 2022 Proposal.

Later on December 5, 2022, Mirati published a press release with preliminary results from the KRYSTAL-7 Phase 2 trial and KRYSTAL-1 Phase 1b cohort evaluating adagrasib (400mg twice daily) concurrently combined with pembrolizumab in patients for the treatment of first-line NSCLC harboring a KRASG12C mutation across

On December 7, 2022, Dr. Caforio informed Mr. Meek that, in light of recent events, BMS needed more time to evaluate Mirati and that BMS was no longer able to proceed with a transaction on the terms described in the December 4, 2022 Proposal. Also on December 7, 2022, representatives of Evercore and Morgan Stanley informed representatives of Centerview that BMS would need more time to evaluate Mirati.

On December 12, 2022, Mirati announced the FDA completed its review of Mirati’s NDA and granted accelerated approval for KRAZATI.

On December 14, 2022, representatives of Party A communicated to representatives of Centerview that it was not able to submit a proposal for a potential transaction involving Mirati at the current time.

Also on December 14, 2022, the Board of Directors held a meeting, attended by management of Mirati and representatives of Centerview and Skadden, during which, among other matters, the Board of Directors received an update that BMS and Party A did not intend to continue pursuing a potential transaction at the current time.

Beginning in December 2022, at the direction of the Board of Directors, members of management began outreach to select potential counterparties for an ex-U.S. partnership for adagrasib, including Party C. Following discussions with potential counterparties (none of which made a binding proposal), Mirati ultimately chose to not move forward with an ex-U.S. partnership. None of the confidentiality agreements entered into by Mirati in connection with a potential ex-U.S. partnership for adagrasib contained a standstill that remained effective following the execution of the Merger Agreement and the announcement of the Transactions, except for the standstills in three confidentiality agreements with counterparties who are permitted to make confidential proposals to the Board of Directors.

On December 21, 2022, BMS sent a letter to Mirati with a preliminary non-binding proposal to co-develop and co-commercialize adagrasib globally (ex-China) (which we refer to as the “BMS Collaboration Proposal”), which proposal was subject to BMS’s further due diligence. The BMS Collaboration Proposal contemplated that Mirati would receive a $500 million upfront payment plus up to $485 million in regulatory milestones and $450 million in sales-based milestones, and tiered royalties based on global net sales. The BMS Collaboration Proposal also contemplated that Mirati would issue shares representing 19.9% of its outstanding shares to BMS at a 30% premium to market. Following discussion with members of the Board of Directors, Mr. Hasnain communicated to Dr. Caforio that the Board of Directors did not view a global partnership for adagrasib as an attractive strategic option for maximizing value for Mirati’s stockholders at the current time.

In early January 2023, the Chief Financial Officer of Party B, a global pharmaceutical company, contacted Mr. Meek indicating potential strategic interest and proposed to schedule a meeting to review Mirati’s programs. On January 11, 2023, Mirati and Party B entered into a confidentiality agreement for purposes of discussing a potential strategic transaction, which confidentiality agreement was amended on February 25, 2023 to add a standstill provision, which ceased to be effective upon the execution of the Merger Agreement and the announcement of the Transactions.

On February 27, 2023, a representative of BMS contacted Mr. Meek to request a meeting to discuss the latest data available for adagrasib, in the context of revisiting BMS’s interest in a potential strategic transaction with Mirati.

On March 1, 2023, at Party B’s request, management of Mirati met with representatives of Party B and provided an overview of the latest data available for adagrasib and Mirati’s pipeline programs. At this meeting, Party B expressed its interest in a strategic transaction with Mirati.

Management of Mirati subsequently held discussions with representatives of BMS and Party B on March 3, 2023 and March 6, 2023, respectively, to provide an update on Mirati’s clinical data. In the days following discussions, representatives of BMS and Party B each communicated to representatives of Mirati that they remained interested in a potential strategic transaction involving Mirati, but that more mature data on the use of KRAZATI in patients with first-line NSCLC was needed.

On April 28, 2023, at the request of Party B, management of Mirati and representatives of Centerview held a follow-up discussion to provide an update on the latest data available for KRAZATI. In the days following this meeting, representatives of Party B communicated to representatives of Mirati that Party B was not prepared to make an offer to acquire Mirati.

On May 5, 2023, at the request of BMS, management of Mirati and representatives of Centerview met with representatives of BMS to provide an update on the latest data available for KRAZATI. In the days following this meeting, representatives of BMS communicated to representatives of Mirati that BMS was pausing in its consideration of a potential transaction given its internal view of valuation for Mirati relative to Mirati’s then current trading prices. The closing price of Mirati shares on May 5, 2023 was $45.96 per share.

On May 23, 2023, the Board of Directors held a meeting, attended by management of Mirati and representatives of Centerview and Skadden, during which, among other matters discussed, the Board of Directors received an update on recent feedback from Party B and BMS.

On May 24, 2023, Mirati announced that its SAPPHIRE study on sitravatinib, an investigational spectrumselective kinase inhibitor, did not meet its primary endpoint of overall survival at the final analysis.

On July 21, 2023, Mirati announced that the European Medicine Agency’s Committee for Medicinal Products for Human Use issued a negative opinion on the Conditional Marketing Authorisation Application for KRAZATI (adagrasib) for treatment of patients with KRASG12C-mutated advanced NSCLC. Mirati also announced that it disagreed with the opinion and intended to request a formal re-examination. The closing price of Mirati shares on July 21, 2023 was $31.31 per share.

Following Mirati’s announcement on July 21, 2023, as part of the Board of Directors’ continuous evaluation and consideration of potential strategic opportunities for maximizing value for Mirati’s stockholders, the Board of Directors instructed management to begin the outreach for selecting potential counterparties for a global partnership for adagrasib, including potential counterparties previously contacted about an ex-U.S. partnership for adagrasib. BMS, Party A, Party C and Party D were included in this process. Party A declined to participate in this process, and Party D ultimately communicated that it would not pursue the process. Party B was not included in this process given that prior interactions with Party B focused on an acquisition of Mirati before Party B disengaged. No proposals were ultimately made by any of the potential counterparties contacted as part of this outreach (other than the BMS Collaboration Proposal that had been made by BMS prior to the process), although discussions remained active with a number of these parties until the execution of the Merger Agreement and announcement of the Transactions. None of the confidentiality agreements entered into by Mirati in connection with a potential global partnership for adagrasib contained a standstill that remained effective following the execution of the Merger Agreement and the announcement of the Transactions.

On August 8, 2023, Mirati announced that its Chief Executive Officer, David Meek, would depart the company, based on mutual agreement. Mr. Meek’s departure was not the result of a disagreement with Mirati on any matter related to Mirati’s operations, policies or practices. The Board of Directors appointed director Charles M. Baum, M.D., Ph.D., as Interim Chief Executive Officer of Mirati.

