A second patient receiving its experimental gene therapy Elevidys has died from liver failure, raising serious questions on the drug’s outlook.

Sarepta Therapeutics shares sank to their lowest level in nine years Monday after a second patient taking its Elevidys drug died.

Shares of biotech company Sarepta Therapeutics (NASDAQ:SRPT) fell 44.4% in the afternoon session after the company reported a second death linked to its Duchenne muscular dystrophy gene therapy. Elevidys.