Precision BioSciences Receives FDA Orphan Drug Designation for AAV Gene Therapy PBGENE-DMD

DURHAM, N.C. – July 23, 2025 – Precision BioSciences, Inc. (Nasdaq: DTIL), a clinical-stage gene editing company, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to PBGENE-DMD. This in vivo gene editing therapy, developed using Precision’s proprietary ARCUS® platform, is designed for the treatment of Duchenne muscular dystrophy (DMD).

The ODD signifies the significant unmet medical need for DMD, a rare genetic disorder affecting fewer than 200,000 people in the United States. This designation provides Precision BioSciences with valuable benefits, including financial incentives for clinical development and potential for seven years of market exclusivity if the drug receives ultimate approval for DMD. This follows their recent FDA Rare Pediatric Disease (RPD) designation for PBGENE-DMD.

About PBGENE-DMD:

PBGENE-DMD represents a novel therapeutic approach aimed at restoring near full-length dystrophin protein within the body to improve functional outcomes for DMD patients.

• The approach uses two complementary ARCUS nucleases delivered via a one-time administration in a single Adeno-Associated Virus (AAV) vector to precisely excise exons 45-55 of the dystrophin gene. The use of AAV as a gene delivery vehicle is crucial for this in vivo strategy.
• Its goal is to restore near full-length dystrophin protein in vivo.
• This approach is intended to address up to 60% of the DMD patient population.

Promising Preclinical Data:

In preclinical studies, PBGENE-DMD has demonstrated:

• The ability to effectively target key muscle types critical to DMD progression, facilitated by the AAV delivery.
• Significant and durable functional improvements in a humanized DMD mouse model.
• Restoration of the body’s capacity to produce near full-length functional dystrophin protein across multiple muscle groups, including cardiac tissue and various skeletal muscles.
• Editing of satellite muscle stem cells, a factor believed to be crucial for long-term durability and sustained functional improvement.

Path Towards the Clinic:

Precision BioSciences is actively engaged in the final IND-enabling toxicology studies for PBGENE-DMD. The company is collaborating closely with leading DMD clinicians to design a first-in-human trial. Clinical-grade material for the trial is currently in preparation, with initial clinical data anticipated in 2026. Precision BioSciences continues its active dialogue with the FDA as the program progresses towards further regulatory milestones.