Sarepta Therapeutics (SRPT) stock fell sharply Tuesday after the company reported that the Food and Drug Administration issued a negative report on a drug the company is developing. The FDA said it considered Sarepta’s application for its experimental Duchenne muscular dystrophy drug, eteplirsen, to be “premature,” the company said Tuesday. Sarepta stock was down 62% in afternoon trading in the market Tuesday, at a 13-month low near 13.70.