FDA Grants Sarepta Priority Review for DMD Gene Therapy

The U.S. Food and Drug Administration granted Sarepta Therapeutics priority review for SRP-9001, its gene therapy to treat ambulant individuals with Duchenne muscular dystrophy.

The agency has set a regulatory action date of May 29, 2023.

Duchenne muscular dystrophy (DMD) is a rare, fatal neuromuscular genetic disease that occurs in approximately one in every 3,500-5,000 newborn males worldwide. DMD is caused by a change or mutation in the gene that encodes instructions for dystrophin. Symptoms of DMD usually appear in infants and toddlers. Affected children may experience developmental delays such as difficulty in walking, climbing stairs or standing from a sitting position. As the disease progresses, muscle weakness in the lower limbs spreads to the arms and other areas. Most patients require full-time use of a wheelchair in their early teens, and then progressively lose the ability to independently perform activities of daily living such as using the restroom, bathing, and feeding. Eventually, increasing difficulty in breathing due to respiratory muscle dysfunction requires ventilation support, and cardiac dysfunction can lead to heart failure. The condition is universally fatal, and patients usually succumb to the disease in their twenties.

SRP-9001 is an investigational gene therapy for Duchenne being developed in partnership with Roche. Duchenne is characterized by a mutation in the dystrophin gene that results in the lack of dystrophin, which acts as a shock absorber for muscle at the membrane. SRP-9001 is designed to treat the proximate cause of Duchenne by delivering to muscle a gene that codes for a shortened, functional form of dystrophin. In addition to a wealth of pre-clinical evidence, the BLA for SRP-9001 included efficacy and safety data from Study SRP-9001-103 (also known as ENDEAVOR), as well as from Studies SRP-9001-101 and SRP-9001-102, and an integrated analysis across these three clinical studies comparing functional results to a propensity-score-weighted external control (EC). In clinical results from more than 80 treated patients, SRP-9001 has demonstrated positive results at multiple time points, including one-, two- and up to four-years after treatment, in addition to demonstrating a consistent safety profile.

In December 2019, Roche partnered with Sarepta to combine Roche’s global reach, commercial presence, and regulatory expertise with Sarepta’s gene therapy candidate for Duchenne to accelerate access to SRP-9001 for patients outside the United States.

In addition to Studies SRP-9001-101, SRP-9001-102 and SRP-9001-103, SRP-9001 is also being studied in EMBARK (Study SRP-9001-301), a global, randomized, double-blind, placebo-controlled clinical trial of SRP-9001 that has recruited 125 participants with Duchenne between the ages of 4 to 7. EMBARK is fully enrolled with results expected by the end of 2023. Sarepta has proposed EMBARK as the post-marketing confirmatory trial for SRP-9001.

“Duchenne is a relentlessly degenerative and invariably fatal disease, robbing children of muscle and function hourly and daily,” said Doug Ingram, president and CEO, Sarepta Therapeutics. “Our BLA submission for an accelerated approval, along with the FDA’s acceptance of that BLA for filing and review, is a tremendously important milestone in our effort to bring a potentially life-changing gene therapy to Duchenne patients as rapidly as possible and we look forward to working with the FDA through the review process.”

Author: Rare Daily Staff