X0609 4 2026-08-03 0002130606 Obsidian Therapeutics, Inc. OBX 0001733077 ROSS ROBERT W. false C/O OBSIDIAN THERAPEUTICS, INC. 1030 MASSACHUSETTS AVE CAMBRIDGE MA 02138 true false false false false Stock Option (Right to Buy) 12.00 2026-08-03 4 A false 37653 0 A 2036-08-02 Common Stock 37653 37653 D The shares underlying this option shall vest and become exercisable upon the earlier of (i) the one-year anniversary of the grant date or (ii) the date of the Issuer's annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service with the Issuer on such vesting date. /s/ Gabriela Morales-Rivera, Attorney-in-Fact 2026-08-05