X0508 4 2025-12-04 0 0001253689 CRESCENT BIOPHARMA, INC. CBIO 0001802528 Fairmount Funds Management LLC 200 BARR HARBOR DRIVE SUITE 400 WEST CONSHOHOCKEN PA 19428 1 0 1 0 0001769651 Fairmount Healthcare Fund II L.P. 200 BARR HARBOR DRIVE SUITE 400 WEST CONSHOHOCKEN PA 19428 1 0 1 0 0001830177 Kiselak Tomas 200 BARR HARBOR DRIVE SUITE 400 WEST CONSHOHOCKEN PA 19428 1 0 1 0 0001663607 Harwin Peter Evan 200 BARR HARBOR DRIVE SUITE 400 WEST CONSHOHOCKEN PA 19428 1 0 1 0 0 Ordinary Shares 2025-12-04 4 P 0 1360000 13.41 A 2747866 I By Fairmount Healthcare Fund II L.P. Pre-Funded Warrant (Right to Buy) 0.001 2025-12-04 4 P 0 131434 13.409 A Ordinary Shares 131434 1768140 I By Fairmount Healthcare Fund II L.P. Fairmount Funds Management LLC ("Fairmount") is the investment manager for Fairmount Healthcare Fund II L.P. The managers of Fairmount are Peter Harwin and Tomas Kiselak. Fairmount, Mr. Harwin, and Mr. Kiselak disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein. The Pre-Funded Warrants have no expiration date and are exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the Pre-Funded Warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of outstanding shares of common stock of the Issuer immediately after giving effect to such exercise. Fairmount may be deemed a director by deputization of Issuer by virtue of the fact that Peter Harwin serves on the board of directors of the Issuer and is a manager of Fairmount. /s/ Tomas Kiselak, Managing Member of Fairmount Funds Management LLC 2025-12-08 /s/ Tomas Kiselak, Managing Member of Fairmount Healthcare Fund II, L.P. 2025-12-08 /s/ Tomas Kiselak 2025-12-08 /s/ Peter Harwin 2025-12-08