SCHEDULE 13D/A 0000921895-23-002457 0000918923 XXXXXXXX LIVE 2 Common Shares, no par value 11/20/2025 true 0001808158 760273102 Repare Therapeutics Inc.

7171 FREDERICK BANTING SUITE 270, BUILDING 2 SAINT-LAURENT A8 H4S 1Z9

JAMES KRATKY 415-525-8830 BVF PARTNERS L.P. 44 Montgomery St., 40th Floor San Francisco CA 94104 0000918923 N BIOTECHNOLOGY VALUE FUND L P a WC N DE 0.00 5309432.00 0.00 5309432.00 5309432.00 N 12.4 PN 0001803805 N BVF I GP LLC a AF N DE 0.00 5309432.00 0.00 5309432.00 5309432.00 N 12.4 OO 0001102444 N BIOTECHNOLOGY VALUE FUND II LP a WC N DE 0.00 4308573.00 0.00 4308573.00 4308573.00 N 10.0 PN 0001803806 N BVF II GP LLC a AF N DE 0.00 4308573.00 0.00 4308573.00 4308573.00 N 10.0 OO 0001660683 N Biotechnology Value Trading Fund OS LP a WC N E9 0.00 548938.00 0.00 548938.00 548938.00 N 1.3 PN 0001660684 N BVF Partners OS Ltd. a AF N E9 0.00 548938.00 0.00 548938.00 548938.00 N 1.3 CO 0001803809 N BVF GP HOLDINGS LLC a AF N DE 0.00 9618005.00 0.00 9618005.00 9618005.00 N 22.4 OO 0001055947 N BVF PARTNERS L P/IL a AF N DE 0.00 10333600.00 0.00 10333600.00 10333600.00 N 24.0 IA PN 0001056807 N BVF INC/IL a AF N DE 0.00 10333600.00 0.00 10333600.00 10333600.00 N 24.0 CO 0001233840 N LAMPERT MARK N a AF N X1 0.00 10333600.00 0.00 10333600.00 10333600.00 N 24.0 IN Common Shares, no par value Repare Therapeutics Inc. 7171 FREDERICK BANTING SUITE 270, BUILDING 2 SAINT-LAURENT A8 H4S 1Z9 Item 4 is hereby amended to add the following: On November 14, 2025, the Issuer entered into an Arrangement Agreement (the "Agreement") with XenoTherapeutics, Inc., a Massachusetts non-profit corporation ("Xeno"), Xeno Acquisition Corp., a Delaware corporation and wholly-owned subsidiary of Xeno ("Purchaser"), and solely for purposes of Section 9.15 thereof, XOMA Royalty Corporation, a Nevada corporation, pursuant to which Purchaser will acquire all of the issued and outstanding Shares (the holders of such Shares, the "Shareholders") of the Issuer (the "Transaction"). Under the terms of the Agreement, the Shareholders will receive a cash payment per Share that will be determined based upon the Issuer's cash balance immediately prior to the closing of the Transaction ("Closing") after deducting certain transaction costs, the aggregate amount of outstanding liabilities, and a transaction fee to Xeno. In addition, each Shareholder will also receive one non-transferable contingent value right (each, a "CVR") for each Share that will entitle the holder to receive a pro rata portion of potential cash payments. The cash payable at Closing is estimated by the Issuer to be approximately $1.82 per Share, exclusive of payments received pursuant to the CVR. The Transaction will be implemented by way of a court-approved plan of arrangement under the Business Corporations Act (Quebec) (such transaction, the "Arrangement"). On November 20, 2025, certain of the Reporting Persons entered into Voting and Support Agreements (the "Voting Agreements") with the Issuer pursuant to which such Reporting Persons agreed, among other things, to vote all voting securities of the Issuer beneficially owned by them in favor of the approval and adoption of the Arrangement and the transactions contemplated therein. The foregoing description of the Voting Agreements does not purport to be complete and is qualified in its entirety by reference to the full text of a form of the Voting Agreements, a copy of which is attached hereto as Exhibit 99.1 and incorporated herein by reference. Item 5(a) is hereby amended and restated to read as follows: The aggregate percentage of Shares reported owned by each person named herein is based on 42,985,755 Shares outstanding as of November 14, 2025, which is the total number of Shares outstanding as reported in Exhibit 2.1 to the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission on November 17, 2025. As of the close of business on the date hereof, (i) BVF beneficially owned 5,309,432 Shares, representing percentage ownership of approximately 12.4% of the Shares outstanding, (ii) BVF2 beneficially owned 4,308,573 Shares, representing percentage ownership of approximately 10.0% of the Shares outstanding, and (iii) Trading Fund OS beneficially owned 548,938 Shares, representing percentage ownership of approximately 1.3% of the Shares outstanding. BVF GP, as the general partner of BVF, may be deemed to beneficially own the 5,309,432 Shares beneficially owned by BVF, representing percentage ownership of approximately 12.4% of the Shares outstanding. BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 4,308,573 Shares beneficially owned by BVF2, representing percentage ownership of approximately 10.0% of the Shares outstanding. Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 548,938 Shares beneficially owned by Trading Fund OS, representing percentage ownership of approximately 1.3% of the Shares outstanding. BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 9,618,005 Shares beneficially owned in the aggregate by BVF and BVF2, representing percentage ownership of approximately 22.4% of the Shares outstanding. Partners, as the investment manager of BVF, BVF2 and Trading Fund OS and the Partners Managed Account, and the sole member of Partners OS, may be deemed to beneficially own the 10,333,600 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, including 166,657 Shares held in the Partners Managed Account, representing percentage ownership of approximately 24.0% of the Shares outstanding (less than 1% of the Shares outstanding are held in the Partners Managed Account). BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 10,333,600 Shares beneficially owned by Partners, representing percentage ownership of approximately 24.0% of the Shares outstanding. Mr. Lampert, as the sole director and officer of BVF Inc., may be deemed to beneficially own the 10,333,600 Shares beneficially owned by BVF Inc., representing percentage ownership of approximately 24.0% of the Shares outstanding. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account. Item 6 is hereby amended to add the following: On November 20, 2025, certain of the Reporting Persons entered into the Voting Agreements, as defined and described in Item 4 above. A form of Voting Agreement is attached hereto as Exhibit 99.1. Item 7 is hereby amended to add the following exhibit: 99.1 - Form of Voting and Support Agreement, dated November 20, 2025. BIOTECHNOLOGY VALUE FUND L P /s/ Mark N. Lampert 11/24/2025 BVF I GP LLC /s/ Mark N. Lampert 11/24/2025 BIOTECHNOLOGY VALUE FUND II LP /s/ Mark N. Lampert 11/24/2025 BVF II GP LLC /s/ Mark N. Lampert 11/24/2025 Biotechnology Value Trading Fund OS LP /s/ Mark N. Lampert 11/24/2025 BVF Partners OS Ltd. /s/ Mark N. Lampert 11/24/2025 BVF GP HOLDINGS LLC /s/ Mark N. Lampert 11/24/2025 BVF PARTNERS L P/IL /s/ Mark N. Lampert 11/24/2025 BVF INC/IL /s/ Mark N. Lampert 11/24/2025 LAMPERT MARK N /s/ Mark N. Lampert 11/24/2025