SCHEDULE 13G/A 0001104659-24-088367 0001346824 XXXXXXXX LIVE 4 Common Stock, par value $0.0001 per share 06/30/2025 0002006986 Adagio Medical Holdings, Inc. 00534B100 26051 Merit Circle, Suite 102 Laguna Hills CA 92653 Rule 13d-1(c) RA Capital Management, L.P. DE 0.00 1200000.00 0.00 1200000.00 1200000.00 7.2 IA PN This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025. Peter Kolchinsky X1 0.00 1200000.00 0.00 1200000.00 1200000.00 7.2 HC IN This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025. Rajeev Shah X1 0.00 1200000.00 0.00 1200000.00 1200000.00 7.2 HC IN This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025. RA Capital Healthcare Fund, L.P. DE 0.00 1140000.00 0.00 1140000.00 1140000.00 6.9 PN This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025. Adagio Medical Holdings, Inc. 26051 Merit Circle, Suite 102, Laguna Hills, CA, 92653. The names of the persons filing this report (collectively, the "Reporting Persons") are: RA Capital Management, L.P. ("RA Capital") Peter Kolchinsky Rajeev Shah RA Capital Healthcare Fund, L.P. (the "Fund") The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G. The address of the principal business office of each of the Reporting Persons is: c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston MA 02116 RA Capital and the Fund are Delaware limited partnerships. Dr. Kolchinsky and Mr. Shah are United States citizens. Y Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of shares of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. The Reporting Persons' ownership of the Issuer's securities includes (i) 1,140,000 shares of common stock issuable upon the exercise of immediately exercisable warrants (the "Warrants") directly held by the Fund, and (ii) 60,000 shares of common stock issuable upon the exercise of immediately exercisable Warrants directly held by RA Capital Nexus Fund II, L.P. (the "Nexus Fund II"). RA Capital Healthcare Fund GP, LLC is the general partner of the Fund and RA Capital Nexus Fund II GP, LLC is the general partner of the Nexus Fund II. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for each of the Fund and the Nexus Fund II and may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer held by the Fund or the Nexus Fund II. Each of the Fund and the Nexus Fund II has delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in its portfolio, including the shares of the Issuer's common stock reported herein. Because each of the Fund and the Nexus Fund II has divested itself of voting and investment power over the reported securities it holds and may not revoke that delegation on less than 61 days' notice, each of the Fund and the Nexus Fund II disclaims beneficial ownership of the securities it holds for purposes of Section 13(d) of the Act and therefore disclaims any obligation to report ownership of the reported securities under Section 13(d) of the Act. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of the securities reported in this Schedule 13G other than for the purpose of determining their obligations under Section 13(d) of the Act, and the filing of this Schedule 13G shall not be deemed an admission that either RA Capital, Dr. Kolchinsky, or Mr. Shah is the beneficial owner of such securities for any other purpose. Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. The percentage set forth in Row 11 of each Reporting Person's cover page is based upon the sum of: (i) 15,381,565 shares of the Issuer's common stock outstanding as of June 30, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on August 14, 2025 and (ii) 1,200,000 shares of common stock issuable upon the exercise of the Warrants. Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit 99.1 to Schedule 13G/A filed on May 15, 2025) RA Capital Management, L.P. /s/ Peter Kolchinsky 08/26/2025 Peter Kolchinsky /s/ Peter Kolchinsky 08/26/2025 Rajeev Shah /s/ Rajeev Shah 08/26/2025 RA Capital Healthcare Fund, L.P. /s/ Peter Kolchinsky 08/26/2025