Following a second patient death, Sarepta is temporarily suspending use of Elevidys in non-ambulatory DMD patients, pending evaluation of an enhanced immunosuppression regimen.

Sarepta Therapeutics stock plummeted Monday after the company said a second patient receiving its gene therapy died from liver failure, raising serious questions on the drug’s outlook.Shares fell 40% to $21.

Shares in both companies were down following news of the second death, casting fresh safety concerns over Elevidys.