From June to August 2023, the Board of Directors reviewed a potential equity financing transaction to fund ongoing operations. On August 11, 2023, Mirati closed an underwritten public offering in which it sold 9,669,632 shares of its common stock and, to certain investors, pre-funded warrants to purchase 1,121,736 shares of its common stock. The offering price to the public was $27.80 per share and $27.799 per pre-funded warrant. Mirati senior management prepared long-term revenue information to assist the Board of Directors in its review and evaluation of this equity financing, which were provided to the Board of Directors during the period from June 2023 through early August 2023. For a description of the financial projections presented during this period, please see the description of the June 2023 Management Revenue Projections in the section entitled “— Certain Financial Projections.”

On August 28, 2023, the Board of Directors held a meeting, including Mr. John B. Moriarty, Jr., J.D., Chief Legal Officer and Corporate Secretary of Mirati, and representatives of Skadden, to form a new transaction committee comprised of all of the directors other than director Aaron Davis (the “New Transaction Committee”), who was at the time a director of another company developing a drug in a similar class to one of Mirati’s product candidates, and to delegate to the New Transaction Committee all power and authority of the Board of Directors with respect to evaluating recent developments; provided that any potential transaction involving Mirati would need to be approved by the full Board of Directors.

Following the August 28, 2023 meeting of the Board of Directors, the New Transaction Committee held a meeting on August 28, 2023, also attended by management of Mirati, and representatives of Centerview and Skadden, to discuss the August 28 Proposal. Representatives of Skadden discussed with the members of the New Transaction Committee their fiduciary duties in connection with the review and evaluation of the August 28 Proposal. Members of the New Transaction Committee discussed the need for the management of Mirati to develop a full set of long-term projections in order to review and evaluate the August 28 Proposal and any future proposals in comparison to Mirati’s prospects as a stand-alone enterprise, and directed the management of Mirati to create such long-term projections. The members of the New Transaction Committee also discussed BMS’s engagement history and prior proposals, as well as the risks and potential benefits of conducting outreach to a select number of additional parties to determine whether another interested party would emerge to compete with BMS. Following discussion of potentially interested counterparties (including parties involved in Mirati’s ongoing global partnering process for adagrasib) and the risk of leaks and market rumors that could be disruptive to interactions with BMS and disruptive to Mirati employees, the New Transaction Committee determined that Party A was unlikely to engage given its recent internal strategies priorities and authorized Centerview to contact Party B to communicate that Mirati was considering an acquisition proposal from another party. The Transaction Committee also authorized management of Mirati to communicate to BMS that Mirati anticipated responding to the August 28 Proposal the next week.

In accordance with the instructions of the New Transaction Committee, on August 29, 2023, a representative of Centerview met with the Chief Financial Officer of Party B and informed them that Mirati had received an acquisition proposal from another party.

On August 30, 2023 Mr. Hasnain informed Dr. Caforio that Mirati would respond to the August 28 Proposal the following week.

On August 31, 2023, a representative of Party B responded to a representative of Centerview that Party B was not interested in participating in a sale process for Mirati, citing Party B’s own internal strategic priorities.

Also on August 31, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. The Board of Directors determined that further review and evaluation of the August 28 Proposal and other strategic alternatives no longer required the use of the New Transaction Committee, as Mr. Davis had resigned from the board of directors of the company developing a drug in a similar class to one of Mirati’s product candidates, and that such review and evaluation could be conducted by the full Board of Directors. Representatives of Centerview updated the Board of Directors that Party B had informed representatives of Centerview that it did not intend to submit a proposal to acquire Mirati. After further discussion of the risk of leaks and market rumors that could be disruptive to interactions with BMS and disruptive to Mirati employees, and discussion of Mirati’s prior outreach during the ongoing partnering process for adagrasib, it was the consensus of the Board of Directors that additional outreach was not in the best interests of Mirati at such time.

On September 5, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. Prior to representatives of Centerview joining the meeting, representatives of Skadden reviewed with the Board of Directors the disclosures provided by Centerview with respect to BMS with respect to any potential conflicts of interest that could affect Centerview’s abilities to fulfill its responsibilities as financial advisor to Mirati, and members of management discussed the terms for the

On September 6, 2023, Mr. Hasnain and Dr. Baum spoke with Dr. Caforio and, in accordance with instructions from the Board of Directors, indicated that Mirati would be willing to engage with BMS if BMS improved its offer to $82.00 per share (which we refer to as the “September 6 Counterproposal”). Dr. Caforio informed Mr. Hasnain and Dr. Baum that he would reconvene the board of directors of BMS and would likely respond in a few days.

Also on September 6, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden, during which Mr. Hasnain and Dr. Baum updated the Board of Directors on the conversation between Dr. Caforio, Mr. Hasnain, and Dr. Baum concerning the September 6 Counterproposal occurring earlier that day.

On September 12, 2023, Dr. Caforio conveyed to Mr. Hasnain and Dr. Baum BMS’s revised non-binding proposal (before sending a letter reflecting the same) to acquire all of the outstanding shares of Mirati for a price of $66.00 per share in cash as upfront payment plus two $5.00 per share CVRs, for a cumulative total of $10.00 per share, with respective milestone payments of $5.00 triggered by NDA acceptance of MRTX 1719 (PRMT5) in 2L+ NSCLC and by NDA acceptance of MRTX 1133 (G12D) in 2L+ PDAC (which we refer to as the “September 12 Proposal”). The September 12 Proposal also indicated that BMS was targeting a transaction announcement within two weeks.

On September 13, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. Members of the Board of Directors, Mirati management, and representatives of Centerview discussed the September 12 Proposal, the implied value of the two CVRs and potential strategies for responding to BMS. Members of the Board of Directors and Mirati management also discussed upcoming events that could impact discussions with BMS, including upcoming competitor data releases, Mirati’s upcoming release of third quarter results and the status of Mirati’s ongoing process to identify a global partner for adagrasib. Following discussion, the Board of Directors determined that Mirati management should respond to BMS with a counterproposal of $71.00 per share upfront plus one $5.00 per share CVR triggered by NDA acceptance of MRTX 1719 (PRMT5) in 2L+ NSCLC (which we refer to as the “September 13 Counterproposal”). Later that day, Mr. Hasnain and Dr. Baum spoke with Dr. Caforio and communicated the September 13 Counterproposal.

On September 15, 2023, Dr. Caforio spoke with Mr. Hasnain and Dr. Baum and communicated a revised offer by BMS to acquire all of the outstanding shares of Mirati for $68.00 per share upfront with no CVRs (which we refer to as the “September 15 Proposal”). Dr. Caforio also communicated BMS’s desire to announce a transaction by September 25, 2023.

Also on September 15, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. Mr. Hasnain and Dr. Baum updated the Board of Directors on the September 15 Proposal and that, in response to questions from Mr. Hasnain and Dr. Baum during the call with Dr. Caforio, Dr. Caforio indicated that he did not expect BMS would be able to increase its offer. The members of the Board of Directors discussed the September 15 Proposal and proposed timing with representatives of Centerview and Skadden, including the risks and opportunities for Mirati affecting potential

Also on September 15, 2023, after the meeting of the Board of Directors, Mr. Hasnain discussed the September 15 Proposal with Dr. Caforio consistent with the instruction from the Board of Directors. Dr. Caforio indicated that $68.00 per share was the highest consideration that BMS expected to be able to provide.

