PepGen Abandons Duchenne Program, Shifts Spotlight To Another Rare Disease Candidate

PepGen Inc. PEPG announced on Wednesday that it will focus on advancing its myotonic dystrophy type 1 (DM1) program, currently in Phase 2 clinical development.

The company voluntarily discontinued the development of PGN-EDO51 and intends to wind down all Duchenne muscular dystrophy (DMD)-)-related research and development activities.

The decision is based on the levels of dystrophin protein measured in the 10 mg/kg cohort of its CONNECT1-EDO51 study of PGN-EDO51 in DMD patients amenable to exon 51 skipping.

In the CONNECT1 study’s 10 mg/kg cohort (n=4), 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%).

Also Read: PepGen To Voluntarily Pause Mid-Stage Duchenne Muscular Dystrophy Study, Stock Falls

The safety profile of PGN-EDO51 continued to be generally favorable and all treatment-related adverse events were mild. No serious adverse events were reported in the study.

“We are disappointed by the dystrophin results observed in the 10 mg/kg dose cohort in CONNECT1, as it was our hope that we could improve upon existing therapies for patients in a more profound way,” said James McArthur, president and CEO of PepGen.

Paul Streck, executive vice president and head of R&D at PepGen, continued, “PGN-EDODM1, PepGen’s investigational drug in development for DM1, has already demonstrated robust target engagement after a single 10 mg/kg dose in patients that resulted in mean mis-splicing correction of 29% with a favorable emerging safety profile as of February 24, 2025, the most recent safety update.”

PepGen expects to report data from its FREEDOM-DM1 15 mg/kg cohort in patients with DM1 during the second half of 2025. FREEDOM is a Phase 1 single ascending dose, randomized, placebo-controlled clinical trial, with endpoints including safety, 28-day splicing correction, and functional benefit measures.

The company also expects to report data from the 5 mg/kg cohort of its FREEDOM2-DM1 study in DM1 patients in the first quarter of 2026. FREEDOM2 is a Phase 2 multiple ascending dose, randomized, placebo-controlled clinical trial with endpoints following four doses, including safety, splicing correction, and functional benefit measures.

Price Action: At the last check on Thursday, PEPG stock was down 6.69% at $1.47 during the premarket session.

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