We invite you to join us for the Exelixis 2023 Annual Meeting of Stockholders on May 31, 2023, beginning at 9:00 a.m., Pacific Time, at Exelixis’ offices, 1851 Harbor Bay Parkway, Alameda, CA 94502. Please see the following notice of our Annual Meeting for details of the business to be conducted, as well as information regarding how and when to vote.

In 2022, Exelixis again made significant progress on its mission to help cancer patients recover stronger and live longer and achieved its sixth year of annual profitability. Fueled by revenues from the growing, global CABOMETYX^® (cabozantinib) oncology franchise, the company advanced its clinical pipeline, expanded its discovery and in-licensing activities, and built out its infrastructure and team. As a result, Exelixis is well positioned to drive further innovation with the potential to improve the standard of care for multiple forms of cancer. We believe this type of transformative oncology innovation is critical to delivering sustained value creation. Exelixis’ 2022 accomplishments include:

2022 also marked the launch of the company’s first Corporate Values & Sustainability Report, which encapsulates Exelixis’ sustainable business practices and commitment to our four core environmental, social and governance (ESG) themes: Access to innovative and safe cancer medicines; Community engagement and advocacy; Our people and culture; and Environmental management. You can read the full Report on the Corporate Values & Sustainability page under the Impact heading on www.exelixis.com. The document is a direct reflection of Exelixis’ culture and the values the team strives to live by every day—to Be Exceptional, Excel for Patients and Exceed Together.

TO BE HELD ON MAY 31, 2023

NOTICE IS HEREBY GIVEN that the 2023 Annual Meeting of Stockholders (Annual Meeting) of Exelixis, Inc., a Delaware corporation (Exelixis), will be held on Wednesday, May 31, 2023, at 9:00 a.m., Pacific Time, at Exelixis’ offices, 1851 Harbor Bay Parkway, Alameda, CA 94502. Only stockholders of record at the close of business on April 3, 2023 are entitled to vote at the meeting. If you plan to attend the meeting in person, please note the admission procedures described under “How can I attend the Annual Meeting?” on page 1 of the Proxy Statement.

Please note that Farallon Capital Management, L.L.C. (Farallon) has (i) formed a “group” within the meaning Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (Exchange Act) with Caligan Partners LP (Caligan) for the purpose of soliciting proxies in connection with the Annual Meeting (the Farallon-Caligan Group) and (ii) notified Exelixis of its intent to nominate a slate of three candidates (the Farallon-Caligan nominees), including Tomas J. Heyman and Robert “Bob” Oliver, Jr., for election as directors at the Annual Meeting in partial opposition to the candidates nominated by the Exelixis Board of Directors. You may receive solicitation materials from the Farallon-Caligan Group, including proxy statements and proxy cards. Exelixis is not responsible for the accuracy of any information provided by or relating to the Farallon-Caligan Group or their nominees contained in solicitation materials filed or disseminated by or on behalf of the Farallon-Caligan Group or any other statements the Farallon-Caligan Group or its representatives may make.

››    Maria C. Freire

››    Alan M. Garber

››    Michael M. Morrissey

››    Stelios Papadopoulos

››    George Poste

››    Julie Anne Smith

››    Lance Willsey

››    Jacqueline Wright

››    Jack L. Wyszomierski

››       “FOR” the election of the Farallon-Caligan nominees recommended by the Exelixis Board of Directors;

››    Tomas J. Heyman

››    Robert “Bob” Oliver, Jr.

››       “WITHHOLD” on the election of the non-recommended Farallon-Caligan nominee.

The Exelixis Board of Directors strongly urges you to discard and NOT use any proxy card sent to you by the Farallon-Caligan Group. If you have previously submitted a proxy card sent to you by the Farallon-Caligan Group, you can revoke that proxy and vote for the nominees recommended by the Exelixis Board of Directors and on the other matters to be voted on at the meeting by using the enclosed GOLD proxy card. Only your latest validly executed proxy will count, and any proxy may be revoked at any time prior to its exercise at the Annual Meeting as described in the accompanying proxy statement.

PLEASE NOTE THAT THIS YEAR, YOUR PROXY CARD LOOKS DIFFERENT. IT HAS MORE NAMES ON IT THAN THERE ARE SEATS UP FOR ELECTION, UNDER NEW REQUIREMENTS CALLED A “UNIVERSAL PROXY CARD.” THIS MEANS EXELIXIS’ PROXY CARD IS REQUIRED TO LIST THE FARALLON-CALIGAN NOMINEES IN ADDITION TO EXELIXIS’ NOMINEES. PLEASE MARK YOUR CARD CAREFULLY AND ONLY VOTE “FOR” THE NOMINEES AND PROPOSALS RECOMMENDED BY YOUR BOARD OF DIRECTORS AND VOTE “WITHHOLD” ON THE NON-RECOMMENDED FARALLON-CALIGAN NOMINEE.

The record date for the Annual Meeting is April 3, 2023. Only stockholders of record at the close of business on that date may vote at the meeting or any postponement or adjournment thereof.

May 1, 2023

May 31, 2023

We intend to mail the Proxy Statement and proxy card relating to the Annual Meeting on or about May 1, 2023 to all stockholders of record entitled to vote at the Annual Meeting.

We have made these materials available to you on the Internet or, upon your request, have delivered printed versions of these materials to you by mail because the Board of Directors (the Board), of Exelixis, Inc. (sometimes referred to as “we,” “us,” the “company” or “Exelixis”) is soliciting your proxy to vote at the 2023 Annual Meeting of Stockholders (Annual Meeting), including at any adjournments or postponements of the meeting. The Annual Meeting will be held on Wednesday, May 31, 2023, at 9:00 a.m., Pacific Time, at Exelixis’ offices, 1851 Harbor Bay Parkway, Alameda, CA 94502. We invite you to attend the Annual Meeting to vote on the proposals described in this Proxy Statement. However, you do not need to attend the Annual Meeting to vote your shares. Instead, you may simply complete, sign and return a proxy card, or follow the instructions below and set forth on the enclosed GOLD proxy card or voting instruction form to vote your shares on the Internet.

We intend to send or make available these materials to stockholders on May 1, 2023.

Admission to the meeting is restricted to stockholders and/or their designated representatives. Please note that beneficial holders who want to attend and also vote in person at the Annual Meeting will need to obtain a legal proxy from the organization that holds their shares giving the right to vote their shares in person at the Annual Meeting and to present it with their ballot during the meeting.

Where can I find more information or receive more than one set of proxy materials from the company?

If you receive more than one set of proxy materials from Exelixis, some of your shares of Common Stock may be registered differently or held in a different account. You should vote the shares in each of your accounts by one of the methods described herein. If you mail proxy cards, please sign, date and return each GOLD proxy card to guarantee that all your shares of Common Stock are voted.

Only stockholders of record at the close of business on April 3, 2023, (the Record Date) will be entitled to vote at the Annual Meeting. On the Record Date, there were 324,985,377 shares of common stock outstanding and entitled to vote.

If on April 3, 2023, your shares were registered directly in your name with our transfer agent, Computershare Trust Company, N.A., then you are a stockholder of record. As a stockholder of record, you may vote at the Annual Meeting or vote by proxy. Whether or not you plan to attend the Annual Meeting, we urge you to vote by proxy on the Internet as instructed below, or complete and mail the proxy card if you received printed materials.

