– PGN-EDO51 did not achieve target dystrophin levels in CONNECT1-EDO51 trial; Company to discontinue development of DMD programs –

– PGN-EDO51 at 10 mg/kg was generally well tolerated; all treatment-related adverse events were mild –

– DM1 program on track to read out FREEDOM-DM1 15 mg/kg cohort in second half of 2025 and FREEDOM2-DM1 5 mg/kg cohort in Q1 2026 –

PepGen Inc. (NASDAQ:PEPG), a clinical-stage biotechnology company advancing the next generation of oligonucleotide therapies, today announced that based on the levels of dystrophin protein measured in the 10 mg/kg cohort of its CONNECT1-EDO51 study investigating PGN-EDO51 in Duchenne muscular dystrophy (DMD) patients amenable to exon 51 skipping, the Company will focus on advancing its promising myotonic dystrophy type 1 (DM1) program currently in Phase 2 clinical development. The Company is voluntarily discontinuing development of PGN-EDO51 and intends to wind down all DMD-related research and development activities.

In the 10 mg/kg cohort (n=4) of the CONNECT1 study, PGN-EDO51 increased exon 51 skipped transcripts to 4.26% (a mean increase of 3.5%); however, total dystrophin only increased to 0.59% of normal levels (a mean increase of 0.36%). The safety profile of PGN-EDO51 continued to be generally favorable and all treatment-related adverse events were mild in nature. No serious adverse events were reported in the study.