X0609 4 2026-06-18 0001835597 PepGen Inc. PEPG 0001346824 RA CAPITAL MANAGEMENT, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 true false true false 0001315082 RA Capital Healthcare Fund LP false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0001825376 RA Capital Nexus Fund II, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 0 0 0001384859 Kolchinsky Peter false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0001619841 Shah Rajeev M. false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 1 0 1 0 0 Stock Option (Right to Buy) 1.79 2026-06-18 4 A 0 34000 0 A 2036-06-17 Common Stock 34000 34000 I See Footnotes This option shall vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the Issuer's next Annual Stockholder Meeting, provided, however, that all vesting shall cease if Dr. Resnick ceases to serve as a director, unless the Issuer's Board of Directors determines that the circumstances warrant continuation of vesting. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus Fund II, L.P. (the "Nexus Fund II"), and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund II, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein. Under Dr. Resnick's arrangement with the Adviser, Dr. Resnick holds the option for the benefit of the Fund, the Nexus Fund II and the Account. Dr. Resnick is obligated to turn over to the Adviser any net cash or stock received upon exercise of the option, which will offset advisory fees owed by the Fund, the Nexus Fund II, and the Account to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the option and underlying common stock. Joshua Resnick, a Partner of the Adviser, serves on the Issuer's board of directors. /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 2026-06-22 /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P. 2026-06-22 /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC, the General Partner of RA Capital Nexus Fund II, L.P. 2026-06-22 /s/ Peter Kolchinsky, individually 2026-06-22 /s/ Rajeev Shah, individually 2026-06-22