If on April 3, 2023, your shares were held in an account at a brokerage firm, bank, dealer or other similar organization, then you are the beneficial owner of shares held in “street name,” and these proxy materials are being forwarded to you by that organization. The organization holding your shares is considered to be the stockholder of record for purposes of voting at the Annual Meeting. As a beneficial owner, you have the right to direct your broker, bank or other stockholder of record regarding how to vote the shares in your account, and we invite you to attend the Annual Meeting. Beneficial holders who want to attend and also vote in person at the Annual Meeting will need to obtain a legal proxy from the organization that holds their shares giving the right to vote their shares; this legal proxy will allow for voting shares in person at the Annual Meeting and must be presented along with the ballot during the meeting.

On each matter to be voted upon, you have one vote for each share of common stock you own as of the Record Date, April 3, 2023.

However, because the Farallon-Caligan Group has indicated its intention to deliver proxy materials in opposition to our board of directors to your broker for forwarding to you on their behalf, with respect to accounts to which the Farallon-Caligan Group mails its proxy materials, brokers will not have discretion to vote on “routine matters,” including Proposal 2. As a result, if you do not instruct your broker on how to vote your shares regarding the election of directors, the ratification of Ernest & Young LLP as our independent registered public accounting firm for fiscal year 2023 (Proposal 2), the advisory vote on the resolution to approve executive compensation (Proposal 3) or the advisory vote to approve the frequency of the company’s executive compensation advisory vote (Proposal 4), then your shares may not be voted on these matters. We urge you to instruct your broker about how you wish your shares to be voted.

What should I do if I receive a white proxy card or other proxy materials from or on behalf of the Farallon-Caligan Group?

The Farallon-Caligan Group has filed proxy materials with the SEC to solicit our stockholders in support of Farallon’s purported nominees and proposals. The Board strongly urges you to disregard any materials sent to you by or on behalf of the Farallon-Caligan Group, and to NOT sign or return any white proxy cards sent to you by or on behalf of the Farallon-Caligan Group, or even to “withhold” from Farallon’s purported nominees and proposals or vote “for” the nominees recommended by the Board on the Farallon-Caligan Group’s white proxy card. The company is not responsible for the accuracy of any information provided by the Farallon-Caligan Group in solicitation materials filed or disseminated by or on behalf of the Farallon-Caligan Group or any other statements that the Farallon-Caligan Group may make.

If you have already voted using a white proxy card sent to you by the Farallon-Caligan Group, you can revoke it by following the instructions on the enclosed GOLD proxy card to vote, by completing and returning the enclosed GOLD proxy card or by voting at the Annual Meeting. Any vote on a white proxy card will revoke any GOLD proxy card that you may have previously submitted. Only your latest dated proxy will count, and any proxy may be revoked at any time prior to its exercise at the Annual Meeting.

The proxies being solicited hereby are being solicited by the Board. Exelixis will bear the entire cost of soliciting proxies in the enclosed form, including the preparation, printing and mailing of the Notice of Annual Meeting, the Proxy Statement, the GOLD proxy card and any additional information furnished to stockholders. We have engaged Innisfree M&A Incorporated, located at 501 Madison Avenue, 20th Floor, New York, NY 10022 (Innisfree), to assist in the solicitation of proxies from shareholders for a fee of up to $875,000 plus reimbursement of customary out-of-pocket expenses. Innisfree expects that approximately 40 of its employees will assist in the solicitation. The expense incurred by Exelixis to date in furtherance of, or in connection with, the solicitation is approximately $8.2 million. Exelixis anticipates that its total expenditures will be approximately $13.7 million. The actual amount could be higher or lower depending on the facts and circumstances arising in connection with this solicitation. Copies of solicitation materials will be furnished to banks, brokerage houses, fiduciaries and custodians holding in their names shares of our common stock beneficially owned by others to forward to such beneficial owners. We may reimburse persons representing beneficial owners of our common stock for their costs of forwarding solicitation materials to such beneficial owners. Original solicitation of proxies by mail may be supplemented by telephone, telegram or personal solicitation by our directors, officers or other regular employees. No additional compensation will be paid to directors, officers or other regular employees for such services.

Other than persons described in this Proxy Statement, no general class of employee of Exelixis will be employed to solicit stockholders in connection with this proxy solicitation. However, in the course of their regular duties, our employees, officers and directors may be asked to perform clerical or ministerial tasks in furtherance of the solicitation. None of these individuals will receive any additional or special compensation for doing this, but they may be reimbursed for reasonable out-of-pocket expenses. We will, upon request, reimburse brokerage firms and others for their reasonable expenses in forwarding solicitation material to the beneficial owners of stock. Annex A sets forth information relating to certain of Exelixis’ directors, director nominees and certain executive officers and employees who are considered “participants” in Exelixis’ solicitation under the rules of the SEC by reason of their position as directors of the company or because they may be soliciting proxies on Exelixis’ behalf.

To be considered for inclusion in the 2024 proxy materials, your proposal must be submitted in writing by January 2, 2024, to Exelixis’ Secretary at Exelixis, Inc., 1851 Harbor Bay Parkway, Alameda, California 94502, and you must comply with all applicable requirements of Rule 14a-8 promulgated under the Exchange Act. However, if our 2024 Annual Meeting of Stockholders is held before May 1, 2024, or after June 30, 2024, then the deadline will be a reasonable time prior to the time that we make our proxy materials available to our stockholders, either online or in printed form.

If you wish to submit a proposal or nominate a director at the 2024 Annual Meeting of Stockholders, but you are not requesting that your proposal or nomination be included in next year’s proxy materials, you must submit your proposal in writing, in the manner set forth in our Bylaws, to Exelixis’ Secretary at Exelixis, Inc., 1851 Harbor Bay Parkway, Alameda, California 94502, to be received no earlier than the close of business on March 2, 2024, and no later than the close of business on April 1, 2024. However, if our 2024 Annual Meeting of Stockholders is held before May 1, 2024, or after June 30, 2024, then you must notify Exelixis’ Secretary, in writing, not earlier than the close of business on the 90th day prior to the date of the 2024 Annual Meeting of Stockholders and not later than the close of business on the later of (i) the 60th day prior to the date of the 2024 Annual Meeting of Stockholders or (ii) if we publicly announce the date of the 2024 Annual Meeting of Stockholders fewer than 70 days prior to the date of the 2024 Annual Meeting of Stockholders, the 10th day following the day that we first make such public announcement of the date of the 2024 Annual Meeting of Stockholders. In addition,

