144 0001856514 XXXXXXXX LIVE 0001622229 COGENT BIOSCIENCES, INC. 001-38443 275 Wyman Street, 3rd Floor Waltham MA 02451 (617) 945-5576 JOHN ROBINSON Officer Common Morgan Stanley Smith Barney LLC Executive Financial Services

1 New York Plaza 8th Floor New York NY 10004

90000 3486276.00 142376529 12/26/2025 NASDAQ Common 12/17/2025 Performance Shares Issuer N 45000 12/17/2025 Not Applicable Common 12/17/2025 Performance Shares Issuer N 45000 12/17/2025 Not Applicable Y Sales that were executed on December 26, 2025 are being reported on this Form 144 filed on December 29, 2025 given December 26, 2025 was treated as federal holidays for EDGAR filing purposes. 12/26/2025 /s/ John Edward Robinson