Sarepta to Ask FDA to Approve DMD Gene Therapy SRP-9001

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Sarepta Therapeutics plans to ask the U.S. Food and Drug Administration (FDA) to grant accelerated approval to the company’s experimental gene therapy SRP-9001 for people with Duchenne muscular dystrophy (DMD) who are able to walk.

“We are delighted to confirm that based on the feedback we received following a thorough and in-depth review, we intend to submit a BLA [Biologics License Application] for our SRP-9001 gene therapy to treat Duchenne muscular dystrophy this fall,” Doug Ingram, Sarepta’s president and CEO, said in a press release. “We look forward to a collaborative review commencing this year and running through the first half of 2023.”

The FDA’s accelerated approval pathway allows it to permit the sale of therapies for serious conditions based on early clinical data that suggest they are probably effective. If SRP-9001 is given accelerated approval, the therapy’s developers (Sarepta and Roche) would be required to conduct additional testing to prove its clinical effectiveness. The company did not specify which data will be included in the upcoming BLA.

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Sustained Gains for DMD Boys Evident in SRP-9001 Trials: Sarepta

“Guided by rigorous science and productive regulatory discussions, our goal is to move with the urgency desperately needed by the patient community, and our upcoming BLA filing for SRP-9001 serves that goal,” Ingram said.

In DMD, genetic mutations render the body unable to make dystrophin, a protein needed to maintain muscle health. SRP-9001 (delandistrogene moxeparvovec) is designed to deliver a gene encoding micro-dystrophin, a shortened but functional version of this protein, to muscle cells. The therapy delivers its genetic cargo using a specially designed viral vector.

Data from a proof-of-concept Phase 1/2 clinical trial called Study 101 (NCT03375164) — which tested a single dose of the experimental gene therapy in four boys with DMD ages 4 to 6 at the time of dosing — indicated the therapy improved motor and walking function more than three years after dosing.

A Phase 2 trial called Study 102 (NCT03769116), which tested SRP-9001 in 41 boys with DMD ages 4 to 7, also indicated the treatment improved motor function.

Sarepta is running a Phase 3 clinical study called EMBARK (NCT05096221) to further evaluate the treatment. The trial is open to boys, ages 4 to 7, who are able to walk and are on a stable dose of daily corticosteroids. Recruitment is ongoing at more than 30 locations across the U.S., Europe, Hong Kong, and Taiwan.

Participants will be given a single infusion of either SRP-9001 or a placebo. After a year, those given a placebo will be given an infusion of SRP-9001, and vice versa. The study’s main goal is to assess the treatment’s effect on motor function as measured via the North Star Ambulatory Assessment (NSAA).

The FDA has already awarded SRP-9001 its fast track designation, which is intended to speed up the review of applications for experimental therapies designed to fill an unmet need for treating serious conditions. The FDA has also given the therapy rare pediatric disease and orphan drug designations.