Long-term PGN-EDODM1 extension for people with myotonic dystrophy type 1

An Open-Label Extension Study Evaluating Safety and Pharmacokinetics in Participants With Myotonic Dystrophy Type 1 (FREEDOM-OLE)

This open-label extension will try continued PGN-EDODM1 in people with myotonic dystrophy type 1 who completed a prior PGN-EDODM1 study to see how safe and tolerable it is over time.

Quick facts

• Phase: PHASE2
• Study type: Interventional
• Enrollment: 48 (estimated)
• Sex: All
• Sponsor: PepGen Inc (industry)
• Locations: 3 sites (Calgary, Alberta and 2 other locations)
• Trial ID: NCT07220603 on ClinicalTrials.gov

What this trial studies

This open-label extension enrolls participants with myotonic dystrophy type 1 who previously completed a PGN-EDODM1 trial to collect longer-term safety and tolerability data. Participants will continue to receive PGN-EDODM1 and undergo regular clinical visits, laboratory testing, and adverse event monitoring. The protocol excludes people with clinically significant abnormal labs at screening or recent use of other investigational products. The study is conducted at multiple Canadian sites and focuses on safety outcomes rather than efficacy endpoints.

Who should consider this trial

Good fit: Ideal candidates are people with myotonic dystrophy type 1 who completed a prior PGN-EDODM1 study and meet current screening labs and medication restrictions.

Not a fit: People who have not participated in a prior PGN-EDODM1 study, who have clinically significant abnormal screening labs, or who recently used other investigational products are unlikely to be eligible or benefit from this extension.

Why it matters

Potential benefit: If successful, the study could demonstrate that PGN-EDODM1 is safe to use long-term in people with DM1 and support continued development and access.

How similar studies have performed: Some related oligonucleotide and gene-targeting approaches in DM1 have shown early promise, but PGN-EDODM1 long-term data are limited and this extension is largely confirmatory for safety.

Eligibility criteria

Inclusion Criteria:

* Participant has completed a prior study with PGN-EDODM1

Exclusion Criteria:

* Abnormal laboratory tests at screening considered clinically significant by the Investigator
* Use of an investigational drug (other than PGN-EDODM1), device, or product, within 30 days or 5 half-lives of the study drug (whichever is longer) prior to study entry

Where this trial is running

Calgary, Alberta and 2 other locations

• University of Calgary — Calgary, Alberta, Canada (RECRUITING)
• Ottawa Hospital Research Institute — Ottawa, Ontario, Canada (RECRUITING)
• CIUSSS du Saguenay-Lac-Saint-Jean — Saguenay, Canada (RECRUITING)

Study contacts

• Study coordinator: PepGen Patient Advocacy

Conditions: Myotonic Dystrophy 1, DM1, Myotonic Dystrophy, PepGen, PGN-EDODM1, Myotonic Muscular Dystrophy, Steinhert's Disease, Myotonic Dystrophies