On August 4, 2023, the Issuer consummated its merger with Pionyr Immunotherapeutics, Inc., a Delaware corporation ("Pionyr"), in accordance with the terms of the Agreement and Plan of Merger, dated August 4, 2023 (the "Merger Agreement"), by and among the Issuer, Portsmouth Merger Sub I, Inc., a Delaware corporation and a wholly owned subsidiary of the Issuer ("First Merger Sub"), Portsmouth Merger Sub II, LLC, a Delaware limited liability company and wholly owned subsidiary of the Issuer ("Second Merger Sub"), Pionyr, and Fortis Advisors LLC, as securityholder agent. Pursuant to the Merger Agreement, First Merger Sub merged with and into Pionyr, pursuant to which Pionyr was the surviving corporation and became a wholly owned subsidiary of the Issuer (the "First Merger"). Immediately following the First Merger, Pionyr merged with and into Second Merger Sub, pursuant to which Second Merger Sub was the surviving entity (together with the First Merger, the "Merger"). Prior to the Merger, OrbiMed Private Investments VI, LP ("OPI VI"), a limited partnership organized under the laws of Delaware, was a stockholder of Pionyr and OPI VI, OrbiMed Genesis Master Fund, L.P. ("Genesis"), a limited partnership organized under the laws of the Cayman Islands, and Worldwide Healthcare Trust PLC ("WWH"), a publicly-listed investment trust organized under the laws of England, were stockholders of the Issuer. Pursuant to the terms of the Merger Agreement, in return for the Class A shares of Pionyr held by OPI VI, OPI VI received 153,121 Non-Voting Shares, 353,192 shares of Series A Preferred Stock ("Series A Preferred Stock"), and 9,579,040 contingent value rights ("CVRs"). Following approval by the Issuer's stockholders of the conversion of the Series A Preferred Stock into Shares, each share of Series A Preferred Stock was automatically convertible into one Share; provided that if a holder of the Series A Preferred Stock was a holder of Non-Voting Shares prior to such conversion, such holder will receive Non Voting Shares to the extent such conversion would result in such holder beneficially owning more than 9.99% of the outstanding Shares. Each Non-Voting Share is convertible into one Share at any time at the option of the holder without payment or additional consideration, subject to a 9.99% beneficial ownership limitation that may be increased or decreased by the holder upon 61 days' notice to the Issuer. At a special meeting of the Issuer's stockholders on October 11, 2023, each share of Series A Preferred Stock was converted into one Share. On June 14, 2025, OPI VI, Genesis and WWH sent written notice to the Issuer of their increase of the beneficial ownership limitation to 19.99%. Due to the increase in the blocker, 6,042,193 Non-Voting Shares owned by the Reporting Person will convert to Shares on the 61st day after the date of the notice. Subject to the terms of the CVR Agreement (as defined below), as more particularly described in Item 6 below, each CVR entitles the holder thereof to receive certain cash and/or stock payments from 50% of the net proceeds, if any, related to the disposition of Pionyr's legacy assets within two years following the Closing Date (as defined in the Merger Agreement). The source of funds for such purchases was the working capital of OPI VI, Genesis and WWH.

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 7,768,790 Shares, which amount includes 5,317,501 Non-Voting Shares that are convertible to Shares. In addition, OPI VI holds 264,643 Non-Voting Shares. OrbiMed GP, pursuant to its authority under the limited partnership agreement of OPI VI, may be considered to hold indirectly 7,768,790 Shares, which amount includes 5,317,501 Non-Voting Shares that are convertible to Shares, and 264,643 Non-Voting 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 240,123, which amount includes 149,109 Non-Voting Shares that are convertible to Shares. In addition, Genesis holds 8,179 Non-Voting Shares. OrbiMed Genesis, pursuant to its authority under the limited partnership agreement of Genesis, may be considered to hold indirectly 240,123 Shares, which amount includes 149,109 Non-Voting Shares that are convertible to Shares, and 8,179 Non-Voting 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 7,768,790 Shares, which amount includes 5,317,501 Non-Voting Shares that are convertible to Shares, and the number of Shares attributed to Genesis is 240,123 Shares, which amount includes 149,109 Non-Voting Shares that are convertible to Shares. In addition, OPI VI holds 264,643 Non-Voting Shares and Genesis holds 8,179 Non-Voting 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 8,008,913 Shares, which amount includes 5,466,610 Non-Voting Shares that are convertible to Shares, and 272,822 Non-Voting 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 1,572,638 Shares, which amount includes 575,583 Non-Voting Shares that are convertible to Shares. In addition, WWH holds 53,572 Non-Voting Shares. OrbiMed Capital, as the investment advisor to WWH, may also be considered to hold indirectly 1,572,638 Shares, which amount includes 575,583 Non-Voting Shares that are convertible to Shares, and 53,572 Non-Voting 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. Support Agreement In connection with the execution of the Merger Agreement, the Issuer and Pionyr entered into stockholder support agreements (the "Support Agreements") with certain stockholders of the Issuer, including OPI VI, Genesis, and WWH. The Support Agreements provide that, among other things, each of the stockholders has agreed to vote, or cause to be voted, at the Issuer's stockholders' meeting to be held in connection therewith all of the Shares owned by such stockholder in favor of (i) the approval of the conversion of the Series A Preferred Stock into Shares in accordance with Nasdaq Listing Rule 5635(a), and, if deemed necessary by the Issuer, (ii) the approval of an amendment to the certificate of incorporation of the Issuer to authorize sufficient Shares for the conversion of the Series A Preferred Stock issued pursuant to the Merger Agreement. Contingent Value Rights Agreement In connection with the Merger, the Issuer and the Rights Agent (as defined in the CVR Agreement (as defined below)) entered into a contingent value rights agreement (the "CVR Agreement"), pursuant to which stockholders of Pionyr as of immediately prior to the First Effective Time (as defined in the Merger Agreement), including OPI VI, shall be entitled to one contractual CVR issued by the Issuer, subject to and in accordance with the terms and conditions of the CVR Agreement, for each share of Pionyr's common stock held by such stockholder immediately prior to the First Effective Time. Each CVR shall entitle the holder thereof to receive certain cash and/or stock payments from 50% of the net proceeds, if any, related to the disposition of Pionyr's legacy assets within two years following the Closing Date (as defined in the Merger Agreement). The CVRs are not transferable, except in certain limited circumstances as provided in the CVR Agreement, will not be certificated or evidenced by any instrument, and will not be registered with the SEC or listed for trading on any exchange. The foregoing descriptions of the Investors' Rights Agreement, the Support Agreements, the Lock-Up Agreements, and the CVR Agreement do not purport to be complete and are qualified in their entirety by reference to the full text of the Investors' Rights Agreement, the Support Agreements, the Lock-Up Agreements, and the CVR Agreement, which are filed as Exhibit 2, Exhibit 3, Exhibit 4, and Exhibit 5 respectively, 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. Form of Parent Stockholder Support Agreement (incorporated by reference to Exhibit A to Exhibit 2.1 to the Issuer's Current Report on Form 8-K (File No. 001-40287) filed with the SEC on August 7, 2023). Exhibit 4. Contingent Value Rights Agreement, dated August 4, 2023, by and between the Issuer and Computershare Trust Company N.A, as rights agent (incorporated by reference to Exhibit 10.1 to the Issuer's Current Report on Form 8-K (File No. 001-40287) filed with the SEC on August 7, 2023).