This Proxy Statement contains forward-looking statements, including, without limitation, statements related to: Exelixis’ plans for future growth of its pipeline and infrastructure, including at the Alameda campus and East Coast expansion; Exelixis’ commitment to fostering a culture of inclusion and belonging; Exelixis’ belief that its 2022 accomplishments have created the potential for additional eligible cancer patient communities to benefit from CABOMETYX and the investigational products in Exelixis’ growing pipeline, while also putting the company in a solid position to deliver long-term revenue and earnings growth; Exelixis’ expectations that its employees and partners will commit to the highest standards of ethical behavior and maintain values and principles that reflect both global awareness and sustainability; Exelixis’ dedication of financial resources to offer patients high-quality cancer treatments and commitment to providing patients with access to Exelixis medicines; Exelixis’ strategies for quality monitoring and compliance in developing its products; Exelixis’ potential to attain future environmental stability; Exelixis’ ongoing efforts towards the achievement of key priorities and anticipated milestones for 2023 and beyond; Exelixis’ ability to execute on potential future strategic initiatives; Exelixis’ plans for the continued buildout of its Digital Transformation function to further enhance its information technology infrastructure; potential shifts in healthcare regulations applicable to Exelixis’ business; Exelixis’ plans for continued development of cabozantinib, zanzalintinib (formerly XL092), XB002, XL102 and other current and future development candidates, as well for the evaluation and development of new INDs and collaboration management; and other statements that are not historical fact. Any statements that refer to expectations, projections or other characterizations of future events or circumstances are forward-looking statements and are based upon Exelixis’ current plans, assumptions, beliefs, expectations, estimates and projections. Forward-looking statements involve risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in the forward-looking statements as a result of these risks and uncertainties, which include, without limitation: the degree of market acceptance of CABOMETYX and other Exelixis products in the indications for which they are approved and in the territories where they are approved, and Exelixis and its partners’ ability to obtain or maintain coverage and reimbursement for these products; the effectiveness of CABOMETYX and other Exelixis products in comparison to competing products; the level of costs associated with Exelixis’ commercialization, research and development, in-licensing or acquisition of product candidates, and other activities; Exelixis’ ability to maintain and scale adequate sales, marketing, market access and product distribution capabilities for its products or to enter into and maintain agreements with third parties to do so; the availability of data at the referenced times; the potential failure of cabozantinib, zanzalintinib and other Exelixis product candidates, both alone and in combination with other therapies, to demonstrate safety and/or efficacy in future clinical testing; uncertainties inherent in the drug discovery and product development process; Exelixis’ dependence on its relationships with its collaboration partners, including their pursuit of regulatory approvals for partnered compounds in new indications, their adherence to their obligations under relevant collaboration agreements and the level of their investment in the resources necessary to complete clinical trials or successfully commercialize partnered compounds in the territories where they are approved; complexities and the unpredictability of regulatory review and approval processes in the U.S. and elsewhere; Exelixis’ continuing compliance with applicable legal and regulatory requirements; unexpected concerns that may arise as a result of the occurrence of adverse safety events or additional data analyses of clinical trials evaluating cabozantinib, zanzalintinib and other Exelixis products; Exelixis’ dependence on third-party vendors for the development, manufacture and supply of its products and product candidates; Exelixis’ ability to protect its intellectual property rights; market competition, including the potential for competitors to obtain approval for generic versions of Exelixis’ marketed products; changes in economic and business conditions; and other factors discussed under the caption “Risk Factors” in Exelixis’ Annual Report on Form 10-K filed with the SEC on February 7, 2023, and in Exelixis’ future filings with the SEC. All forward-looking statements in this Proxy Statement are based on information available to Exelixis as of the date of this Proxy Statement, and Exelixis undertakes no obligation to update or revise any forward-looking statements contained herein, except as required by law.

The Board evaluates, with senior management of Exelixis, the company’s strategy, capital allocation framework and proposals, research and development (R&D) plans and operating expenses goals on an ongoing basis. This evaluation takes into account the perspectives of the company’s shareholders, whose views are actively and regularly requested and received by the company. Under the direction of the Board and senior management, the company annually undertakes an expansive corporate planning process to drive alignment on the actions needed to implement the company’s strategies, including its capital expenditures, operating expenses and R&D plans.

Throughout these processes and as part of its ongoing shareholder engagement, members of the company’s senior management team met with representatives of Farallon on at least 52 occasions since Farallon’s most recent company investment position was made known to Exelixis in 2018. During these meetings with representatives of Farallon, and in a manner consistent with Exelixis’ ongoing engagement with its other shareholders, representatives of Exelixis discussed Exelixis’ R&D plans and results, recent data presentations, competitive developments, go-forward strategy, capital allocation framework and operating expenses goals.

The summary below details the significant contacts between Exelixis and Farallon, as well as associated entities supporting Farallon’s efforts, in connection with Farallon’s solicitation since January 26, 2023.

On January 26, 2023, pursuant to applicable U.S. antitrust laws, Farallon provided a letter to Exelixis stating its intention to file notifications under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the HSR Act), to enable certain investment funds affiliated with Farallon to acquire voting securities of Exelixis. On February 22, 2023, the Federal Trade Commission granted early termination of the waiting periods applicable under the HSR Act with respect to those notifications.

On February 16, 2023, the Board received a letter from Farallon (the February 16 Letter), in which Farallon criticized the company’s performance as “a result of the lack of focus in its R&D pipeline and inefficient capital allocation practices.” In the February 16 Letter, Farallon requested a meeting with the Board to discuss the matters raised therein. Following receipt of the February 16 Letter, Dr. Michael Morrissey, Exelixis’ Chief Executive Officer, contacted representatives of Farallon to arrange that meeting.

On March 8, 2023, representatives of Exelixis, including Drs. Papadopoulos, Chairman of the Board; Willsey, Independent Director; and Morrissey met in person with representatives of Farallon, including Philip D. Dreyfuss and Drs. Chris Devine and Thomas Roberts Jr. (the March 8 Meeting). Drs. Papadopoulos and Willsey had travelled from the east coast for this meeting, at which the parties discussed, among other things, Exelixis’ capital allocation framework, including its R&D strategy, tactics and processes, and the composition of the Board. During the meeting, Dr. Papadopoulos suggested that, subject to an appropriate confidentiality agreement, Exelixis would be willing to provide Farallon with certain non-public information regarding the company’s business strategy and capital allocation plans to help Farallon better understand those strategies and plans and potentially ameliorate Farallon’s mistaken concerns. The participants also discussed the views of each party regarding the trading price of Exelixis’ common shares, with Exelixis’ representatives noting their view that the company’s trading price had been substantially range bound since 2019 due to uncertainty associated with the ultimate outcome of the ongoing cabozantinib Abbreviated New Drug Application (ANDA) litigation. Farallon’s representatives responded by saying that, to the contrary, Farallon believed Exelixis’ trading price reflected Exelixis’ excessive R&D budget and unwise choice of projects as well as Exelixis’ failure to return capital to shareholders. The Farallon representatives then stated their view that the Board should enact immediate, drastic cuts to Exelixis’ R&D spend and form a Board committee to focus on capital allocation going forward, with the goal of rationalizing and focusing R&D spend, and significantly increase return of capital to shareholders via share repurchases. In addition, the Farallon representatives stated their view that four new, independent members should be appointed to the Board—including four selected by Farallon (Tomas Heyman, Hugh Rienhoff, David Johnson, and Robert Oliver, Jr.)—in place of four existing directors, and that those new Board members should be designated to serve on the new strategy and capital allocation committee as well as the existing R&D Committee of the Board (the R&D

Committee). The Farallon representatives also asserted that Exelixis needed to engage in increased communications with investors with respect to the company’s R&D spending and capital allocation priorities and practices and establish a one-year moratorium on open market equity sales by insiders. At that point, Dr. Papadopoulos volunteered that in the interest of goodwill he was prepared to sign a one-year lock up for his personal shares that had been largely acquired through open market purchases over the years.

On March 9, 2023, Drs. Papadopoulos, Morrissey and Willsey received a follow-up letter from Farallon (the March 9 Letter). The March 9 Letter largely memorialized Farallon’s assertions from the March 8 Meeting: it stated that the Board should form a committee to focus on strategy and capital allocation, with the goal of proposing how to significantly rationalize and focus R&D spend and meaningfully return capital to shareholders via share repurchases; it further suggested that the Board should appoint four new, independent members selected by Farallon to the Board, Mr. Tomas Heyman, Mr. David Johnson, Mr. Robert Oliver, Jr., and Dr. Hugh Rienhoff, (who subsequently withdrew from consideration), in place of four existing directors, and designate such new Board members to serve on the new committee, as well as the R&D Committee; and finally, that the Board should communicate with investors with respect to Exelixis’ R&D spending and capital allocation priorities and practices and establish a one-year moratorium on open market equity sales by insiders.

