Sarepta Reports Teen Death After Gene Therapy Treatment

(Reuters) -Sarepta Therapeutics said on Tuesday a 16-year-old boy has died due to acute liver failure, months after he received the company’s U.S-approved gene therapy for a rare muscular dystrophy.

The patient underwent treatment in December with Sarepta’s Elevidys, the company told Reuters in an emailed statement. Elevidys is the only FDA-approved gene therapy for Duchenne muscular dystrophy patients aged four and above.

Duchenne muscular dystrophy affects an estimated one-in-3,500 male births worldwide, according to the National Organization for Rare Disorders. It weakens skeletal and heart muscles, which quickly get worse with time, and patients often die by the time they are 25.

Sarepta’s shares declined nearly 24% to $77.09 in early trading following the news of death of a patient.

Although, acute liver injury is a known possible side effect of the therapy – also mentioned in its prescribing information – a death due to liver failure represents a previously unreported severity, the company said.

Sarepta said the death has been reported to relevant health authorities and doctors. It also plans to update the therapy’s prescribing information to “appropriately represent” the adverse event.

RBC Capital Markets analyst Brian Abrahams said the death could make doctors more hesitant about using Elevidys in patients, especially since its clinical benefits are considered “relatively modest.”

Elevidys, which failed to meet the main goals of a late-stage trial, has previously been dogged by regulatory delays and questions about its effectiveness.

Sarepta said testing showed the patient also had a recent infection, called cytomegalovirus, which can affect the liver, and that it was identified by a treating physician as a possible contributing factor.

(Reporting by Sriparna Roy and Bhanvi Satija in Bengaluru; Editing by Shilpi Majumdar and Shinjini Ganguli)