FDA delays till June decision to approve DMD treatment SRP-9001

A decision about the gene therapy was expected at the end of May

Margarida Maia, PhD avatar

by Margarida Maia, PhD |

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The U.S. Food and Drug Administration (FDA) has pushed back its decision on SRP-9001 (delandistrogene moxeparvovec), an experimental gene therapy for Duchenne muscular dystrophy (DMD).

A decision is now expected by June 22, according to a press release.

If the agency decides to approve SRP-9001, it’s expected to be available initially to children ages 4 to 5 who have a genetic diagnosis of DMD and are able to walk.

The application was filed last year by SRP-9001’s developer Sarepta Therapeutics and placed under priority review by the FDA, which shortened the review time from the usual 10 months to six.

While the decision was expected at the end of May, the FDA will require “modest additional time to complete the review, including final label negotiations and postmarketing commitment discussions,” the company said.

DMD is caused by mutations in DMD, a gene that carries instructions for making the protein dystrophin. The mutations disrupt the protein’s production, which works as a shock absorber and is key for muscle health.

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Proving SRP-9001’s clinical benefit

SRP-9001 is designed to deliver a copy of a gene into muscle cells that provides them with instructions for making a shorter, but working, version of dystrophin. It’s given as a single dose via infusion into the vein.

Earlier this month, an FDA advisory committee voted by a narrow margin for SRP-9001’s accelerated approval. While not binding, the FDA will consider the vote when it makes its decision.

An accelerated approval would mean the FDA decided SRP-9001 is likely to work well in people with DMD based on early clinical data that suggest a clinical benefit. If given the thumbs-up, the company would still be required to prove the clinical benefit through a confirmatory study. 

EMBARK (NCT05096221), a Phase 3 clinical study in many locations in the U.S. and abroad, is that proposed confirmation. It’s testing SRP-9001 against a placebo in boys with DMD, ages 4 to 7.

Top-line data are expected in the last quarter of the year. If it meets its goals, the FDA may consider a full approval for SRP-9001 and expand its use for DMD patients of all ages.

Ahead of SRP-9001’s possible approval, the Muscular Dystrophy Association has launched a Gene Therapy Support Network to offer resources and education about gene therapy for people who have neuromuscular diseases.