X0206 3 2022-02-03 0 0001786205 Arcellx, Inc. ACLX 0001853723 SR ONE CAPITAL MANAGEMENT, LLC 985 OLD EAGLE SCHOOL ROAD SUITE 511 WAYNE PA 19087 0 0 1 0 0001848319 SR One Capital Fund I Aggregator LP 985 OLD EAGLE SCHOOL ROAD SUITE 511 WAYNE PA 19087 0 0 1 0 0001853724 SR ONE CAPITAL PARTNERS I, LP 985 OLD EAGLE SCHOOL ROAD SUITE 511 WAYNE PA 19087 0 0 1 0 0001867644 SR One Co-Invest II, LLC 985 OLD EAGLE SCHOOL ROAD SUITE 511 WAYNE PA 19087 0 0 1 0 0001595117 George Simeon 985 OLD EAGLE SCHOOL ROAD SUITE 511 WAYNE PA 19087 0 0 1 0 Series A Preferred Stock Common Stock 1550309 I See footnote Series B-1 Preferred Stock Common Stock 666651 I See footnote Series B-2 Preferred Stock Common Stock 533389 I See footnote Series C Preferred Stock Common Stock 649795 I See footnote Series C Preferred Stock Common Stock 433196 I See footnote All outstanding shares of Preferred Stock will automatically convert into shares of Common Stock at the Reporting Person's election and automatically upon the closing of the initial public offering of Arcellx, Inc. (the "Issuer"). The Preferred Stock has no expiration date. The reported securities are held directly by SR One Capital Fund I Aggregator, LP. SR One Capital Partners I, LP is the general partner of SR One Capital Fund I Aggregator, LP, and SR One Capital Management, LLC is the general partner of SR One Capital Partners I, LP. Simeon George is the managing member of SR One Capital Management, LLC. Each of SR One Capital Partners I, LP, SR One Capital Management, LLC and Mr. George may each be deemed to have shared power to vote or dispose of these shares, and each disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein. The reported securities are held directly by SR One Co-Invest II, LLC. SR One Co-Invest Manager II, LLC is the managing member of SR One Co-Invest II, LLC, and SR One Capital Management, LLC is the managing member of SR One Co-Invest Manager II, LLC. Simeon George is the managing member of SR One Capital Management, LLC. Each of SR One Co-Invest Manager II, LLC, SR One Capital Management, LLC and Mr. George may each be deemed to have shared power to vote or dispose of these shares, and each disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein. /s/ Simeon George, Member 2022-02-03 Simeon George, Member 2022-02-03 Simeon George, Member 2022-02-03 Simeon George, Managing Member 2022-02-03 Simeon George 2022-02-03