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Sarepta asks FDA to approve first gene therapy for Duchenne muscular dystrophy

Sarepta Therapeutics has asked the Food and Drug Administration to approve its gene therapy for Duchenne muscular dystrophy under accelerated review, the company said Thursday.

The biotechnology company’s application for SRP-9001, also known as delandistrogene moxeparvovec, is primarily based on biological data — specifically the ability of the gene therapy to boost production of a form of the protein that’s missing in Duchenne patients.

The submission comes a year earlier than many investors were expecting, until Sarepta revealed sped-up filing plans in late July. The company has a Phase 3 trial underway called EMBARK, that compares SRP-9001 to a placebo, with data due next year. However, based on feedback from FDA reviewers, Sarepta said the biological data, along with results from previous studies that evaluated the therapy’s safety and effectiveness in helping patients’ muscular function, are sufficient for an application.

“Waiting for the EMBARK readout and then compiling a [full approval application] … would extend the timeline to get this therapy to the children that are waiting for it by as much as a year,” Sarepta CEO Doug Ingram said during an earnings call on Aug. 2. “And given the feedback we’ve received from the agency, clearly the more appropriate and, frankly, ethical thing to do is submit [an application] for an accelerated approval.”

The therapy has had a mixed development history. Initial findings in some of the first patients dosed with SRP-9001 in 2018 were positive and inflated Sarepta’s market valuation to record highs. But they were followed by disappointment when a manufacturing problem led to a clinical hold.

An early effectiveness trial later missed its key goal, raising questions over whether the treatment helps patients enough to gain FDA approval.

Along the way, Sarepta has faced competition from Pfizer and Solid Biosciences, which have fallen behind Sarepta’s clinical work.

Sarepta has three other muscular dystrophy drugs on the market, for patients with specific genetic mutations. All have won accelerated approvals based on biological data. So far none of those approvals have been confirmed by trials that measure whether the drugs improve patient outcomes, although the company is working on gathering that data.

That track record has made Sarepta an example for policymakers who want to reform the FDA’s accelerated review program, such as by having accelerated approvals expire after several years or requiring that confirmatory trials be underway before the FDA grants accelerated approval.