In connection with the merger by and between Ikena Oncology, Inc. and Inmagene Biopharmaceuticals (the "Merger"), pursuant to the Agreement and Plan of Merger, dated as of December 21, 2024, the Issuer entered into a subscription agreement with certain accredited investors ("PIPE Investors"), pursuant to which, following the closing of the Merger, the PIPE Investors subscribed for and purchased an aggregate of 2,508,337 Shares, after giving effect to the Reverse Stock Split, at a price of approximately $29.90 per Share (the "PIPE"). In connection with the PIPE, OrbiMed Private Investments VI, LP ("OPI VI"), a limited partnership organized under the laws of Delaware, purchased 83,611 Shares at a price of approximately $2.49. The source of funds for such purchases was the working capital of OPI VI.

In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, OrbiMed GP is the general partner of OPI VI, pursuant to the terms of the limited partnership agreement of OPI VI. Pursuant to this agreement and relationship, OrbiMed GP has discretionary investment management authority with respect to the assets of OPI VI. Such authority includes the power to vote and otherwise dispose of securities held by OPI VI. The number of outstanding Shares of the Issuer attributable to OPI VI is 753,063 Shares, which amount includes 465,178 Non-Voting Shares that are convertible to Shares. OrbiMed GP, pursuant to its authority under the limited partnership agreement of OPI VI, may be considered to hold indirectly 753,063 Shares, which amount includes 465,178 Non-Voting Shares that are convertible to Shares. In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, OrbiMed Genesis is the general partner of Genesis, pursuant to the terms of the limited partnership agreement of Genesis. Pursuant to this agreement and relationship, OrbiMed Genesis has discretionary investment management authority with respect to the assets of Genesis. Such authority includes the power to vote and otherwise dispose of securities held by Genesis. The number of outstanding Shares of the Issuer attributable to Genesis is 20,691 Shares, which amount includes 13,107 Non-Voting Shares that are convertible to Shares. OrbiMed Genesis, pursuant to its authority under the limited partnership agreement of Genesis, may be considered to hold indirectly 20,691 Shares, which amount includes 13,107 Non-Voting Shares that are convertible to Shares. In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, OrbiMed Advisors is the managing member of OrbiMed GP and OrbiMed Genesis, pursuant to the terms of the limited liability company agreements of OrbiMed GP and OrbiMed Genesis. Pursuant to these agreements and relationships, OrbiMed Advisors and OrbiMed GP have discretionary investment management authority with respect to the assets of OPI VI. OrbiMed Advisors and OrbiMed Genesis have discretionary investment management authority with respect to the assets of Genesis. Such authority includes the power of OrbiMed GP to vote and otherwise dispose of securities held by OPI VI and the power of OrbiMed Genesis to vote and otherwise dispose of the securities held by Genesis. The number of outstanding Shares attributable to OPI VI is 753,063 Shares, which amount includes 465,178 Non-Voting Shares that are convertible to Shares, and the number of Shares attributed to Genesis is 20,691 Shares, which amount includes 13,107 Non-Voting Shares that are convertible to Shares. OrbiMed Advisors, pursuant to its authority under the terms of the limited liability company agreements of OrbiMed GP and OrbiMed Genesis, may also be considered to hold indirectly 773,754 Shares, which amount includes 478,285 Non-Voting Shares that are convertible to Shares. OrbiMed Capital is the investment advisor to WWH. OrbiMed Capital may be deemed to have voting and investment power over the securities held by WWH. Such authority includes the power of OrbiMed Capital to vote and otherwise dispose of securities held by WWH. The number of outstanding Shares attributable to WWH is 135,516 Shares, which amount includes 52,429 Non-Voting Shares that are convertible to Shares. OrbiMed Capital, as the investment advisor to WWH, may also be considered to hold indirectly 135,516 Shares, which amount includes 52,429 Non-Voting Shares that are convertible to Shares. David P. Bonita ("Bonita"), a member of OrbiMed Advisors, is a member of the Board of Directors of the Issuer and, accordingly, OrbiMed Advisors and OrbiMed GP may have the ability to affect and influence control of the Issuer. From time to time, Bonita may receive stock options or other awards of equity-based compensation pursuant to the Issuer's compensation arrangements for non-employee directors. Pursuant to an agreement with OrbiMed Advisors and OrbiMed GP, Bonita is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors and OrbiMed GP, which will in turn ensure that such securities or economic benefits are provided to OPI VI. Investors' Rights Agreement In addition, OPI VI, WWH, Genesis, and certain other stockholders of the Issuer entered into a Fourth Amended and Restated Investors' Rights Agreement with the Issuer (the "Investors' Rights Agreement"), dated as of December 18, 2020. Pursuant to the Investors' Rights Agreement and subject to the terms and conditions therein, the parties agreed that: Demand Registration Rights At any time beginning six months following the date of the effective date of the registration statement of the Issuer's initial public offering, the holders of at least 40% of the registrable securities then outstanding of the Issuer may make a written request that the Issuer register at least 20% their registrable securities (or a lesser percent if the anticipated aggregate offering price, net of expenses, would exceed $10 million). The Issuer is required to use commercially reasonable efforts to effect the registration and will pay all registration expenses, other than underwriting discounts and commissions, related to any demand registration. The Issuer is not obligated to effect more than two of these registrations. Piggyback Registration Rights Whenever the Issuer proposes to file a registration statement under the Securities Act, including a registration statement on Form S-3 as discussed below, other than with respect to certain excluded registrations, OPI VI, WWH, and Genesis will be entitled to notice of the registration and have the right, subject to limitations that the underwriters may impose on the number of Shares included in the registration, to include the Shares held by them in the registration. Form S-3 Registration Rights At any time after the Issuer is qualified to file a registration statement on Form S-3 under the Securities Act, and subject to limitations and conditions specified in the Investors' Rights Agreement, holders of at least 20% of the registrable securities then outstanding may make a written request that the Issuer prepare and file a registration statement on Form S-3 covering their Shares, so long as the aggregate price to the public equal or exceeds $3 million. The Issuer is not obligated to effect more than two of these Form S-3 registrations in any 12-month period. Registration Rights Agreement In connection with the consummation of the Merger and the PIPE, the Issuer entered into a registration rights agreement (the "Registration Rights Agreement") with the PIPE Investors, including OPI VI, pursuant to which the Issuer agreed that, within 45 calendar days after the closing of the Merger, the Issuer will file with the SEC (at the Issuer's sole cost and expense) a registration statement registering the resale of the Shares purchased in the PIPE. The foregoing descriptions of the Investors' Rights Agreement and the Registration Rights Agreement do not purport to be complete and are qualified in their entirety by reference to the full text of the Investors' Rights Agreement and the Registration Rights Agreement, which are filed as Exhibit 2 and Exhibit 3 and are incorporated herein by reference.

Exhibit 1. Joint Filing Agreement among OrbiMed Advisors LLC, OrbiMed Capital LLC, OrbiMed Genesis GP LLC, and OrbiMed Capital GP VI LLC. Exhibit 2. Fourth Amended and Restated Investors' Rights Agreement (incorporated by reference to Exhibit 4.2 to the Issuer's Registration Statement on Form S-1 (File No. 333-253919) filed with the SEC on March 5, 2021). Exhibit 3. Registration Rights Agreement (incorporated by reference to Exhibit 10.8 to the Issuer's Current Report on Form 8-K (File No. 001-40287) filed with the SEC on July 25, 2025.