X0508 4 2024-05-21 0 0001761918 Erasca, Inc. ERAS 0001455228 Casdin Alexander W. C/O ERASCA, INC. 3115 MERRYFIELD ROW, SUITE 300 SAN DIEGO CA 92121 1 0 0 0 0 Common Stock 2024-05-21 4 P 0 80000 2.274 A 573974 D Common Stock 93750 I By spouse The open market purchase was completed by the Alexander W. Casdin Inheritance IRA. Mr. Casdin exercises voting and dispositive control over the securities held by such IRA and is therefore deemed to be a beneficial owner of securities owned by such IRA. Includes 80,000 shares held by Alexander W. Casdin Inheritance IRA. Mr. Casdin exercises voting and dispositive control over the securities held by such IRA and is therefore deemed to be a beneficial owner of securities owned by such IRA. /s/ Ebun Garner, attorney-in-fact 2024-05-22