On September 16, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. Mr. Hasnain updated the Board of Directors on his discussion with Dr. Caforio the day prior. Members of the Board of Directors discussed potential responses to the September 15 Proposal, weighing the potential risks and benefits of requesting a CVR in addition to upfront cash consideration. The Board of Directors discussed the delay and uncertainty associated with negotiating a CVR (even if BMS was willing to consider one) given the desire for a September 25, 2023 announcement. Next, representatives of Skadden discussed the material terms of the draft merger agreement to be provided to BMS’s counsel. Following discussion, the Board of Directors authorized Mr. Hasnain and Dr. Baum to respond to Dr. Caforio that Mirati was willing to proceed with confirmatory due diligence and the negotiation of a merger agreement on the basis of the September 15 Proposal with a targeted announcement date of September 25, 2023. Following this discussion, representatives of Centerview left the meeting and, after discussion of the proposed terms, the Board of Directors approved the engagement letter with Centerview.

Later on September 16, 2023, Skadden sent a draft merger agreement to Kirkland & Ellis LLP, BMS’s outside counsel (which we refer to as “Kirkland”). The draft merger agreement contemplated a one-step merger structure as requested by BMS in its August 28 Proposal.

On September 17, 2023, representatives of Mirati granted BMS access to Mirati’s virtual data room. Following admission to the virtual data room, representatives of BMS and Mirati held meetings and discussions from September 18, 2023 through the announcement of the Transactions as part of BMS’s due diligence process (other than during the period described below in which Mirati suspended due diligence and negotiations).

On September 20, 2023, Kirkland sent a revised draft of the Merger Agreement, following which, discussions and negotiations among representatives of Skadden and Kirkland continued through the announcement of the Transactions (other than during the period described below in which Mirati suspended due diligence and negotiations).

On September 23, 2023, representatives of BMS, management of Mirati and representatives of Centerview met to discuss the KRYSTAL-7 clinical trial design for the use of KRAZATI in patients with first-line NSCLC, feedback from the FDA pertaining to KRYSTAL-7 and the enrollment assumptions associated with KRYSTAL-7.

Following completion of BMS’s due diligence, on September 24, 2023, Dr. Caforio contacted Mr. Hasnain to explain that BMS was revising its acquisition proposal to $56.00 per share upfront with one CVR for $10.00 per share related to MRTX 1719 (PRMT5), payable upon NDA filing acceptance by the FDA for MRTX 1719 in secondline+ NSCLC, which was followed up with a non-binding written proposal (which we refer to as the “September 24 Proposal”). The letter for the September 24 Proposal explained that the proposal was affected by diligence findings that impacted BMS’s views on KRAZATI program timelines, as well as the status of one of Mirati’s early-stage pipeline programs. The September 24 Proposal indicated that BMS was targeting an announcement by September 26, 2023.

Later on September 24, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. Members of the Board of Directors, Mirati management and representatives of Centerview discussed the September 24 Proposal and discussed the two key areas of BMS’s due diligence raised in the September 24 Proposal, including the risk that these matters could also adversely affect the outcome of Mirati’s ongoing global partnering discussions for adagrasib, if Mirati chose to remain a stand-alone company. Following discussion, the Board of Directors determined that Mr. Hasnain should communicate to Dr. Caforio that Mirati was not prepared to engage further on the basis of the September 24 Proposal, and that Mirati should terminate virtual data room access for BMS.

On September 26, 2023, a representative of BMS and a representative of Centerview spoke. The BMS representative gave further explanation to the BMS position on the September 24 Proposal and inquired about the potential to shift to a partnership.

On September 28, 2023, the Board of Directors held a regularly scheduled quarterly meeting. As part of this meeting, the Board of Directors reviewed potential alternative scenarios for Mirati continuing as a stand-alone company. In connection with such discussions, the Board of Directors reviewed the September 2023 Management Revenue Projections, which were different from the revenue information reflected in the Management Projections, as further described in the section entitled “— Certain Financial Projections.” The members of the Board of Directors also discussed the September 26, 2023 BMS outreach to Centerview and potential counterproposals to BMS, and determined that Mirati should convey a counterproposal to BMS within the parameters discussed at the meeting, after seeking further advice from Centerview. Following this meeting, members of the Board of Directors met with representatives of Centerview and, after discussion of the parameters discussed by the Board of Directors, directed Centerview to convey a counterproposal to BMS consisting of $58.00 per share, one $10.00 per share CVR related to MRTX 1719 (PRMT5) and one $10.00 per share CVR related to KRAZATI, while remaining receptive to additional discussion of structures for CVRs.

On September 29, 2023, at the direction of the Board of Directors, representatives of Centerview proposed to a representative of BMS a counterproposal for BMS to acquire all of the outstanding shares of Mirati for $58.00 per share, one $10.00 per share CVR related to MRTX 1719 (PRMT5) and one $10.00 per share CVR related to KRAZATI, expressing a desire for nearer term CVR milestone triggers and offering to explore additional potential constructs for CVRs that would provide meaningful risk-adjusted value to Mirati shareholders (which we refer to as the “September 29 Counterproposal”).

On October 1, 2023, representatives of BMS, management of Mirati, and representatives of Centerview held a follow-up discussion on the KRYSTAL-7 clinical trial design feedback from the FDA pertaining to KRYSTAL-7 and the enrollment assumptions associated with KRYSTAL-7.

On October 2, 2023, a representative of BMS called Dr. Baum and informed him that BMS was unable to meaningfully increase the upfront cash consideration from the $56.00 offered in the September 24 Proposal, but was open to discussing the CVR component of the proposal.

Also on October 2, 2023, the Chief Executive Officer of Party C, which had actively participated in due diligence for a global partnering transaction, contacted Dr. Baum and expressed interest in a possible whole company transaction. Given the relative size of the two companies, a transaction with Party C would have required a significant stock component. Later that day, Dr. Baum contacted a representative of Party C and indicated that if Party C was interested in pursuing a whole company transaction it should contact Centerview.

On October 4, 2023, following consultation with members of the Board of Directors, Dr. Baum and a representative of Centerview contacted representatives of BMS to communicate a counterproposal of $58.00 per share in upfront payment, a $5.00 per share CVR related to MRTX 1133 (G12D) and a $15.00 per share CVR related to MRTX 1719 (PRMT5), again expressing a desire for nearer term CVR milestone triggers and offering to explore additional potential constructs for CVRs that would provide meaningful risk-adjusted value to Mirati shareholders (which we refer to as the “October 4 Counterproposal”).

On October 5, 2023, the FDA Oncologic Drugs Advisory Committee voted 10-2 that the endpoint for the LUMAKRAS® CodeBreaK-200 trial, a clinical trial for a competing product candidate by Amgen Inc., could not be reliably interpreted.

