Sarepta Therapeutics failed to win the European drug regulator's backing for its muscle disorder gene therapy on Friday, as the company faces intense regulatory scrutiny after two recent patient deaths tied to the treatment.

The U.S. Food and Drug Administration (FDA) is investigating the death of an eight-year-old boy who received Sarepta Therapeutics (NASDAQ: SRPT) gene therapy, Elevidys, for Duchenne muscular dystrophy (DMD).

(Reuters) -The U.S. Food and Drug Administration said on Friday it was investigating the death of an eight-year-old boy who received Sarepta Therapeutics' muscular disorder gene therapy Elevidys. The death occurred on June 7, the agency said.