X0306 4 2022-12-20 0001761918 Erasca, Inc. ERAS 0001599214 Chen Bihua C/O CORMORANT ASSET MANAGEMENT, LLC 200 CLARENDON STREET, 52ND FLOOR BOSTON MA 02116 true 0001583977 Cormorant Asset Management, LP 200 CLARENDON STREET 52ND FLOOR BOSTON MA 02116 true 0001618442 Cormorant Global Healthcare Master Fund, LP 200 CLARENDON STREET, 52ND FLOOR BOSTON MA 02116 true 0001747677 Cormorant Private Healthcare Fund II, LP 200 CLARENDON STREET, 52ND FLOOR BOSTON MA 02116 true Common Stock 2022-12-13 4 P 0 307692 6.5 A 10813246 I See Footnotes Stock Option (right to buy) 5.808 2031-04-11 Common Stock 166666 166666 D Stock Option (right to buy) 5.35 2023-06-22 2032-06-21 Common Stock 40000 40000 D Shares reported herein are held by Cormorant Global Healthcare Master Fund, LP (the "Master Fund"), Cormorant Private Healthcare Fund II, LP ("Fund II"), and a managed account (the "Account"). Cormorant Asset Management, LP ("Cormorant") serves as the investment manager of the Master Fund, Fund II, and the Account. Bihua Chen serves as manager of the general partner of Cormorant. Ms. Chen disclaims beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, and the filing of this Form 4 shall not be construed as an admission that Ms. Chen is the beneficial owner of any such shares for purposes of Section 16(a) of the Securities Exchange Act of 1934 or for any other purpose. Represents (i) 2,986,402 shares of Common Stock held by the Master Fund, (ii) 7,716,444 shares of Common Stock held by Fund II, and (iii) 110,400 shares of Common Stock held by the Account. Shares reported herein as purchased on December 9, 2022 were purchased by the Master Fund. Stock option grant for 166,666 shares, 41,667 shares of which become exercisable on 3/16/2022 and 124,999 shares of which become exercisable thereafter in equal monthly installments through 3/16/2025. Stock options granted to Bihua Chen, in her capacity as a director of the Issuer. /s/ Bihua Chen 2021-07-22 /s/ CORMORANT ASSET MANAGEMENT, LP By: Cormorant Asset Management GP, LLC, its General Partner, By: Bihua Chen, Managing Member 2021-07-22 /s/ CORMORANT GLOBAL HEALTHCARE MASTER FUND, LP, By: Cormorant Global Healthcare GP, LLC, its General Partner By: Bihua Chen, Managing Member 2021-07-22 /s/ CORMORANT PRIVATE HEALTHCARE FUND II, LP By: Cormorant Private Healthcare GP II, LLC, its General Partner By: Bihua Chen, Managing Member 2021-07-22