Also on October 5, 2023, at 2:30 P.M. Eastern Time, Bloomberg published an article titled “Sanofi Said to Weigh Acquisition of Cancer Drugmaker Mirati” reporting that Sanofi was exploring a potential acquisition of Mirati. At that time, Mirati was not engaged in discussions with Sanofi related to a potential acquisition. Mirati’s closing price on October 5, 2023 increased by 45% as compared to the closing price on October 4, 2023.

On October 6, 2023, Mr. Hasnain and Dr. Baum discussed the October 4 Counterproposal with representatives of BMS, and following such discussions BMS made a revised proposal to acquire all of the outstanding shares of Mirati for $58.00 per share in upfront payment and one $12.00 per share CVR based on NDA acceptance for MRTX1719 (PRMT5) in second line+ NSCLC (which we refer to as the “October 6 Proposal”). BMS also expressed that the October 6 Proposal was contingent on the parties announcing a transaction by October 8, 2023. Following receipt of the October 6 Proposal, Mr. Hasnain and Dr. Baum updated individual members of the Board of Directors in advance of the meeting that took place on October 7, 2023 as described below.

Also on October 6, 2023, Kirkland provided a markup of the draft merger agreement and an initial draft of the CVR agreement, following which, discussions and negotiations among representatives of Kirkland and Skadden continued until the signing of the merger agreement and CVR agreement on October 8, 2023. The key issues negotiated and resolved in the draft merger agreement included the parties’ obligations to seek regulatory approvals for the transaction, the size of the reverse termination fee payable by BMS in certain circumstances where regulatory approvals are not obtained, the ability of the Board of Directors to change its recommendation in circumstances other than a superior proposal, the non-solicitation provisions that prohibit Mirati from soliciting and negotiating with third parties to enter into an agreement for an alternative business combination transaction and the related termination rights and termination fee payable by Mirati in such instances, the treatment of employee equity awards and various executive and employee compensation matters (for a summary of these matters affecting executive officers, please see the section of this proxy statement titled “— Interests of Mirati’s Directors and Executive Officers in the Merger”). The key issues negotiated and resolved in the draft CVR agreement included the description of the accepted NDA that would trigger the payment milestone and the time period during which the payment milestone could be achieved. Later in the day on October 6, 2023, in connection with the negotiation of the merger agreement and CVR agreement, Kirkland and certain representatives of BMS were granted access to the virtual data room previously provided to BMS by Mirati.

Also on October 6, 2023, a representative of Centerview met with representatives of Party D at a previously scheduled meeting, during which the representatives of Party D indicated they were not interested in a strategic transaction with Mirati.

Also on October 6, 2023, Kirkland provided an initial draft of a voting agreement, to be entered into between BMS and certain affiliates of Boxer Capital, following which, discussions and negotiations among representatives of Kirkland and Boxer Capital continued until the signing of the voting agreement on October 8, 2023.

On October 7, 2023, the Board of Directors held a meeting, also attended by management of Mirati, and representatives of Centerview and Skadden. The members of the Board of Directors, Mirati management and representatives of Centerview discussed the September 29 Counterproposal, subsequent discussions as to alternative CVR structures with BMS and the October 6 Proposal, as well as BMS’s desire to announce a transaction by October 8, 2023. Representatives of Centerview discussed with the Board of Directors the financial analyses conducted by Centerview, including the assumptions made, procedures followed, matters considered and qualifications and limitations. Representatives of Skadden then discussed with the Board of Directors the material terms of the proposed merger agreement and CVR agreement and the voting agreement between BMS and certain affiliates of Boxer Capital. Representatives of Skadden then discussed with the Board of Directors the treatment of equity awards and the compensation arrangements proposed to be agreed between Mirati and BMS (for a summary of these matters affecting executive officers, please see the section of this proxy statement titled “— Interests of Mirati’s Directors and Executive Officers in the Merger”). After further discussion of BMS’s October 6 Proposal, including discussion of the risks and opportunities for Mirati discussed at previous meetings, the Board of Directors directed Mirati management and Mirati’s advisors to continue to negotiate and finalize the terms of the merger agreement and related documentation with BMS on the basis of the October 6 Proposal and to seek to announce a transaction by October 8, 2023.

After the October 8, 2023 meeting of the Board of Directors, Mirati, BMS, and Merger Sub executed the Merger Agreement, and BMS and certain affiliates of Boxer Capital executed the Voting Agreement. On October 8, 2023, Mirati and BMS issued a joint press release announcing the execution of the Merger Agreement and related documentation.

The Board of Directors has unanimously (1) determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are advisable and fair to, and in the best interest of, Mirati and its stockholders; (2) declared it advisable for Mirati to enter into the Merger Agreement; (3) approved the execution, delivery and performance by Mirati of the Merger Agreement and the consummation of the transactions contemplated thereby, including the Merger; (4) directed that the Merger Agreement be submitted to the Mirati stockholders for adoption; and (5) recommended that Mirati stockholders adopt the Merger Agreement.

In evaluating the Merger Agreement and the Transactions, including the Merger, the Board of Directors consulted with outside legal counsel, its financial advisors and Mirati’s senior management. In reaching their decision to approve the Merger Agreement, and in recommending that Mirati’s stockholders vote in favor of the adoption of the Merger Agreement, the Board of Directors considered numerous positive factors relating to the Merger Agreement, the Merger and the other Transactions, including the following material factors (which factors are not necessarily presented in order of relative importance):

In the course of reaching the determinations and decisions and making the recommendation described above, the Board of Directors, in consultation with Mirati’s senior management, outside legal counsel and financial advisors, also considered the risks and potentially negative factors relating to the Merger Agreement, the Merger and the other Transactions, including the following material factors (which factors are not necessarily presented in order of relative importance):

The Board of Directors believed that, overall, the potential benefits of the Merger to Mirati’s stockholders substantially outweighed the risks and uncertainties of the Merger.

The foregoing discussion of factors considered by the Board of Directors contains the material factors considered by the Board of Directors, but is not in any way intended to be exhaustive. In light of the variety of factors considered in connection with its evaluation of the Merger, the Board of Directors did not find it practicable to, and did not, quantify or otherwise assign relative weights to the specific factors considered in reaching its determinations and recommendations. Each member of the Board of Directors applied his or her own business judgment to the process and may have given different weight to different factors. The Board of Directors did not undertake to make any specific determination as to whether any factor or any particular aspect of a factor supported or did not support its ultimate determination. Rather, the Board of Directors based its recommendation on the totality of the information presented.

