- EPI-321 is the first investigational therapy designed to silence DUX4 expression via epigenetic modulation

- FDA has granted Fast Track, Rare Pediatric Disease, and Orphan Drug Designation for EPI-321 in FSHD

Epicrispr Biotechnologies, a clinical-stage company pioneering gene-modulating therapies, today announced that the first patient has been dosed in its global first-in-human clinical trial of EPI-321, an investigational, one-time epigenetic editing therapy for facioscapulohumeral muscular dystrophy (FSHD).

FSHD is a progressive genetic disease that affects approximately 1 in 8,000 individuals worldwide, leading to skeletal muscle degeneration and severe loss of function. There are currently no approved disease modifying therapies for FSHD.

“For too long, individuals with FSHD have endured this progressive disease with no treatment options,” said Amber Salzman, Ph.D., Chief Executive Officer, Epicrispr Biotechnologies. “EPI-321 represents the start of a new chapter where we’re finally evaluating a therapy that targets the underlying cause of FSHD. We’re thrilled to dose our first patient, which is a milestone for our team and more importantly, a sign of hope for patients and families waiting for meaningful treatment options for this progressive neuromuscular disorder.”

“This is a deeply significant moment for the FSHD community,” said Mark Stone, CEO of the FSHD Society. “For decades, patients and families have carried the burden of a disease with no treatment that addresses its root cause. They’ve shown resilience, courage, and unwavering hope. The dosing of the first patient with EPI-321 represents more than scientific progress - it represents a turning point in the lives of those who have waited far too long. We commend Epicrispr for advancing a bold and innovative approach that brings new possibilities and real hope to families around the world.”

EPI-321 is an investigational, single dose, gene-modulating therapy designed to silence aberrant expression of DUX4 in skeletal muscle, a gene that is incorrectly activated within muscle cells in people living with FSHD, leading to progressive muscle degeneration. Delivered intravenously via a clinically validated AAV vector, EPI-321 has demonstrated robust suppression of DUX4 expression and protection of muscle tissue in preclinical models. EPI-321 has received FDA Fast Track, Rare Pediatric Disease, and Orphan Drug designations.

“Dosing the first patient in this clinical trial is a major moment for the FSHD community. EPI-321 is the first therapeutic candidate designed to target the root cause of the disease and silence DUX4 through epigenetic editing, offering a potentially transformative approach to halting disease progression in FSHD,” said Dr. Renata Shih, Principal Investigator at Rare Disease Research (RDR) in Atlanta. “This achievement reflects the outstanding teamwork and dedication of the entire RDR research staff and Epicrispr team, whose collaboration and commitment have been essential to advancing this important clinical trial. We are deeply grateful to everyone involved for their invaluable contributions.”

The company’s global first-in-human trial is evaluating the safety, tolerability, and pharmacodynamics of EPI-321 in adults with genetically confirmed FSHD. Initial data is expected in early 2026.

About Epicrispr Biotechnologies

Epicrispr Biotechnologies is a biotechnology company pioneering gene-modulating therapies, leading with treatments for neuromuscular diseases. The company’s proprietary Gene Expression Modulation System (GEMS) enables precise, durable control of gene expression, unlocking first-in-class treatments for previously untreatable conditions. Epicrispr’s lead program, EPI-321 is in clinical trials for FSHD, and the company is advancing additional gene-modulating therapies. Learn more at www.epicrispr.com or follow us on LinkedIn.

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