Sarepta to lay off 500 employees and add black box warning for gene therapy.

Sarepta Therapeutics announced on Wednesday that the company will be laying off 500 employees and adding a severe warning to the label of its muscle disorder gene therapy Elevidys, following the recent deaths of two patients who were taking the drug. The U.S. Food and Drug Administration has requested that Sarepta add the most serious warning, a "black box" warning, stating that patients with Duchenne muscular dystrophy who are able to walk may experience acute liver injury and liver failure. Sarepta's stock price surged 33% in after-hours trading, as the company also announced that its restructuring efforts will reduce annual costs by around $400 million by 2026.