Following three patient deaths linked to the drug—two in non-ambulatory patients due to liver injury and one in a limb-girdle muscular dystrophy trial—the FDA requested Sarepta to halt shipments in July, but this suspension was later lifted after regulatory discussions.

Despite the regulatory setbacks, Sarepta's market performance has been severely impacted, with its stock down 85% year-to-date, though demand for Elevidys persists.

In response to safety concerns, Sarepta has proposed new dosing guidelines that include the immunosuppressant sirolimus to reduce liver-related side effects, and 80% of surveyed doctors believe this will improve the safety profile.

However, doctors remain cautious; if a death occurs in ambulatory patients, roughly half would stop prescribing Elevidys and wait for further safety updates, although such an event has not yet happened.

Despite safety concerns and recent regulatory scrutiny, about 90% of surveyed doctors continue prescribing Sarepta's Elevidys for Duchenne muscular dystrophy, mainly for ambulatory patients, as no deaths have occurred in this group.

Since July 28, 27 patients have been infused with Elevidys, generating approximately $95 million in sales, even as Sarepta reported a 25% decline in sales in its second quarter earnings.

Elevidys is approved for ambulatory patients aged four and older with confirmed DMD mutations, and also for non-ambulatory patients under accelerated approval, which requires ongoing demonstration of benefit for full approval.

The drug's use has been linked to three patient deaths—two in non-ambulatory patients due to liver injury and one in a limb-girdle muscular dystrophy trial—raising safety concerns related to AAV vector gene therapies.