On March 13, 2023, the Board held an update call, with representatives from Exelixis’ senior management and from Paul, Weiss, Rifkind, Wharton & Garrison LLP (Paul Weiss), the company’s outside legal counsel, in attendance. During this call, members of the Board discussed Farallon’s requests as described in the March 9 Letter. Following this March 13 Board call, Drs. Papadopoulos and Morrissey had additional conversations with various Board members regarding the March 8 Meeting with Farallon, the March 9 Letter and Farallon’s request for representation on the Board.

On March 16, 2023, the Board held a meeting, with members of the company’s senior management and representatives from Paul Weiss in attendance. At this meeting, senior management presented, and the Board considered, information concerning the advisability and prudent size and duration of a share repurchase program. Such a program had been under consideration and discussed by the Board over the past two years and so, in consideration of those prior discussions and the new information presented, the Board approved a $550 million share repurchase program. The Board also noted during its meeting that, as a means to return capital to shareholders, the share repurchase program would address one of the concerns raised by Farallon in its March 9 Letter.

On March 17, 2023, Drs. Papadopoulos, Morrissey and Willsey from Exelixis, and Mr. Dreyfuss and Drs. Devine and Roberts from Farallon met at the request of Farallon (the March 17 Meeting) to discuss the March 9 Letter. During the March 17 Meeting, Dr. Papadopoulos reiterated Exelixis’ offer to provide non-public information to Farallon to help Farallon better understand Exelixis’ business and capital allocation policy, including the company’s R&D strategy, tactics and processes, subject to execution of an appropriate confidentiality agreement. Farallon’s representatives responded that Farallon would consider entering into such a confidentiality agreement. During the March 17 Meeting, Farallon’s representatives also identified to Exelixis’ representatives a revised slate of potential candidates for the Board, this time naming five individuals—Mr. Heyman, Mr. Johnson, and Mr. Oliver, Jr. as well as Dr. Rienhoff and Ms. Meridee Moore.

Exelixis Interviews and Considers Farallon Candidates and Announces Share Repurchase

In response to Farallon’s identification of five potential Board candidates, beginning on March 18, 2023, and continuing throughout the week of March 20, 2023, members of the Board, including Drs. Papadopoulos, Morrissey, Willsey and Freire, and Julie Smith, and Jack Wyszomierski, moved quickly to schedule and then meet with each of the five Farallon candidates on at least thirteen separate occasions. Members of the Board also scheduled three additional meetings during this same time period with Dr. Rienhoff; however, these meetings were all cancelled by Dr. Rienhoff. On March 19, 2023, Dr. Papadopoulos met and interviewed Ms. Moore. During the course of this discussion Dr. Papadopoulos and Ms. Moore mutually agreed that she would not continue to pursue a potential Board nomination. Ms. Moore did not meet with any other members of the Board. Throughout the course of the extensive interview process with Farallon’s five potential candidates, the discussions focused on the candidate’s qualifications, including any meaningful scientific, medical and biopharmaceutical industry expertise, along with the candidate’s expected ability and desire to contribute to the Board as independent Board members and ultimate achievement of Exelixis’ goals. Following the completion of these interviews, it was the consensus of the participating Board members that Messrs. Heyman and Oliver, Jr. would be excellent candidates for

the Board, based on their extensive experience in the biopharmaceutical industry and apparent alignment with the company’s mission and goals.

On March 20, 2023, Exelixis publicly announced the company’s $550 million share repurchase program, which the Board had approved at its meeting on March 16, 2023.

On March 20, 2023, a meeting also took place between Exelixis’ representatives, including Drs. Papadopoulos, Morrissey and Willsey, and Farallon’s representatives, including Mr. Dreyfuss and Drs. Devine and Roberts. During this meeting, the participants discussed Farallon’s views with regard to the composition of the Board, including the five individuals identified by Farallon as potential Board candidates. During the meeting, Dr. Papadopoulos raised the possibility of Farallon’s Dr. Roberts himself serving as a Board member and again invited Farallon to enter into an appropriately protective and customary confidentiality agreement to allow Farallon to have access to certain non-public information regarding Exelixis, consistent with the offers Dr. Papadopoulos had proposed at both the March 8 Meeting and the March 17 Meeting. During this meeting, Farallon’s representatives stated that Farallon would consider entering into such a confidentiality agreement and reiterated their belief that the Board should add new directors as part of a membership refresh. Also during this meeting, Exelixis representatives described the company’s annual review procedures and process with respect to Board composition and the Farallon representatives raised the possibility that additional Exelixis directors (in addition to the four directors Farallon proposed to depart from the Board in 2023) agree to leave the Board in 2024 (the Proposed 2024 Additional Director Departures).

On March 20, 2023, Farallon filed its initial Schedule 13D with respect to its ownership of shares of Exelixis’ common stock (Common Stock), reporting beneficial ownership of 7.2% of Exelixis’ outstanding shares of Common Stock. The Farallon Schedule 13D indicated that Farallon may be deemed to have formed a “group” with Mr. Johnson and Caligan, within the meaning of Section 13(d)(3) of the Exchange Act and Rule 13d-5(b)(1) thereunder. Caligan, on the same day, filed its initial Schedule 13D with respect to its ownership of Exelixis Common Stock, reporting beneficial ownership of 0.26% of Exelixis’ outstanding shares of Common Stock. The Caligan Schedule 13D indicated that Caligan may be deemed to have formed a “group” with Farallon, within the meaning of Section 13(d)(3) of the Exchange Act and Rule 13d-5(b)(1) thereunder.

On March 21, 2023, Dr. Rienhoff emailed Dr. Papadopoulos to inform Exelixis that he was no longer interested in pursuing a nomination to the Board and would not be participating in further meetings with Board members.

On March 21, 2023, the Board also held an update call, with members of Exelixis’ senior management and representatives from Paul Weiss in attendance. During the course of this call, the Board members discussed the ongoing conversations with Farallon and related matters.

On March 23, 2023, Exelixis received Farallon’s notice of its intent to nominate Messrs. Heyman, Johnson and Oliver, Jr. for election to the Board at the 2023 Annual Meeting (the Nomination Notice).

Later on March 23, 2023, the Board held an update call with members of the company’s senior management and representatives from Paul Weiss in attendance. During this call, the Board members discussed the ongoing discussions with Farallon, the Nomination Notice and related matters.

On March 24, 2023, representatives of Exelixis and Farallon held a meeting to discuss Exelixis’ business strategies, capital allocation framework, including its R&D processes, and the terms of a potential cooperation agreement between the parties. During this meeting, the participants also discussed the possibility of Dr. Roberts serving as a Board member and again discussed the possibility for Exelixis to provide non-public information to Farallon subject to the terms of an appropriately protective and customary confidentiality agreement, consistent with prior discussions between the parties at previous meetings with Farallon.

