Sarepta Therapeutics Inc.’s gene therapy received expanded US approval to include more children with a deadly muscle disease, expanding the market for a controversial treatment that still hasn’t proved its benefit in clinical trials.
Sarepta shares surged 36% in extended trading at 5:51 p.m. in New York.
The drug’s approval was widened for use in patients who are at least 4 years of age with Duchenne muscular, Sarepta said in a statement. The agency granted a traditional approval for patients who can still walk. It also granted an accelerated approval for patients who can’t walk, meaning the company will need to perform a confirmatory trial.
The therapy, called Elevidys, has highlighted a type of approval that’s become the center of debate. The treatment, which is priced at $3.2 million, was initially cleared through an accelerated approval pathway, a regulatory shortcut designed to get drugs for devastating diseases to market quickly, often based on preliminary data. If a confirmatory trial doesn’t show the drug provides a clinical benefit, the FDA can pull it from the market. While such fast approvals may help some desperate patients, critics say the system sometimes allows unproven drugs to stay on the market for years.
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The FDA initially cleared Elevidys last year to treat 4- and 5-year-olds, the age group that appeared to gain the most benefit in studies. That earlier FDA decision was an attempt to strike a middle ground in response to questions about the treatment’s effectiveness, and Sarepta has been working since to gain clearance for broader use.
In October, Sarepta said its confirmatory trial failed to clearly slow the disease in a yearlong study of 125 young children. But secondary measures of patients’ movement in the trial were positive, according to the drugmaker, and the company filed with US regulators for expanded, full approval.
Duchenne muscular dystrophy primarily occurs in about 1 in 3,500 male births worldwide. Caused by defects in a protein called dystrophin that helps keep muscle cells intact, the disease leads to severe muscle weakening and atrophy. Most patients die in their 20s, though some are living longer thanks to various treatment options, like steroids and other approved treatments that target a certain genetic mutation.
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Sarepta sells other drugs for the disease that require regular IV infusions. Gene therapies such as Elevidys, on the other hand, are one-time treatments that can provide long-lasting benefits. Despite being cleared for only a narrow group of children, Elevidys is one of the most successful therapies to hit the market.
In June, a gene therapy from Pfizer Inc. failed to improve motor function in boys with Duchenne, jeopardizing the future of a medicine that could have been a competitor to Sarepta’s treatment
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