NEW YORK – Sarepta Therapeutics on Tuesday disclosed that a Duchenne muscular dystrophy patient died after receiving its gene therapy Elevidys (delandistrogene moxeparvovec).
Following the announcement, the Cambridge, Massachusetts-based biotech's stock price on the Nasdaq dropped around 27 percent to $73.54 on Tuesday at market close, from Monday's closing price of $101.35.
"We are profoundly saddened to share that a young man with Duchenne muscular dystrophy has passed away following treatment with Elevidys, having suffered acute liver failure," Sarepta said in a statement. "Acute liver injury is a known possible side effect of Elevidys and other [adeno-associated virus]-mediated gene therapies and is highlighted in the prescribing information."
Elevidys is the only gene therapy for Duchenne on the US market. It uses an adeno-associated virus vector to deliver a gene that encodes for microdystrophin, an engineered protein developed by Sarepta that it says can carry out the normal functions of dystrophin, the protein that is deficient or abnormal in Duchenne patients.
Sarepta noted in a statement that while acute liver failure is a known safety risk of Elevidys, the "benefit-risk of Elevidys remains positive" and it had not previously led to any patient deaths. More than 800 patients have received Elevidys through clinical trials or via physician prescription, according to Sarepta.
The patient who died also had a recent cytomegalovirus infection, which can damage the liver and which the treating physician identified as a possible contributing factor to his death, the firm noted. Sarepta said it will update Elevidys' prescribing information to "appropriately represent this event."
In an emailed statement, a Sarepta spokesperson maintained that Elevidys has a manageable and consistent safety profile and that the company is continuing to gather information on this event and work with the US Food and Drug Administration.
"It is our intention to update the prescribing information to appropriately represent this reported liver failure event and any additional monitoring requirements," the spokesperson said. "Ahead of any product label updates, we have informed healthcare providers and investigators who administer Elevidys about the event, along with leaders in the Duchenne patient advocacy community."
The FDA last year granted Elevidys traditional approval for ambulatory patients 4 years of age and older with a confirmed DMD mutation, as well as accelerated approval in non-ambulatory individuals in the same age range, despite concerns from some agency reviewers and a failed Phase III confirmatory trial.