PepGen Shares Trade Up 180% on Positive Results from FREEDON-DM1 Trial to Treat Myotonic Dystrophy Type 1

The clinical stage biotechnology company focused on the advancement of next generation of oligonucleotide therapies to treat severe neuromuscular and neurological diseases, PepGen Inc. (PEPG) announced positive initial clinical data from its FREEDOM-DM1 Phase 1 trial evaluating PGN-EDODM1 for myotonic dystrophy type 1 (DM1). Results from the 5 and 10 mg/kg dose cohorts showed significant dose-dependent splicing correction, with the 10 mg/kg group achieving a 29.1% correction at 28 days post-dose—surpassing previous multi-dose trials.

PGN-EDODM1 demonstrated a favorable safety profile, with most adverse events being mild or moderate. One serious adverse event of abdominal pain was reported but may have been influenced by an off-label medication. While functional improvements were not yet observed, the company anticipates benefits with repeat dosing.

PepGen plans to release data from the 15 mg/kg cohort in late 2025 and from the FREEDOM2 5 mg/kg cohort in early 2026, aiming to further validate PGN-EDODM1’s potential as a breakthrough DM1 treatment.

“These results far exceeded our expectations for splicing correction following a single dose of PGN-EDODM1. Mis-splicing is the underlying cause of DM1 pathology, and we believe the mean splicing correction observed at 28 days following a single dose of PGN-EDODM1 at 10 mg/kg in the FREEDOM clinical trial surpasses those reported to date in multi-dose clinical trials of up to nine months in duration in patients with DM1. We believe this is a strong indicator of our EDO technology’s potential to deliver therapeutic oligonucleotides to the nucleus and PGN-EDODM1’s potential to address the underlying cause of disease,” said James McArthur, PhD, President and CEO of PepGen. “We believe these results provide initial validation of PGN-EDODM1’s ability to selectively bind the pathogenic CUG-repeat DMPK RNA and we look forward to evaluating PGN-EDODM1 with more doses over longer time periods in our FREEDOM2-DM1 multiple ascending dose study. Based on these initial results, we aim to build on the significant correction of mis-splicing observed in this single-dose study to potentially provide improved functional benefit for patients who currently have no available approved therapeutic options.”