New milestones hit in MD trial testing treatment to turn off faulty gene

Epicrispr Biotechnologies announced it has completed enrollment and dosing in a Phase 1/2 clinical trial testing EPI-321, an experimental one-time epigenetic therapy for facioscapulohumeral muscular dystrophy (FSHD), the company said in a press release. The trial (NCT06907875) enrolled 12 adults across seven sites in the U.S., Australia, and New Zealand. Six participants received a low dose of 20 trillion vector genomes per kilogram and six received a higher dose of 40 trillion vg/kg, according to Epicrispr. The treatment uses an adeno-associated viral vector to deliver epigenetic modifiers designed to silence the overactive DUX4 gene without altering the DNA sequence. Interim data from three low-dose patients followed for six months showed increases in lean muscle mass ranging from approximately 0.5 to 1.3 pounds, with some individual muscles increasing up to 15% in lean volume, the company said. Those patients also showed improvements in strength and functionality at three months. Biomarker data suggest the therapy is silencing DUX4 as intended. No serious side effects have been reported. CEO Amber Salzman said the company plans to present additional data at the World Muscle Society Annual Congress in September and complete 12-month follow-up for all participants next year. The study's main goal is to assess safety over five years.