A patient has died while receiving Elevidys, a gene therapy for Duchenne muscular dystrophy, marking the first known death linked to the treatment. The company behind the drug, Sarepta Therapeutics, said that the patient suffered acute liver injury,

Shares of Sarepta Therapeutics SRPT plunged more than 20% yesterday after the company reported the death of a patient after treatment with Elevidys, its one-shot gene therapy for Duchenne muscular dystrophy (DMD).

Elevidys was approved after intense debate at the FDA, as officials and reviewers disagreed over how strong the evidence was and whether it warranted making the drug available for patients facing a fatal disease with few other options.

Sarepta Therapeutics said a patient taking its treatment for Duchenne muscular dystrophy has died from acute liver failure. The pharmaceutical firm said that "acute liver injury is a known possible side effect of Elevidys.