SCHEDULE 13D/A

PEPGEN INC

Common stock, par value $0.0001 per share · CUSIP: 713317105

Event date: 2025-09-26

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• RA Capital Management, L.P.Reported CIK 0001346824

  Shares: 20,099,753.00 · Class: 29.2%

• Peter KolchinskyReported CIK 0001384859

  Shares: 20,099,753.00 · Class: 29.2%

• Rajeev ShahReported CIK 0001619841

  Shares: 20,099,753.00 · Class: 29.2%

• RA Capital Healthcare Fund, L.P.Reported CIK 0001315082

  Shares: 18,554,273.00 · Class: 27.0%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.