Over the course of March 24 and 25, 2023, Dr. Papadopoulos and Dr. Roberts had several conversations regarding the potential terms of a cooperation agreement and again discussed the possibility of Exelixis providing non-public information to Farallon subject to an appropriately protective and customary confidentiality agreement. The conversations culminated during the evening of March 25, 2023, when Dr. Roberts placed a phone call to Dr. Papadopoulos, during which Dr. Roberts suggested that Farallon and Exelixis could begin to work on “crafting a good faith public statement” announcing a settlement between the parties and that representatives of Farallon and Exelixis could look forward to “having the other parties over for a dinner to heal wounds.” Dr. Papadopoulos reiterated his offer, as a show of goodwill, to sign a two-year, rather than the one-year originally proposed, lock up for his personal shares, largely acquired through open market purchases over the years. Dr. Roberts also said that his counsel would be providing Exelixis with a written term sheet detailing the Farallon proposal.

In the overnight hours between March 25 and March 26, 2023, Dr. Papadopoulos received an email from Dr. Roberts attaching the term sheet setting forth Farallon’s proposal regarding certain key terms of the previously discussed cooperation agreement and related confidentiality agreement, pursuant to which Exelixis could provide non-public information to Farallon (the March 25/26 Term Sheet). The March 25/26 Term Sheet proposed, among other things, that:

In addition, the March 25/26 Term Sheet would have required that, prior to January 1, 2024, Exelixis confirm to Farallon in writing that all material non-public information (if any) provided to Farallon by Exelixis or its representatives under the terms of the proposed confidentiality agreement had been publicly disclosed or did not continue to constitute material non-public information (this is known as a “cleansing provision”).

On March 26, 2023, Dr. Papadopoulos sent an email to Dr. Roberts, representatives of Paul Weiss, counsel to Exelixis, and representatives of Schulte Roth & Zabel LLP (SRZ), outside counsel to Farallon, suggesting that Paul Weiss and SRZ begin preparation and negotiation of definitive documentation setting forth the agreement of the parties (a Cooperation Agreement) and draft documentation pursuant to which Exelixis could provide certain non-public information to Farallon (a Confidentiality Agreement).

Later in the day of March 26, 2023, representatives of Paul Weiss and SRZ met to discuss the March 25/26 Term Sheet (the March 26 Meeting). During this March 26 Meeting, representatives of Paul Weiss, on behalf of Exelixis, communicated, among other things, that Exelixis would agree to Farallon’s proposal regarding an “R&D and strategy day” for investors prior to 2024, and, following Farallon’s receipt of non-public information about the company pursuant to the terms of an appropriately protective and customary confidentiality agreement, including with respect to the term of the confidentiality obligations thereunder, would plan to invite Farallon to present to the Board on Farallon’s perspectives and

recommendations with respect to the company’s business strategies and capital allocation priorities and practices based on its review of such non-public information. Representatives of Paul Weiss, on behalf of Exelixis, further confirmed that the company was willing to agree to the restriction on the sale of shares of Exelixis Common Stock by Dr. Papadopoulos for the next 24-months, except under specific limited circumstances, and that Exelixis would be willing to agree to the “cleansing provision” requested by Farallon requiring Exelixis to confirm that Farallon was not in possession of material non-public information as of January 1, 2024.

During the course of the March 26 Meeting, representatives of Paul Weiss, on behalf of Exelixis, informed representatives of SRZ that Exelixis would only provide non-public information about the company’s strategy, capital allocation framework and R&D processes to the extent the company was able to make a reasonable determination that such information was appropriate and would not put the company at risk. The Paul Weiss representatives also conveyed that Exelixis would expect Farallon to agree that it would only make reasonable requests with respect to accessing the company’s non-public information. Both of these requests were, as Paul Weiss explained, consistent with the intent of the information sharing offer originally proposed by Dr. Papadopoulos during the earlier meetings with Farallon. In addition, the Paul Weiss representatives, on behalf of Exelixis, stated that Exelixis would not agree to be required to provide Farallon with any material non-public information that the company believed in good faith would not otherwise become public prior to January 1, 2024 (the Cleansing Date). Following the March 26 Meeting, representatives of Paul Weiss provided representatives of SRZ a revised term sheet (the Revised March 26 Term Sheet) reflecting the terms communicated during the March 26 Meeting.

On March 27, 2023, Paul Weiss, on behalf of Exelixis, provided SRZ, on behalf of Farallon, initial drafts of the Cooperation Agreement and the Confidentiality Agreement. The Cooperation Agreement provided by Paul Weiss contemplated, among other things, that:

The initial draft of the Confidentiality Agreement provided by Paul Weiss, on behalf of Exelixis, to SRZ, on behalf of Farallon, contemplated that, for a period of five months, Exelixis would provide Farallon with certain information, data and studies, including with respect to Exelixis’ capital allocation policies and practices, and that Farallon would be required to keep such information confidential for a period of five years (the Standard Confidentiality Period). As discussed during the March 26 Meeting, Exelixis believed this period was appropriate given the highly sensitive and proprietary nature of the non-public information that could be provided under the proposed confidentiality agreement, and a common time period in the biopharmaceutical industry for maintaining the confidentiality of such information. In the draft, Exelixis also agreed to “cleanse” Farallon of any material non-public information provided to Farallon as a result of the Confidentiality Agreement by the Cleansing Date, with the exception that Exelixis would not be required to disclose any information to Farallon that Exelixis did not, in good faith, believe would be possible to make public prior to the Cleansing Date. As proposed by Exelixis, Exelixis’ obligations to provide information under the Confidentiality Agreement was subject to the company’s ability to reasonably determine the scope of information that would be shared with Farallon.

Also on March 27, 2023, Farallon filed an amendment to the Schedule 13D previously filed by Farallon, reporting that Farallon had submitted the Nomination Notice to Exelixis on March 23, 2023. Caligan also filed an amendment to the Schedule 13D previously filed by Caligan, reporting that Mr. Johnson had entered into an agreement with Farallon pursuant to which, among other things, Mr. Johnson had agreed with Farallon to be nominated by Farallon for election to the Board at the 2023 Annual Meeting.

On March 28, 2023, representatives from Paul Weiss received revised drafts of the Cooperation Agreement and the Confidentiality Agreement from representatives of SRZ. The revised draft of the Cooperation Agreement proposed, among other things, that the Board would form a four-person “Strategy and Capital Allocation Committee” to support the Board’s review of Exelixis’ strategy and capital allocation practices. The revised Farallon draft also required the Board to expressly agree to undertake the Proposed 2024 Additional Director Departures and appoint one new director nominated by Farallon to the Nominating and Corporate Governance Committee of the Board (the NomGov Committee) and both new directors nominated by Farallon to the R&D Committee. Finally, the revised Farallon draft included a requirement that Paul Weiss would send an email, on behalf of Exelixis, to SRZ, on behalf of Farallon, confirming Exelixis’ agreement to Farallon making a presentation to the full Board. The revised Farallon draft deleted the ability of Exelixis to make a reasonable determination regarding the scope of information that would be provided to Farallon, the effect of which would be to require Exelixis to provide any and all information requested by Farallon, including any non-public and highly proprietary information regarding its R&D policies and practices, strategy, and capital allocation policies and practices. The revised draft Confidentiality Agreement provided by SRZ, on behalf of Farallon, also shortened the period Farallon was required to preserve confidentiality under the Standard Confidentiality Period from five years to 12 months, the effect of which would be that after such twelve-month period Farallon would be free to share without restriction competitively sensitive information regarding Exelixis’ proprietary systems and processes, intellectual property, in-process pipeline and clinical developments, HR matters, and pre-clinical and clinical studies and results.

On March 29, 2023, Exelixis provided its form D&O questionnaire to each of Messrs. Heyman and Oliver, Jr., which each candidate subsequently completed and returned to the company on March 31, 2023, and April 1, 2023, respectively. Exelixis further informed each candidate that they would be receiving requests for their written consent to a background check via email. Messrs. Heyman and Oliver, Jr., provided such written consent on April 5, 2023, and April 4, 2023, respectively.

