X0508 4 2025-12-18 0001789972 Cullinan Therapeutics, Inc. CGEM 0001844824 SUMER JACQUELYN L C/O CULLINAN THERAPEUTICS, INC. ONE MAIN STREET, SUITE 1350 CAMBRIDGE MA 02142 false true false false Chief Legal Officer false Common Stock 2025-12-18 4 S false 3480 9.67 D 135432 D Sale of shares to cover personal income tax obligations upon vesting of restricted stock units. Includes 2,017 shares of common stock that the Reporting Person purchased pursuant to the Issuer's 2021 Employee Stock Purchase Plan for the purchase period of January 1, 2025 through June 30, 2025 that were exempt under both Rule 16b-3(d) and Rule 16b-3(c). /s/ Jacquelyn Sumer 2025-12-19