Sarepta Therapeutics lays off 493 workers amid FDA probe, stock drop, and concerns over its gene therapy treatment, Elevidys.

Shares of Sarepta Therapeutics plunged more than 30% on Friday as the future of its approved gene therapy appeared at risk. Sarepta has reported three patient deaths related to its gene therapies.

Sarepta Therapeutics, Inc. (NASDAQ:SRPT), the leader in precision genetic medicine for rare diseases, today issued the following statement:

As mothers of children with this disease, we have wept helplessly in recent months as friends — fellow members of a club we never asked to join — said goodbye to their sons, the babies they once held in their arms, whose dreams they held in their hearts until Duchenne robbed them of working muscles or a healthy future.

The drop comes the day after the drugmaker said it would add a so-called black-box warning to its gene therapy Elevidys after two teenage boys receiving the treatment died earlier this year.

The restructuring enacted by Sarepta Therapeutics is expected to save up to $400 million in annual costs. Read why I'm downgrading SRPT stock from Hold to Sell.

A company spokesperson told Bloomberg that a 51-year-old patient died of acute liver failure last month in an early-stage trial of a gene therapy to treat limb-girdle muscular dystrophy.