On March 30, 2023, representatives of Paul Weiss, on behalf of Exelixis, distributed further revised drafts of the Cooperation Agreement and the Confidentiality Agreement to SRZ, on behalf of Farallon. The revised draft Cooperation Agreement provided, among other things, that the Board would form a “Finance Committee” to assist the Board in its review of the company’s capital allocation practices (consistent with the company’s original draft) and appoint one new director nominated by Farallon to the NomGov Committee (consistent with Farallon’s proposal). The revised draft Cooperation Agreement also provided that, among other things, Exelixis would be able to make a reasonable determination regarding the scope of information that would be provided to Farallon and that Farallon would agree to only make reasonable requests regarding the company’s non-public information. Furthermore, Exelixis would not be obligated to provide Farallon with non-public information that Exelixis determined in good faith would not otherwise have been made public prior to the Cleansing Date. The revised draft of the Confidentiality Agreement reflected that any requests being made by Farallon would have to be directed to Dr. Morrissey in order to ensure an orderly and efficient process of information sharing, and reinstated the Standard Confidentiality Period in order to protect Exelixis from the potential disclosure of its highly sensitive and proprietary non-public information (the March 30 Confidentiality Agreement).

Farallon Demands Unprecedented Breadth and Depth of Access to Exelixis Confidential Information

Later in the day of March 30, 2023, representatives of Exelixis and Farallon held a telephone call (the March 30 Call) to discuss the scope of information that Exelixis would be required to provide under the terms of the Cooperation and Confidentiality Agreements under discussion between the parties. During this call, representatives of Exelixis noted that Farallon’s proposal would require the company to disclose an unprecedented breadth and depth of highly sensitive and proprietary non-public information regarding the company. Exelixis representatives further indicated that Farallon’s position was substantially different from the type of information that had initially been the subject of discussion between the company and Farallon. However, Exelixis indicated that, in a desire to clarify the type of information that would be reasonable and satisfactory to Farallon, the company would be willing to consider a specific and limited list of the categories of information that would be provided to Farallon.

During the March 30 Call, the Farallon representatives responded that Farallon’s position was that Farallon should have the same unfettered access to Exelixis’ highly sensitive and proprietary non-public information as the members of the Board, which effectively meant that Farallon could have access to every piece of information in the possession of the company but without the full scope of attendant duties and obligations (including fiduciary obligations to all the company’s shareholders) owed by members of the Board to the company.

Following the March 30 Call, representatives of Paul Weiss received further revised drafts of the Cooperation Agreement and the Confidentiality Agreement from representatives of SRZ. The revised draft Cooperation Agreement contemplated, among other things, that the Board would create a four-person “Capital Allocation Committee” to support the Board’s review of Exelixis’ capital allocation practices and that Mr. Heyman would join the R&D Committee. The revised draft Cooperation Agreement removed the ability of Exelixis to make a reasonable determination regarding the scope of information that would be shared with Farallon. Farallon’s revised draft further eliminated the requirement that Farallon could only make reasonable requests with respect to accessing Exelixis’ non-public information, meaning that Farallon reserved the right make unreasonable requests with respect to Exelixis’ highly sensitive and proprietary non-public information. The Farallon revisions to the draft of the Confidentiality Agreement provided on March 30, 2023, provided, among other things, that Exelixis would be obligated to provide Farallon with relevant materials provided to the Board and/or R&D Committee prior to the date of the Confidentiality Agreement and relevant material provided to the Board and/or the R&D Committee after the date of the Confidentiality Agreement but prior to October 1, 2023. In addition, the Farallon draft would require, if Farallon desired (and with only two business days’ notice), Dr. Morrissey to meet with Farallon on a weekly basis—every week of the year through October 1, 2023—to discuss Exelixis’ non-public information related to the company’s R&D policies and practices. At Farallon’s option, certain other Exelixis executives could have been substituted for Dr. Morrissey at these meetings. Finally, the revised Farallon draft shortened the Standard Confidentiality Period from five years to two years, meaning that after two years Farallon would be free to share without restriction competitively sensitive information regarding Exelixis’ proprietary systems and processes, intellectual property, in-process pipeline and clinical developments, HR matters, and pre-clinical and clinical studies and results.

From March 30 to April 2, 2023, certain members of Exelixis’ senior management and the Board met to discuss the unprecedented terms that Farallon continued to propose in the drafts received from Farallon’s counsel on March 30, and the risks and potential liabilities to the company and its shareholders if the company was not permitted to make reasonable determinations with respect to the scope of competitively sensitive and non-public information to be provided to Farallon, particularly when Farallon would then be permitted to publicly share such competitively sensitive non-public information after a two-year period. Such members of senior management and the Board also noted that Farallon continued to request access to the same level of information as that provided to the Board but without agreeing to the heightened confidentiality obligations owed by Board members to the company (including fiduciary obligations to all of the company’s shareholders) that are indefinite in duration. Members of the Board noted that the Board had determined, at the time of their interviews, that Messrs. Heyman and Oliver, Jr. were excellent candidates, but that the Board could not concede to Farallon’s information and access demands due to the open-ended and far-reaching scope of disclosure requested and the related risks and potential liabilities of such disclosures to Exelixis and its shareholders.

On April 3, 2023, representatives of SRZ, on behalf of Farallon, and Paul Weiss, on behalf of the company, met to discuss the drafts of the definitive documentation that had been shared by the parties. Representatives of Paul Weiss, on behalf of Exelixis, explained to SRZ, on behalf of Farallon, that Exelixis was not willing to enter into the draft Confidentiality Agreement on the terms proposed by Farallon due to the open-ended and far-reaching scope of disclosure required by Farallon, Farallon’s continuous rejection of Exelixis’ duty to make a reasonable determination regarding the scope of competitively sensitive, non-public information to be shared with Farallon, Farallon’s refusal to only make reasonable requests with respect to accessing the company’s non-public information and Farallon’s insistence upon limiting the confidentiality period for Exelixis’ competitively sensitive, non-public information under the Confidentiality Agreement to just two years.

Later in the day on April 3, 2023, representatives of Paul Weiss distributed a revised draft of the Cooperation Agreement to representatives of SRZ that Exelixis believed reflected terms that had, in almost all cases, previously been accepted or proposed by Farallon. Exelixis did not provide a revised draft of the Confidentiality Agreement, consistent with the discussion between the parties’ representatives earlier on April 3, 2023.

On April 4, 2023, Dr. Papadopoulos, while traveling internationally, received a voicemail from Dr. Roberts and a subsequent email from Dr. Roberts, indicating Dr. Roberts’s surprise that Exelixis was not willing to enter into the Confidentiality Agreement and stating his belief that the company was “backing out of [their] agreement.” In his email Dr. Roberts noted that Farallon had been willing to sign the last draft of the Confidentiality Agreement prepared by Exelixis (the March 30 Confidentiality Agreement), notwithstanding the fact that Farallon had subsequently sent to Exelixis its own draft of the Confidentiality Agreement and had not accepted many terms contained in the March 30 Confidentiality Agreement prepared by Exelixis.

On April 5, 2023, without prior notice to Exelixis, Farallon issued a press release that, among other things, demanded Exelixis return “excess capital” to shareholders and indicated that Farallon would nominate Messrs. Heyman, Johnson and Oliver, Jr. as candidates for election to the Board at the 2023 Annual Meeting.

