First Patient Dosed in Clinical Trial for Epicrispr Biotechnologies’ FSHD AAV Gene Therapy

SOUTH SAN FRANCISCO, CA-Aug 6th, 2025– In a landmark moment for the facioscapulohumeral muscular dystrophy (FSHD) community, Epicrispr Biotechnologies has announced that the first patient has been dosed in its global clinical trial for EPI-321. This investigational, one-time epigenetic editing therapy is the first of its kind to be evaluated in humans for FSHD, a progressive genetic disease with no approved treatments that address its underlying cause.

A Novel Approach to Treating FSHD

FSHD is a devastating and progressive condition that affects approximately 1 in 8,000 people globally, leading to the degeneration of skeletal muscle and significant loss of function. The disease is caused by the incorrect activation of the DUX4 gene in muscle cells.

EPI-321 is a gene-modulating therapy designed to specifically silence the aberrant DUX4 expression through epigenetic modulation. This method works by controlling gene expression without altering the DNA sequence itself. The therapy is delivered intravenously using an adeno-associated virus (AAV) vector. AAVs are a common and safe type of virus used in gene therapy as a vehicle to deliver genetic material into a patient’s cells. Preclinical studies showed that EPI-321 could effectively suppress DUX4 expression and protect muscle tissue.

A Sign of Hope for the FSHD Community

The dosing of the first patient marks a “deeply significant moment,” according to Mark Stone, CEO of the FSHD Society, who emphasized that patients have waited decades for a treatment that targets the root cause of the disease. Epicrispr Biotechnologies CEO, Amber Salzman, Ph.D., echoed this sentiment, calling the therapy “a sign of hope for patients and families waiting for meaningful treatment options.”

The global trial will evaluate the safety, tolerability, and pharmacodynamics of EPI-321 in adults with genetically confirmed FSHD. The company expects to release initial data in early 2026. The FDA has granted EPI-321 Fast Track, Rare Pediatric Disease, and Orphan Drug designations, reflecting its potential to address a significant unmet medical need.