X0609 4 2026-09-08 0001789972 Cullinan Therapeutics, Inc. CGEM 0001838061 Michaelson Jennifer false C/O CULLINAN THERAPEUTICS, INC. ONE MAIN STREET, SUITE 1350 CAMBRIDGE MA 02142 false true false false Chief Scientific Officer true Common Stock 2026-09-08 4 M false 4000 4.30 A 166844 D Common Stock 2026-09-08 4 S false 8000 21.57 D 158844 D Stock Option (Right to Buy) 4.30 2026-09-08 4 M false 4000 0 D 2030-10-28 Common Stock 4000 78987 D Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on August 7, 2025. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $21.31 to $21.83. The Reporting Person undertakes to provide to the Issuer, any shareholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. 25% of the shares vested on July 4, 2020, and the remaining shares vested in 36 equal monthly installments thereafter. /s/ Jacquelyn Sumer, Attorney-in-Fact 2026-09-10