Patient dies following muscular dystrophy gene therapy, Sarepta reports microbiologystudy

Sarepta Therapeutics said Tuesday that a patient died while taking its closely watched gene therapy for muscular dystrophy, sending company shares plummeting in morning trading.

The young man died of acute liver injury, a known side effect, Sarepta said in a statement. But the company said the “severity” of the patient’s case had not previously been seen with the therapy, called Elevidys. It’s the first known patient death with the therapy, which has been used in more than 800 patients, the company said.

In 2023, Elevidys received expedited U.S. approval despite concerns from some Food and Drug Administration scientists about its effectiveness in treating Duchenne muscular dystrophy. It’s the first gene therapy approved in the U.S. for the rare muscle-wasting condition, which causes weakness, loss of mobility and early death in males.

The FDA granted full approval last year for Duchenne’s patients with a particular genetic mutation, expanding its use to patients 4 and older, regardless of whether they are still able to walk. Previously it was only available for younger patients who were still mobile.

Sarepta said in a statement the patient who died had a recent infection that could have contributed to the liver injury. The company said it plans to update the prescribing information for Elevidys to reflect the case.

Shares of the Cambridge, Massachusetts-based company fell more than 23% to about $78 per share in morning trading.

Elevidys uses a disabled virus to insert a replacement gene for producing dystrophin into patient cells. It costs $3.2 million for a one-time treatment.

Sarepta has received FDA accelerated approval for three other Duchenne’s drugs since 2016. None has yet been confirmed to work; studies designed to secure full FDA approval are ongoing.

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