The death of a boy with Duchenne muscular dystrophy, tied to a gene therapy, is above all a tragedy. But it is also undermining investor confidence in the company that makes it.

Another person treated with Elevidys suffered acute liver failure, leading Sarepta to discontinue treatment in certain patients while it evaluates new safety precautions.

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