On October 8, 2023, Centerview rendered to the Board of Directors its oral opinion, subsequently confirmed in a written opinion dated October 8, 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 by Centerview in preparing its opinion, the Consideration to be paid to the holders of shares of our common stock (other than Excluded Shares) 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 October 8, 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 C and is incorporated herein by reference. The summary of the written opinion of Centerview set forth below is qualified in its entirety to the full text of Centerview’s written opinion attached as Annex C. Centerview’s financial advisory services and opinion were provided for the information and assistance of the Board of Directors (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transactions and Centerview’s opinion only addressed the fairness, from a financial point of view, as of the date thereof, to the holders of shares of our common stock (other than Excluded Shares) of the 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 Transactions and does not constitute a recommendation to any

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 the senior management and representatives of Mirati regarding their assessment of the Internal Data. In addition, Centerview reviewed publicly available financial and stock market data, including valuation multiples, for Mirati and compared that data with similar data for certain other companies, the securities of which are publicly traded, in lines of business that Centerview deemed relevant. Centerview also compared certain of the proposed financial terms of the Transactions with the financial terms, to the extent publicly available, of certain other transactions that Centerview deemed relevant, and conducted such other financial studies and analyses and took into account such other 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 Mirati’s consent, Centerview relied upon such information as being complete and accurate. In that regard, Centerview assumed, at Mirati’s direction, that the Internal Data (including, without limitation, the Management Projections) were reasonably prepared on bases reflecting the best currently available estimates and judgments of the management of Mirati as to the matters covered thereby and Centerview relied, at Mirati’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 Mirati’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 Mirati, 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 Mirati. Centerview assumed, at Mirati’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 Mirati’s direction, that the Transactions will be consummated on the terms set forth in the Merger 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 Transactions, 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 Mirati, or the ability of Mirati to pay its obligations when they come due, or as

Centerview’s opinion expressed no view as to, and did not address, Mirati’s underlying business decision to proceed with or effect the Transactions, or the relative merits of the Transactions as compared to any alternative business strategies or transactions that might be available to Mirati or in which Mirati 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 shares of our common stock (other than Excluded Shares) of the 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 Transactions, including, without limitation, the structure or form of the Transactions, the form or terms of the CVR 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 Transactions, including, without limitation, the fairness of the Transactions or any other term or aspect of the Transactions to, or any consideration to be received in connection therewith by, or the impact of the Transactions on, the holders of any other class of securities, creditors or other constituencies of Mirati 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 Mirati or any party, or class of such persons in connection with the Transactions, whether relative to the Consideration to be paid to the holders of the shares of our common stock (other than Excluded Shares) 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’ written opinion. Centerview’s opinion does not constitute a recommendation to any stockholder of Mirati or any other person as to how such stockholder or other person should vote with respect to the Merger Proposal or otherwise act with respect to the Transactions or any other matter. Centerview’s financial advisory services and its written opinion were provided for the information and assistance of the Board of Directors (in their capacity as directors and not in any other capacity) in connection with and for purposes of its consideration of the Transactions. The issuance of Centerview’s opinion was approved by the Centerview Partners LLC Fairness Opinion Committee.

The following is a summary of the material financial analyses prepared and reviewed with the Board of Directors in connection with Centerview’s opinion, dated October 8, 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 Mirati. Some of the summaries of the financial analyses set forth below include information presented in tabular format. In order to fully understand the financial analyses, the tables must be read together with the text of each summary, as the tables alone do not constitute a complete description of the financial analyses performed by Centerview. Considering the data in the tables below without considering all financial analyses or factors or the full narrative description of such analyses or factors, including the methodologies and assumptions underlying such analyses or factors, could create a misleading or incomplete view of the processes underlying Centerview’s financial analyses and its opinion. 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 Mirati or any other parties to the Transactions. None of Mirati, Parent, 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 Mirati do not purport to be appraisals or reflect the prices at which Mirati may actually be sold.

Centerview conducted an analysis of the Consideration to be paid to the holders of shares of our common stock (other than Excluded Shares) pursuant to the Merger Agreement and the CVR Agreement. Such Consideration is equal, on a per share basis, to $58.00 upfront per share in cash together, and not separately, with one CVR which could potentially result in an additional one-time contingent cash payment of $12.00 per CVR contingent upon, and subject to, the achievement of the CVR Product Milestone, as described more fully in the section captioned “Form of Contingent Value Rights Agreement.”

For analytical purposes, assuming that for one CVR, the holders thereof receive a payment equal to $12.00 upon the achievement of the milestone, based solely on the assessments of Mirati’s management as to (i) the probability of realizing the milestone and (ii) the estimated timing of achievement of the milestone, and discounting the probability-adjusted milestone payment back to the valuation date using the midpoint of a range of discount rates from 10.5% - 12.0% based on Centerview’s analysis of Mirati’s weighted average cost of capital, Centerview calculated an illustrative net present value for one CVR of $3.17.

Solely for purposes of the financial analyses summarized below, the term “illustrative assumed per share merger consideration” refers to an aggregate assumed implied per Share value of $61.17 per share (which we refer to as the “Implied Consideration Value”), equal, on a per share basis, to $58.00 upfront consideration plus the illustrative net present value of the CVR of $3.17, based on the midpoint of the range of discount rates, as set forth above. However, there is no guarantee that any of the conditions for the CVR Milestone Payment pursuant to the CVR Agreement will be satisfied, and if satisfied, when such conditions will be satisfied.

Centerview reviewed and analyzed certain financial information of Mirati and compared it to corresponding financial information of certain publicly traded biopharmaceutical companies (which companies are referred to as the “selected companies” in this summary of Centerview’s opinion) that Centerview, based on its experience and professional judgment, deemed relevant to consider in relation to Mirati.

However, because none of the selected companies is exactly the same as Mirati, Centerview believed that it was inappropriate to, and therefore did not, rely solely on the quantitative results of the selected public company analysis. Accordingly, Centerview also made qualitative judgments, based on its experience and professional judgment, concerning differences between the business, operational and/or financial characteristics and other factors that could affect the public trading values of the selected companies and Mirati in order to provide a context in which to consider the results of the quantitative analysis.

Using publicly available information obtained from SEC filings and other data sources as of October 6, 2023, Centerview calculated, for each selected company, such company’s enterprise value (calculated as the equity value (determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units, performance stock units and other convertible securities) plus the book value of debt and certain liabilities less cash and cash equivalents) as a multiple of Wall Street research analyst consensus estimated revenue for calendar year 2027 (“EV/2027E Revenue Multiple”).

Based on this analysis and other considerations that Centerview deemed relevant in its professional judgment and experience, related to, among other things, differences in the business, operational and/or financial conditions and prospects of Mirati and the companies included in the selected public company analysis, Centerview selected a reference range of EV/2027E Revenue Multiples of 3.0x to 5.0x. Centerview applied this reference range of EV/2027E Revenue Multiples to Mirati’s estimated calendar year risk-adjusted 2027 revenue excluding one-time items of $388 million as set forth in the Management Projections and added to it Mirati’s estimated net cash, as of December 31, 2023, of $861 million, provided by the management of Mirati set forth in the Internal Data, and divided the results of the foregoing calculations by the number of fully-diluted outstanding shares of our common stock (determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units and performance stock units) as of October 6, 2023 based on information provided by the management of Mirati and as set forth in the Internal Data. This analysis resulted in an implied per share equity value range for the shares of our common stock of approximately $24.65 to $34.05, rounded to the nearest $0.05. Centerview then compared this range to the Implied Consideration Value of $61.17 per Share to be paid to the holders of shares of our common stock (other than Excluded Shares) pursuant to the Merger Agreement and the CVR Agreement.

