Independent Data and Safety Monitoring Board (DSMB) has recommended advancing the ongoing Phase 2 FREEDOM2-DM1 study evaluating PGN-EDODM1 in participants with myotonic dystrophy type 1 (DM1) into the third and highest multiple ascending dose (MAD) cohort of 12.5 mg/kg, with no recommended changes to the study protocol. The DSMB also recommended dose escalation in the open-label extension (OLE) study from 5 mg/kg to 10 mg/kg. Notably, 6 of 8 participants from the 5 mg/kg FREEDOM2 cohort have elected to enroll in the OLE, bringing total OLE enrollment to 16 participants. The recommendation followed a review of available safety data from the fully enrolled 10 mg/kg MAD cohort and the OLE study.

PGN-EDODM1 remains generally well-tolerated, with no serious adverse events or dose-limiting toxicities reported in FREEDOM2 or the OLE to date. Repeat dosing at both the 5 mg/kg and 10 mg/kg dose levels shows no evidence of cumulative toxicity, and no treatment discontinuations were reported in FREEDOM2 or the OLE.

"The DSMB's recommendation to advance FREEDOM2 into the highest planned dose level in the study and escalate dosing in the OLE supports the encouraging safety profile of PGN-EDODM1 following multiple months of treatment," said James McArthur, PhD, President and Chief Executive Officer of PepGen. "In the FREEDOM2 study, 7 of 8 participants in the 10 mg/kg cohort have now completed dosing. We look forward to reporting additional safety, splicing and functional data from FREEDOM2 as we continue to evaluate the potential of PGN-EDODM1 to address the root cause of disease across multiple organ systems."

The Company expects to report results from the fully enrolled 10 mg/kg FREEDOM2 cohort in November. Results from the 12.5 mg/kg cohort are expected in the first half of 2027, at which time PepGen plans to engage with regulators in an end of Phase 2 meeting to discuss plans for the registrational program. The Company also expects to provide an update from the OLE study by early January.