The U.S. Food and Drug Administration ( FDA) has placed an immediate clinical hold on Sarepta Therapeutics' investigational gene therapy trials for limb girdle muscular dystrophy following three patient deaths potentially linked to the company's treatments.

The head of the US Food and Drug Administration said the agency will “take a hard look” at a gene therapy from Sarepta Therapeutics Inc. after two patient deaths, adding pressure to the biotech company which also announced a third patient had recently died on a similar treatment.

The death of a third patient tied to a Sarepta Therapeutics gene therapy this year sent the company’s shares nosediving 36% Friday, halting the momentum the stock generated just a day earlier after announcing of a restructuring that entailed cutting about 500 jobs,