Centerview reviewed and analyzed certain information of Mirati and compared it to corresponding financial information of certain transactions involving publicly traded biopharmaceutical companies (which transactions are referred to as the “selected transactions” in this summary of Centerview’s opinion) that Centerview, based on its experience and professional judgment, deemed relevant to consider in relation to Mirati and the Transactions. Although none of the selected transactions is identical or directly comparable to the Merger, the companies included in the selected transactions were selected by Centerview because, among other reasons, they are publicly traded biopharmaceutical companies with certain business, operational and/or financial characteristics that, for purposes of Centerview’s analysis, may be considered similar to the Merger.

However, because none of the selected transactions is exactly the same as the Merger, Centerview believed that it was inappropriate to, and therefore did not, rely solely on the quantitative results of the selected precedent transactions analysis. Accordingly, Centerview also made qualitative judgments, based on its experience and professional judgment, concerning differences between the business, operational and/or financial characteristics and other factors that could affect the public trading, acquisition or other values of the target companies in the selected transactions and Mirati in order to provide a context in which to consider the results of the quantitative analysis.

Using publicly available information obtained from SEC filings and other data sources as of the time of the announcement of the selected transactions, Centerview calculated, for each selected transaction, the transaction value (calculated as the offer value (determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units and performance stock units and other convertible securities), plus the book value of debt and certain liabilities less cash and cash equivalents and excluding any contingent consideration) implied for each target company based on the consideration payable in the applicable selected transaction, as a multiple of Wall Street research analyst consensus estimated four-year forward revenue multiples at the time of the transaction announcement (“4-Year Forward Revenue Multiple”).

Based on this analysis and other considerations that Centerview deemed relevant in its experience and professional judgment, related to, among other things, differences in the business, operational and/or financial conditions and prospects of Mirati and the companies included in the selected precedent transactions analysis, Centerview selected a reference range of 4-Year Forward Revenue Multiples of 5.0x to 9.5x derived from the selected transactions analysis. Centerview applied this reference range of 4-Year Forward Revenue Multiples to Mirati’s estimated four-year forward revenue excluding one-time items of $388 million as set forth in the Management Projections, and adding to it Mirati’s estimated net cash, as of December 31, 2023, of $861 million, provided by the management of Mirati, as set forth in the Internal Data, and divided the results of the foregoing calculations by the number of fully-diluted outstanding shares of our common stock (determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units and performance stock units) as of October 6, 2023 based on information provided by the management of Mirati and as set forth in the Internal Data. This analysis resulted in an implied per share equity value range for the shares of our common stock of approximately $34.05 to $54.90, rounded to the nearest $0.05. Centerview then compared this range to the Implied Consideration Value of $61.17 per Share to be paid to the holders of shares of our common stock (other than Excluded Shares) pursuant to the Merger Agreement and the CVR Agreement.

Centerview performed a discounted cash flow analysis of Mirati based on the Management Projections. 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 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 shares of our common stock by (a) discounting to present value, as of December 31, 2023, using discount rates ranging from 10.5% to 12.0% (based on Centerview’s analysis of Mirati’s weighted average cost of capital) and using a mid-year convention: (i) the forecasted risk-adjusted, after-tax unlevered free cash flows of Mirati over the period beginning on January 1, 2024 and ending on December 31, 2044, utilized by Centerview based on the Management Projections, (ii) an implied terminal value of Mirati, calculated by Centerview by assuming, as directed by Mirati’s management, that Mirati’s unlevered free cash flows would decline in perpetuity after December 31, 2044 at a rate of free cash flow decline of 80% year-over-year (with the exception of platform, overhead research and development, general and administrative cash flows, items for which a 0% perpetuity growth rate was assumed) and (iii) tax savings from usage of Mirati’s federal net operating losses of $1.1 billion as of December 31, 2022 and Mirati’s future losses, as set forth in the Management Projections, and (b) adding to the foregoing results Mirati’s estimated cash of $861 million as of December 31, 2023, and the net present value of the estimated cost of a $400 million net equity raise in 2024, as set forth in the Internal Data. Centerview divided the result of the foregoing calculations by the number of fully-diluted outstanding shares of our common stock (determined using the treasury stock method and taking into account outstanding in-the-money options, warrants, restricted stock units and performance stock units) as of October 6, 2023 and as set forth in the Internal Data. This resulted in an implied per share equity value range for the shares of our common stock of approximately $49.05 – $57.65, rounded to the nearest $0.05. Centerview then compared this

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

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 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 of Directors in its evaluation of the Transactions. Consequently, the analyses described above should not be viewed as determinative of the views of the Board of Directors or management of Mirati with respect to the Merger Consideration or as to whether the Board of Directors 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 Mirati and Parent and was approved by the Board of Directors. Centerview provided advice to Mirati during these negotiations. Centerview did not, however recommend any specific amount of consideration to Mirati 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, Centerview had not been engaged to provide financial advisory or other services to Mirati, and Centerview did not receive any compensation from Mirati during such period. In the two years prior to the date of its written opinion, Centerview had not been engaged to provide financial advisory or other services to Parent or Merger Sub, and Centerview did not receive any compensation from Parent during such period. Centerview may provide financial advisory and other services to or with respect to Mirati or Parent or their respective affiliates in the future, for which Centerview may receive compensation. Certain (i) of Centerview and its affiliates’ directors, officers, members and employees, or family members of

The Board of Directors selected Centerview as its financial advisor in connection with the Transactions based on Centerview’s strength and experience in the life sciences sector and expertise and qualifications in transactions of this nature. Centerview is an internationally recognized investment banking firm that has substantial experience in transactions similar to the Transactions.

In connection with Centerview’s services as the financial advisor to the Board of Directors, Mirati has agreed to pay Centerview an aggregate fee of approximately $53 million, $2.5 million of which was payable upon the rendering of Centerview’s opinion and the remainder of which is payable contingent upon consummation of the Transactions. In addition, Mirati 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.

While Mirati has from time to time provided limited full-year financial guidance to investors, Mirati’s management does not, as a matter of course, publicly disclose forecasts or internal projections as to future performance, or results of operations, earnings or other results, due to, among other things, the inherent difficulty of predicting financial performance for future periods and the likelihood that the underlying assumptions and estimates may not be realized.

In connection with the evaluation of the proposed transaction with BMS and the other strategic alternatives considered by the Board of Directors, in late August and early September 2023 Mirati’s senior management prepared certain non-public, unaudited financial projections for fiscal years 2023 through 2044 (which we refer to as the “Management Projections”). The Management Projections were prepared based on Mirati’s continued operation as a stand-alone company and do not take into account the Merger, including the effect of any business or strategic decision or action that has been or will be taken as a result of the execution of the Merger Agreement.

Prior to the preparation of the Management Projections, in June 2023, Mirati’s senior management prepared certain non-public, unaudited, prospective revenue information for fiscal years 2023-2040 (which we refer to as the “June 2023 Management Revenue Projections”) in connection with the Board of Directors’ evaluation of the equity financing completed by Mirati on August 11, 2023. The assumptions in the Management Projections differ from the assumptions in the June 2023 Management Revenue Projections due to changes affecting Mirati and its products and programs.