On April 5, 2023, Exelixis issued a press release reiterating its commitment to shareholder value creation and describing its continued recent engagement with Farallon. Exelixis’ press release stated that the company and Farallon reached a near-final agreement to avoid a proxy contest that would have resulted in the appointment two of Farallon’s nominees, Messrs. Heyman and Oliver, Jr., the retirement announcement of two long-standing existing directors and the formation of a new Capital Allocation Committee, all of which had initially been proposed by Farallon. The company’s press release further disclosed that the company was willing to consider sharing non-public information with Farallon pertaining to the company’s R&D strategy; however, because Farallon had demanded a highly unusual breadth and depth of information access as a non-negotiable part of any settlement, including unprecedented access to competitively sensitive non-public information regarding the company’s pipeline, people and clinical trial data, the company could not enter into a confidentiality agreement on such terms.

On April 6, 2023, the Farallon-Caligan Group filed a preliminary proxy statement to be used in connection with the 2023 Annual Meeting. In this filing, among other things, the Farallon-Caligan Group stated that “Farallon was willing to sign the March 30 Confidentiality Agreement,” referring to the draft provided by Paul Weiss to SRZ on March 30, 2023.

Later in the day on April 7, 2023, representatives of Paul Weiss, on behalf of Exelixis, contacted SRZ, on behalf of Farallon, indicating that, to the extent there had been a miscommunication between the parties, Exelixis desired to clarify that misunderstanding. Representatives of Paul Weiss, on behalf of Exelixis, informed representatives of SRZ, on behalf of Farallon, that if Farallon were prepared to execute the Cooperation Agreement and the Confidentiality Agreement specifying that Exelixis was only required to provide non-public information about the company’s strategy, capital allocation framework and R&D processes that was reasonably requested by Farallon and reasonably agreed to by Exelixis and reinstating the five-year Standard Confidentiality Period, then so was the company. Representatives of SRZ, on behalf of Farallon, stated Farallon’s agreement to move forward with the March 30 drafts referred only to the Confidentiality Agreement and they would check whether Farallon would be willing to agree on the Cooperation Agreement as well. Later that day, representatives of SRZ, on behalf of Farallon, contacted representatives of Paul Weiss, on behalf of Exelixis, and stated that Farallon was unwilling to execute either of the Confidentiality Agreement or the Cooperation Agreement. Contrary to the statement in the revised preliminary proxy statement filed by the Farallon-Caligan Group on April 21, 2023 (the Revised Farallon-Caligan Preliminary Proxy Statement), at no time during this second call did the representatives of SRZ indicate that Farallon “remained willing to reach a reasonable resolution.” In fact, when asked during the call whether Farallon was amenable to reinitiating settlement discussions, the representatives of SRZ stated that Farallon was no longer willing to settle and that Exelixis should expect to see Farallon at the company’s 2023 Annual Meeting. Indeed, if the representatives of SRZ had communicated that Farallon remained willing to reach a reasonable resolution, the representatives of Paul Weiss would have asked the representatives of SRZ what Farallon had in mind for a reasonable resolution, especially in light of how close the parties had come previously to reaching a settlement agreement.

On April 10, 2023, the Board held an update call, with members of the company’s senior management and representatives of Paul Weiss, Centerview Partners and Morgan Stanley in attendance. At this meeting, members of the Board discussed the ongoing discussions with Farallon, the preliminary proxy filed by the Farallon-Caligan Group and potential next steps.

On April 12, 2023, the NomGov Committee held a meeting, with members of the company’s senior management and representatives of Paul Weiss in attendance. At this meeting, members of the NomGov Committee discussed the ongoing negotiations with Farallon, the interviews conducted with the five potential candidates initially proposed by Farallon, the positive reception of the Board members to the candidacy of Messrs. Heyman and Oliver, Jr. and the fact that Mr. Feldbaum and Dr. Marchesi had recently informed the Board of their decision not to stand for re-election to the Board at the 2023 Annual Meeting. The NomGov Committee further discussed the qualifications of, and subsequently determined to support the election of, Messrs. Heyman and Oliver, Jr., after they were nominated by Farallon to stand for election at the 2023 Annual Meeting as directors of the company and determined to recommend that the Board recommend in favor of the candidacy of Messrs. Heyman and Oliver, Jr.

Later in the day on April 12, 2023, the Board held a meeting, with members of Exelixis’ senior management and representatives of Paul Weiss. At this meeting, members of the NomGov Committee discussed the recommendation of the NomGov Committee to the Board. The Board discussed this recommendation, the qualifications of Messrs. Heyman and Oliver, Jr. to stand for election at the 2023 Annual Meeting as directors of Exelixis, and determined to recommend in favor of the candidacy of Messrs. Heyman and Oliver, Jr.

On April 13, 2023, Exelixis issued a press release announcing that Mr. Feldbaum and Dr. Marchesi would not stand for re-election to the Board at the 2023 Annual Meeting and disclosing the Board’s recommendation in favor of the candidacy of Messrs. Heyman and Oliver, Jr.

On April 17, 2023, Exelixis filed its preliminary proxy statement to be used in connection with the 2023 Annual Meeting.

On April 18, 2023, Farallon delivered to the company a demand for a copy of Exelixis’ stockholder list pursuant to Section 220 of the Delaware General Corporation Law, along with a proposed confidentiality agreement in respect of the demand.

On April 21, 2023, the Farallon-Caligan Group filed the Revised Farallon-Caligan Preliminary Proxy Statement.

On April 24, 2023, Paul Weiss, on behalf of Exelixis, delivered a letter to SRZ correcting the record on Farallon’s mischaracterization of the Second April 8 Phone Call and asking SRZ to clarify the inaccurate assertion made in the Revised Farallon-Caligan Preliminary Proxy Statement that Farallon remained willing to reach a reasonable resolution.

On April 24, 2023, Paul Weiss sent a reply to Farallon’s April 18, 2023 letter regarding Farallon’s demand pursuant to Section 220 of the Delaware General Corporation Law and included a revised confidentiality agreement in respect of the demand that the company was prepared to execute.

On April 25, 2023, representatives of Paul Weiss and SRZ held a telephone call during which the representatives of SRZ expressed their disagreement with the assertions contained in the Paul, Weiss letter of April 24, 2023. During the same call, the representatives of SRZ asked the Paul Weiss representative whether Exelixis would be willing to enter into a settlement with Farallon. The representative of Paul Weiss indicated that Exelixis had always been and remained open to a reasonable resolution and asked the SRZ representatives to articulate a proposal. The representatives of SRZ stated that Farallon would be amenable to a settlement that included adding Mr. Johnson on the Board’s slate of director nominees for the 2023 Annual Meeting. In response, the Paul Weiss representative indicated that Paul Weiss would take such offer back to Exelixis, but that it was unlikely to be acceptable to the company. The representatives of SRZ then asked the Paul Weiss representative to consult with Exelixis and to revert with another proposal.

On April 25, 2023, SRZ, on behalf of Farallon, sent Paul Weiss a further revised confidentiality agreement in respect of Farallon’s demand pursuant to Section 220 of the Delaware General Corporation Law.

On April 26, 2023, representatives of Paul, Weiss and SRZ held a telephone call during which the Paul, Weiss representatives communicated that Exelixis would be willing to add a new director to the Board who would be “best in class” with respect to both reputation and expertise in R&D and that Farallon would have the right to consent to such director, which consent would not be unreasonably withheld. The remaining terms of the settlement agreement would be consistent with Exelixis’ March 30 draft cooperation agreement, except that the information sharing and related confidentiality provisions would be removed.

