Epicrispr Completes Dosing in First-in-Human EPI-321 Trial for Muscular Dystrophy

Epicrispr Biotechnologies announced completion of enrollment and dosing in the dose-escalation portion of its first-in-human trial of EPI-321, an AAV-delivered CRISPR-based epigenetic gene therapy for facioscapulohumeral muscular dystrophy (FSHD). All 12 patients were enrolled and dosed across two dose cohorts (2×10^13 and 4×10^13 vg/kg). EPI-321 works by re-methylating the D4Z4 region in skeletal muscle to silence the toxic DUX4 gene, rather than cutting DNA. Among evaluable patients, the company reported statistically significant increases in whole-body lean muscle volume by MRI, biomarker changes consistent with DUX4 suppression, favorable strength/functional outcomes, and a manageable safety profile with no serious adverse events reported to date. Additional data expected at the World Muscle Society Annual Congress in September 2026.