Additionally, the Board of Directors reviewed certain non-public, unaudited, prospective revenue information prepared by Mirati’s senior management for fiscal years 2023-2038 during a regularly scheduled quarterly meeting of the Board of Directors on September 28, 2023 (which we refer to as the “September 2023 Management Revenue Projections”) in connection with the Board of Directors’ review of potential scenarios for Mirati continuing as a stand-alone company. Compared to the Management Projections, the September 2023 Management Revenue Projections assumed a narrower commercialization model for certain global markets and reflected management’s more conservative assumptions for patient growth rate and treatment rate in certain markets.

The Management Projections were presented to the Board of Directors in connection with its consideration of the Merger, and were provided to Centerview and, at the instruction of the Board of Directors, were relied upon by Centerview in connection with rendering its opinion to the Board of Directors and performing the related financial analyses as described in the section of this proxy statement captioned “—Opinion of Mirati’s Financial Advisor – Centerview Partners LLC” and were the only financial projections with respect to Mirati used by Centerview in performing such financial analyses.

Mirati is summarizing the Management Projections, the June 2023 Management Revenue Projections and the September 2023 Management Revenue Projections (which we refer to collectively as the “Projections”) in this proxy statement to provide our stockholders with access to certain non-public, unaudited, risk-adjusted prospective financial information that was prepared for the Board of Directors for the purposes described above.

The Projections, while necessarily presented with numerical specificity, were based on numerous variables and financial, operating and commercial assumptions, developed solely using the information available to Mirati’s management at the time, that were inherently uncertain and many of which were beyond Mirati’s control. Important factors that may affect actual results and cause the Projections not to be achieved include general economic conditions, regulatory conditions, financial market conditions, Mirati’s ability to achieve forecasted sales of KRAZATI and other pipeline products, accuracy of certain accounting assumptions, changes in actual or projected cash flows, competitive pressures, changes in tax laws or accounting treatment and other risk factors described in Mirati’s Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and its subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The Projections also reflect assumptions as to certain business decisions 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. The Projections cover multiple years, and such information by its nature becomes less reliable with each successive year.

Neither Mirati nor any of its affiliates, advisors, officers, directors or representatives has made or makes any representation or warranty to any holders of shares of our common stock or other person regarding the ultimate performance of Mirati compared to the information contained in the Projections or that the Projections will be achieved. Mirati has made no representation to BMS or Merger Sub, in the Merger Agreement or otherwise, concerning the Projections. The Projections are subjective in many respects and are thus subject to interpretation. Please also refer to the section of this proxy statement captioned “Forward-Looking Statements.”

The Projections were not prepared with a view toward compliance with published guidelines of the SEC, the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of financial forecasts, or U.S. generally accepted accounting principles (“GAAP”). Non-GAAP financial measures should not be considered in isolation from, or as a substitute for, financial information presented in compliance with GAAP, and non-GAAP financial measures as used by Mirati may not be comparable to similarly titled amounts used by other companies. The financial measures included in the Projections are not subject to SEC rules regarding disclosures of non-GAAP financial measures, which would otherwise require a reconciliation of a non-GAAP financial measure to a GAAP financial measure. Reconciliations of non-GAAP financial measures were not provided to or relied upon by the Board of Directors or Centerview. In addition, the Projections were not prepared with the assistance of, or reviewed, compiled or examined by, independent accountants. The Projections are not being included in this proxy statement to influence any stockholder’s decision on how to vote with respect to the Merger Proposal, but instead are being included because the Management Projections were provided to the Board of Directors and to Centerview to evaluate the Transactions and the June 2023 Management Revenue Projections were provided to the Board of Directors during the period from June to early August 2023 to evaluate a proposed equity financing. Mirati did not provide the Projections to Parent. The Projections may differ from publicly available analyst estimates, and the Projections do not take into account any events or circumstances after the date they were prepared, including the announcement of the Merger.

At the direction of Mirati’s management, Centerview calculated, solely based on the Management Projections, the unlevered free cash flows for the fiscal years 2024 through 2044, which were approved by the Board of Directors for use by Centerview in connection with the rendering its opinion to the Board of Directors and in performing the related financial analyses as described in the section of this proxy statement captioned “—Opinion of Mirati’s Financial Advisor - Centerview Partners LLC.” The unlevered free cash flows used by Centerview in connection with its opinion to the Board of Directors, were calculated as EBIT (earnings before interest expenses and taxes) minus tax expense plus depreciation and amortization minus capital expenditures and minus changes in net working capital. The values presented in the tables below do not take into account the effect of net operating loss usages or the cost of future equity raises and assume a tax rate of 21%.

When considering the recommendation of the Board of Directors that you vote to approve the Merger Proposal, you should be aware that our directors and executive officers may have interests in the Merger that are different from, or in addition to, the interests of our stockholders generally, as more fully described below. The Board of Directors was aware of and considered these interests to the extent that they existed at the time, among other matters, in evaluating, negotiating and approving the Merger Agreement and the Merger and recommending that the Merger Agreement be adopted by Mirati’s stockholders.

Also mentioned in the discussion below are three former executives who are no longer employed by us but who were named executive officers for purposes of the Definitive Proxy Statement on Schedule 14A, filed by Mirati on April 6, 2023:

Mirati’s directors and executive officers who own shares of our common stock will receive in the Transactions the same Merger Consideration, on the same terms and conditions, as the other stockholders of Mirati, as described in the section of this proxy statement captioned “— Merger Consideration.”

The following table sets forth the number of issued and outstanding shares of our common stock beneficially owned as of October 18, 2023 by each of Mirati’s directors and current and former executive officers as described above. For purposes of the table below, the number of shares of our common stock excludes (i) shares of our common stock underlying Company Options and (ii) shares of our common stock that are subject to outstanding and unvested Company RSUs (including performance-vesting Company RSUs). The following table also sets forth the aggregate Closing Consideration and potential CVR payment that would be payable for such shares if the CVR Product Milestone is achieved within the time period required by the CVR Agreement. The amount of potential CVR Payment assumes that each CVR will be paid at the value of $12.00 per CVR. As explained herein, the CVR payment is conditioned on the achievement of the milestone set forth in the CVR Agreement, which may or may not be achieved within the allotted time frame.

The Merger Agreement provides that at the Effective Time, each Company Option that is then outstanding and unexercised (whether or not vested) and which has a per share exercise price that is less than the Closing Consideration (each, an “In the Money Option”) will be cancelled and converted into the right to receive a cash payment equal to (i) the excess of (a) the Closing Consideration over (b) the exercise price per share of such In the Money Option, multiplied by (ii) the total number of shares of our common stock subject to such In the Money Option, plus one CVR for each share of our common stock subject to such In the Money Option.

