X0609 4 2026-09-28 0001768446 Climb Bio, Inc. CLYM 0001346824 RA CAPITAL MANAGEMENT, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 true false true false 0001315082 RA Capital Healthcare Fund LP false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0001780117 RA Capital Nexus Fund, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 0 0 0001825376 RA Capital Nexus Fund II, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 0 0 0001883840 RA Capital Nexus Fund III, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 0 0 0001384859 Kolchinsky Peter false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0001619841 Shah Rajeev M. false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0 Common Stock 2026-09-28 4 M 0 10000 3.46 A 10000 I See footnotes Common Stock 2026-09-28 4 M 0 10000 3 A 20000 I See footnotes Common Stock 2026-09-28 4 M 0 10000 7.89 A 30000 I See footnotes Common Stock 2026-09-28 4 M 0 40000 1.29 A 70000 I See footnotes Common Stock 3837101 I See footnotes Common Stock 1226497 I See footnotes Common Stock 483679 I See footnotes Common Stock 3671766 I See footnotes Common Stock 841087 I See footnotes Stock Option (Right to Buy) 3.46 2026-09-28 4 M 0 10000 0 D 2026-09-29 Common Stock 10000 0 I See footnotes Stock Option (Right to Buy) 3 2026-09-28 4 M 0 10000 0 D 2026-09-29 Common Stock 10000 0 I See Footnotes Stock Option (Right to Buy) 7.89 2026-09-28 4 M 0 10000 0 D 2026-09-29 Common Stock 10000 0 I See Footnotes Stock Option (Right to Buy) 1.29 2026-09-28 4 M 0 40000 0 D 2026-09-29 Common Stock 40000 0 I See Footnotes RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus Fund II, L.P. (the "Nexus Fund II"), RA Capital Nexus Fund III, L.P. (the "Nexus Fund III"), and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund II, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein. This option was granted to Andrew Levin pursuant to the Issuer's non-employee director compensation policy. Under Dr. Levin's arrangement with the Adviser, Dr. Levin held the option for the benefit of the Fund, the Nexus Fund, the Nexus Fund II, the Nexus Fund III, and the Account. Dr. Levin is obligated to turn over to the Adviser any stock received upon exercise of the option, which will offset advisory fees owed by the Fund to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the option and underlying common stock. These securities are held directly by Fund. These securities are held directly by the Nexus Fund. These securities are held directly by the Nexus Fund II. These securities are held directly by Nexus Fund III. These securities are held directly by the Account. Immediately exercisable. Breanna Celebi, an Analyst of the Adviser, serves on the Issuer's board of directors. /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 2026-09-30 /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P. 2026-09-30 /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC, the General Partner of RA Capital Nexus Fund, L.P. 2026-09-30 /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC, the General Partner of RA Capital Nexus Fund II, L.P. 2026-09-30 /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P. 2026-09-30 /s/ Peter Kolchinsky, individually 2026-09-30 /s/ Rajeev Shah, individually 2026-09-30