Shares of Sarepta Therapeutics plunged more than 30% on Friday as the future of its approved gene therapy appeared at risk. Sarepta has reported three patient deaths related to its gene therapies.

The Food and Drug Administration plans to ask Sarepta Therapeutics Inc. to pause shipments of its Elevidys treatment after three deaths were linked to the company’s gene therapies, according to a person familiar with the matter.

The agency's scrutiny of Sarepta has sharpened since the deaths of two teenage boys earlier this year who had received Elevidys, a gene therapy approved in the United States to treat a muscle-wasting condition called Duchenne muscular dystrophy.