If and only if the Milestone Payments are made in respect of the CVRs, each Company Option which is not an In the Money Option but has a per share exercise price less than the sum of the Closing Consideration and the potential amount payable with respect to one CVR (each, an “Eligible Option”) will be entitled to receive a cash payment equal to the amount by which the sum of the Closing Consideration and the potential amount payable with respect to one CVR exceeds the per share exercise price of such Eligible Option, multiplied by the number of shares of our common stock subject to such Eligible Option.

Any Company Option not described in the preceding two paragraphs that is then outstanding and unexercised (whether or not vested) will be cancelled at the Effective Time without consideration.

The following table sets forth, for each of Mirati’s directors and current and former executive officers as described above, (i) the number of vested and unvested In the Money Options that were held as of October 18, 2023; (ii) the Closing Consideration payable for these In the Money Options based solely on the $58.00 Closing Consideration (excluding any potential value deriving from a contingent CVR payment); (iii) the potential CVR payments that would be payable for these In the Money Options if the CVR Product Milestone is achieved within the time period required by the CVR Agreement; (iv) the number of Eligible Options held as of October 18, 2023; and (v) the amounts payable with respect to such Eligible Options if the CVR Product Milestone is achieved within the time period required by the CVR Agreement. The amount of potential CVR payment assumes that each CVR will be paid at the value of $12.00 per CVR. As explained herein, the CVR payment is conditioned on the achievement of the milestone set forth in the CVR Agreement, which may or may not be achieved.

In addition, at the Effective Time, each then outstanding Company RSU, including, to the extent provided pursuant to their terms, performance-vesting Company RSUs, will be cancelled and the holder thereof will be entitled to receive a cash payment equal to the product of (i) the Closing Consideration and (ii) the number of shares of our common stock subject to such Company RSU, plus one CVR for each share of our common stock subject to the Company RSU. Performance-vesting Company RSUs which do not vest in connection with the Merger in accordance with their terms will be cancelled (also in accordance with their terms) for no consideration at the Effective Time.

If the Effective Time does not occur prior to January 10, 2024, and the Company grants in 2024 time-based vesting Company RSUs (the “2024 Awards”), such awards will convert at the Effective Time into a cash award equal to the product of the number of Company RSUs subject to the 2024 Award immediately prior to the Effective Time and the last trading price of our common stock before the Effective Time as reported by Nasdaq (the “Converted Cash Award”). The Converted Cash Award will be subject to the same terms and conditions (including vesting) applicable to the 2024 Award. No 2024 Awards will be eligible to receive any CVRs. No such awards have been promised or granted as of the date hereof.

Certain of our officers, including our currently employed named executive officers, receive severance benefits under Mirati’s Executive Severance Plan. Under the Executive Severance Plan, in the event of a termination without “cause” or resignation for “good reason” (as each is defined in the Executive Severance Plan, an “Involuntary Termination”), in each case, that occurs three months prior to or within twenty four

These severance benefits are subject to the execution and effectiveness of a waiver and release of claims in favor of us. Potential severance payments to Drs. Baum, Christensen and Sandler and Mr. Ondrey are summarized in the section of this proxy statement captioned “— Golden Parachute Compensation.” Potential severance payments to Messrs. Hickey and Moriarty, as a group, are approximately $2,363,678 in the aggregate.

In addition, Mr. Ondrey is entitled to a cash retention payment in the amount of $300,000 as well as $300,000 in performance-based Company RSUs, that will vest and be payable on the earlier of 90 days following the commencement of the employment of a permanent Chief Financial Officer or an involuntary termination of employment not for cause as defined in the applicable agreement.

Mr. Meek’s employment with Mirati terminated in August 2023 and he is not entitled to any severance benefits in connection with the Transactions except for the supplemental payment under the separation agreement entered into between Mirati and Mr. Meek, as further described below in the section of this proxy statement captioned “— Golden Parachute Compensation.”

Ms. Stelzer will not receive any severance benefits based on or otherwise related to the Transactions other than the acceleration of equity awards which were scheduled to vest during her currently ongoing consulting period. All outstanding equity awards that were eligible to vest following the end of the consulting term were cancelled and forfeited for no consideration.

In connection with the Transactions, the Board of Directors approved that Mirati may provide reimbursement in an aggregate amount not to exceed $10,000,000 for excise taxes incurred under Section 4999 of the Code in connection with the Transactions to affected executive officers, so that on a net after-tax basis such executive officers would be in the same position as if no such excise tax had applied to them. The actual amount of the excise tax reimbursement for each named executive officer, if any, will not be determinable until after the consummation of the Transactions. The estimated value of the excise tax reimbursement payment for Dr. Sandler is set forth below in the section of this proxy statement captioned “— Golden Parachute Compensation.” The estimated value of the excise tax reimbursement payments for Mr. Hickey and Mr. Moriarty are $2,248,710 and $1,899,273, respectively.

In connection with the Transactions, Mirati may establish a cash retention program for eligible employees, including the Mirati’s Chief Commercial Officer, Mr. Ben Hickey. Payment to Mr. Hickey under the cash retention program, if any, may not exceed $900,000. Allocations under the cash retention program will be determined at the discretion of Mirati’s Chief Executive Officer after consultation with Parent. Awards made under the cash retention program may become payable on the Closing Date. As of the date of this proxy statement, no awards under the cash retention program have been made to any executive officer of Mirati.

This section sets forth the information required by Item 402(t) of Regulation S-K regarding the compensation that is based on or otherwise related to the transactions contemplated by the Merger Agreement for each of Mirati’s executive officers who were designated as “named executive officers” in Mirati’s definitive proxy statement for our 2023 annual meeting of stockholders filed with the SEC on April 6, 2023 as well as the current Principal Financial Officer. This compensation is referred to as “golden parachute” compensation by the

The table below sets forth, for the purposes of this golden parachute disclosure, the amount of payments and benefits that each of Mirati’s named executive officers would receive, assuming that (1) the closing occurred on October 18, 2023 (which is the assumed closing date solely for purposes of this golden parachute compensation disclosure); (2) each of Mirati’s named executive officers is employed or providing services to Mirati at the closing and experiences a qualifying termination of employment immediately following the closing; (3) no named executive officer enters into any new agreement or becomes entitled to, prior to the closing, additional compensation or benefits related to the transactions contemplated by the Merger Agreement; (4) the performance vesting conditions applicable to any Mirati performance awards are deemed achieved at the target level of performance; (5) each named executive officer has properly executed any required releases and complied with all requirements (including any applicable restrictive covenants) necessary in order to receive all payments and benefits; and (6) the value per share of Mirati common stock on the completion of the transactions contemplated by the Merger Agreement is $70 (i.e., the sum of the $58 Closing Consideration plus the $12 potential amount payable with respect to one CVR). Some of the assumptions used in the table below are based upon information not currently available and, as a result, the actual amounts to be received by any of the named executive officers below may materially differ from the amounts set forth below. The actual amounts payable to Mirati named executive officers will depend on whether, among other things, the named executive officer experiences a qualifying termination, the date of such termination (if any) and the terms of the plans or agreements in effect at such time, and accordingly may differ materially from the amounts set forth below.