FDA Grants Rare Pediatric Disease Designation to Precision BioSciences for DMD Gene Editing Therapy

Rare Daily Staff

The U.S. Food and Drug Administration granted Rare Pediatric Disease Designation to Precision BioSciences for its PBGENE-DMD, an experimental gene editing therapy for the rare neuromuscular condition Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a progressive, degenerative muscle disease. It is caused by mutations in the DMD gene, which encodes dystrophin, a protein involved in muscle cell structure and signaling pathways. Without dystrophin, muscles throughout the body degenerate and become weak, eventually leading to loss of movement and independence, the need for breathing support, cardiomyopathy, and premature death.

PBGENE-DMD uses two complementary enzymes developed by Precision called ARCUS nucleases. The therapy is delivered through a one-time administration of a single adeno-associated virus (AAV) vector to excise exons 45–55 of the DMD gene. The aim is to restore near-full-length dystrophin protein within the body to improve functional outcomes. PBGENE-DMD is intended to address more than 60 percent of the DMD patient population.

In preclinical studies, PBGENE-DMD demonstrated the ability to target key muscle types involved in the progression of DMD and produced significant, durable functional improvements in a humanized DMD mouse model. PBGENE-DMD restored the body’s ability to produce near-full-length, functional dystrophin protein across multiple muscles, including cardiac tissue and various key skeletal muscle groups. In addition, PBGENE-DMD edited satellite muscle stem cells, which are believed to be critical for long-term durability and sustained functional improvement.

“The receipt of Rare Pediatric Disease Designation highlights the significant unmet need that necessitates new therapeutic options for boys living with DMD,” said Cindy Atwell, chief development and business officer at Precision BioSciences. “Our approach is designed to permanently edit a patient’s own DNA sequence, resulting in naturally produced, near-full-length dystrophin protein known to be functional in humans.”

The FDA grants Rare Pediatric Disease Designation to therapies targeting serious and life-threatening diseases that affect fewer than 200,000 people in the United States and primarily affect individuals under the age of 18.

The designation can make Precision eligible to receive a Priority Review Voucher upon FDA approval of PBGENE-DMD. The Priority Review Voucher program is designed to incentivize drug development for serious, rare pediatric diseases. If awarded, the original sponsor can redeem the voucher to receive FDA priority review for a different product.

The vouchers are potentially lucrative because they are transferable and can be sold. Recently, companies have sold these for around $150 million each. However, the program has expired, and pending legislation in Congress must be passed to renew it.