Sarepta rockets up after FDA approves its controversial Duchenne drug

After years of fierce debate in a seesaw battle over the fate of Sarepta’s Duchenne muscular dystrophy drug eteplirsen, the FDA has granted the drug conditional approval in the US, making this the first drug OK’d to treat the lethal disease.

Janet Woodcock

Janet Woodcock

The approval comes with the threat of swift retribution, though, if investigators fail to follow through with positive data from a bigger study. The agency’s statement includes a requirement that Sarepta will now have to confirm that the drug actually works as designed, spurring production of dystrophin in a way that can improve motor function in the 13% of patients amenable to exon 51 skipping. And the agency says that it may withdraw its OK without that data.

For now, though, Sarepta will move fast to start marketing the drug.

The agency’s decision came months after a panel of outside experts voted against an approval and FDA insiders, notably Ron Farkas, who recently left the agency, rejected the biotech’s argument at every turn this year. Parents and patients, though, turned out in the hundreds to voice their full support for eteplirsen, mounting a lobbying campaign that would recruit a long list of elected officials as well as physicians who treat this disease.

Sarepta’s $SRPT share price, which has been on a roller coaster ride at every twist and turn in the eteplirsen saga, ripped up 81% on the news. The drug will now be sold as Exondys 51.

The drug, though, will remain controversial. The agency’s Janet Woodcock overruled others in the FDA in giving this drug a green light, including Ellis Unger, the director of the Office of Drug Evaluation, who protested against Woodcock’s decision. And while the drug has its avowed supporters, a legion of critics has noted that Sarepta never provided the data needed to win an approval, with Woodcock seen as caving to the lobbying campaign in a way that would likely dog the agency for years to come.

The big debate over this drug centered on its tiny pilot study, which gathered data on only a dozen boys. Sarepta says that their investigators gathered clear evidence that their drug helped boys with this crippling, devastating disease continue to walk further distances than historical data would consider possible without a therapeutic effect. FDA insiders like Farkas, though, rejected the historical comparisons and criticized the biotech for failing to pursue a larger study earlier.

The approval comes after several potential rivals have been slapped down, with BioMarin’s candidate rejected — and now shelved — and PTC’s drug refused a hearing after insiders at the agency concluded that the company simply had not made its case.

Those earlier refusals leave Sarepta with a clear shot at its market.

Janet Woodcock, the FDA’s Center for Drug Evaluation and Research director, said:

“Patients with a particular type of Duchenne muscular dystrophy will now have access to an approved treatment for this rare and devastating disease. In rare diseases, new drug development is especially challenging due to the small numbers of people affected by each disease and the lack of medical understanding of many disorders. Accelerated approval makes this drug available to patients based on initial data, but we eagerly await learning more about the efficacy of this drug through a confirmatory clinical trial that the company must conduct after approval.”


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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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