X0508 4 2025-12-26 0001622229 Cogent Biosciences, Inc. COGT 0001856514 Robinson John Edward C/O COGENT BIOSCIENCES, INC. 275 WYMAN STREET, 3RD FLOOR WALTHAM MA 02451 false true false false Chief Scientific Officer false Common Stock 2025-12-26 4 S false 90000 38.74 D 140002 D The price reported above is a weighted average price. The shares were sold in multiple transactions at prices ranging from $38.51 to $39.01, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder 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. Includes previously reported shares of common stock underlying restricted stock units granted to the Reporting Person, which are subject to certain vesting conditions. /s/ Evan D. Kearns, Attorney-in-Fact 2025-12-30