Also on April 26, 2023, Paul Weiss, on behalf of Exelixis, sent SRZ a further revised confidentiality agreement in respect of Farallon’s demand pursuant to Section 220 of the Delaware General Corporation Law that the company was prepared to execute.

On April 27, 2023, SRZ, on behalf of Farallon, sent Paul Weiss a further revised confidentiality agreement in respect of Farallon’s demand pursuant to Section 220 of the Delaware General Corporation Law.

On April 28, 2023, Paul Weiss, on behalf of Exelixis, sent SRZ a further revised confidentiality agreement in respect of Farallon’s demand pursuant to Section 220 of the Delaware General Corporation Law that the company was prepared to execute.

On April 30, 2023, SRZ, on behalf of Farallon, sent Paul Weiss a further revised confidentiality agreement in respect of Farallon’s demand pursuant to Section 220 of the Delaware General Corporation Law. Later that day, Exelixis and Farallon agreed to the terms of such confidentiality agreement.

On May 1, 2023, Exelixis filed its definitive proxy statement to be used in connection with the 2023 Annual Meeting.

Set forth below is a summary of the bid/ask between the parties on key issues discussed by Farallon and its advisors and Exelixis and its advisors as of April 3, 2023.

In addition, the Board recommends election of two Farallon-Caligan nominees:

As described previously, Farallon has notified Exelixis of its intent to nominate three candidates for election as directors at the Annual Meeting. As a result, the election of directors will be considered a contested election as defined in Exelixis’ Bylaws and directors will be elected on a plurality basis. This means that the eleven (11) director nominees receiving the greatest number of “FOR” votes will be elected. “WITHHOLD” votes and any broker non-votes will be counted for purposes of determining if there is a quorum for this vote but will not be counted as votes cast and will result in the applicable nominee(s) receiving fewer votes cast “FOR” such nominee(s).

In the event that Farallon withdraws its nominees, abandons its solicitation or fails to comply with the universal proxy rules after a shareholder has already granted proxy authority, shareholders can still sign and date a later submitted GOLD proxy card. In the event that Farallon withdraws its nominees, abandons its solicitation or fails to comply with the universal proxy rules, any votes cast in favor of the Farallon-Caligan nominees will be disregarded and not be counted, whether such vote is provided on Exelixis’ GOLD proxy card or the Farallon-Caligan Group’s proxy card.

Our Board recommends that you vote “WITHHOLD” on the non-recommended Farallon-Caligan nominee and encourages all stockholders to vote “FOR” the Board’s recommended nominees, each of whom is highly qualified. You may receive solicitation materials from the Farallon-Caligan Group, including proxy statements and proxy cards. Exelixis is not responsible for the accuracy or completeness of any information provided by or relating to the Farallon-Caligan Group or the Farallon-Caligan nominees contained in solicitation materials filed or disseminated by or on behalf of the Farallon-Caligan Group or any other statements the Farallon-Caligan Group may make.

If you are a registered holder and submit a validly executed GOLD proxy card but do not specify how you want to vote your shares with respect to the election of directors, then your shares will be voted in line with the Board’s recommendation with respect to the proposal, i.e., “FOR” the eleven nominees recommended by the Board and named in this proxy statement and “WITHHOLD” on the non-recommended Farallon-Caligan nominee. Each nominee has consented to serve if elected. If any of the nominees nominated or recommended by the Board become unavailable to serve as a Director before the Annual Meeting, the Board may designate a substitute nominee. In that case, the persons named as proxies will vote for the substitute nominee designated by the Board. At this time, the Board knows of no reason why any of the nominees nominated or recommended by the Board would not be able to serve as a director if elected.

We refer stockholders to the Farallon-Caligan Group’s proxy statement (the Farallon-Caligan Proxy Statement) for the name, background, qualifications and other information concerning the non-recommended Farallon-Caligan nominee. The Farallon-Caligan Proxy Statement and form of proxy distributed by the Farallon-Caligan Group is available free of charge on the SEC’s website at www.sec.gov.

Exelixis Recommended Farallon-Caligan Nominees

THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” EACH OF THE FOLLOWING PERSONS NOMINATED OR RECOMMENDED BY THE BOARD:

We may only accomplish our mission to help cancer patients if the medicines we discover and develop are innovative and fulfill unmet medical needs. Furthermore those medicines must be safe and of the highest quality, available expeditiously when prescribed by healthcare professionals and accessible to cancer patients without regard to their insurance status or ability to pay.

Key Components:

We connect with communities in which our employees live and work, and like-minded organizations that are dedicated to improving cancer care, education, outreach and advocacy. Through our giving initiatives, we extend our impact and create partnerships to benefit patients and the healthcare professionals and researchers championing their care. We also fund educational requests, sponsorships and charitable organizations, and support employee giving and volunteerism, knowing that together we can do more for all the communities we serve.

Key Components:

We nurture a culture in which all employees feel empowered to be their authentic selves. We respect and appreciate each employee’s unique perspective and experiences, and believe that celebrating, encouraging and supporting both similarities and differences contributes to our company mission. We take pride in our core corporate values to Be Exceptional, Excel for Patients and Exceed Together, and remain committed to fostering a culture in which each and every employee feels a sense of belonging to the Exelixis team and our mission.

Key Components:

We are committed to conducting business in a way that respects our environment and the Earth’s changing climate. We have already incorporated many environmentally sustainable practices into our facilities and operations, and we plan to incorporate more of these practices as we continue to grow. As part of this commitment, we recognize that climate change threatens human safety and well-being on a dramatic scale. We feel all businesses—especially those like ours that are dedicated to human health—have a duty to minimize their impact on climate change and promote a long and prosperous future for all of Earth’s inhabitants.

Environmental Management

Key Components:

Each communication must set forth the name and address of the stockholder as it appears in Exelixis’ records (and, if the stock is held by a nominee, the name and address of the beneficial owner of the stock). After confirming the stock ownership of the author of the communication, the Corporate Secretary will review and evaluate the communication, and shall have the authority to and will screen out communications from stockholders that are not directly related to the duties and responsibilities of the Board. The Corporate Secretary may also disregard duplicative communications. If deemed directly related to the duties and responsibilities of the Board, the Corporate Secretary will forward the communication, depending on the subject matter, to the Chair of the Nominating and Corporate Governance Committee, the Chair of the Audit Committee, the Chair of the Board, the independent directors, or the full Board, as deemed appropriate.

Stockholder Outreach

We maintain a robust investor relations and corporate governance program for stockholder outreach to provide regular updates on our business, including but not limited to financial results, clinical trial readouts, pipeline advancement, business development efforts and upcoming milestones, as well as corporate governance related matters, including our executive

compensation program, human capital management practices, diversity, equity and inclusion programs and initiatives, governance practices, ESG disclosures (including the CV&S report) and other areas of our business, to elicit a better understanding of their concerns and perspectives. We bi-annually request engagement meetings with our top institutional shareholders, representing over 65% of our total outstanding shares. Additionally, we accept 100% of engagement meetings requested by our top shareholders. As a result, we have implemented the feedback received from our stockholders into our executive compensation program, human capital management practices, diversity, equity and inclusion programs and initiatives, governance practices, ESG disclosures (including the CV&S report) and other areas of our business. For additional details about our stockholder outreach efforts during fiscal 2022, please see “Compensation Discussion and Analysis—How We Determine Executive Compensation—Stockholder Outreach.”

THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” PROPOSAL 2.