Brazilian authorities said the death was unlikely to have been caused by Elevidys and was instead more in line with severe infection exacerbated by immunosuppression.
The FDA is looking into the death of an 8-year-old boy in Brazil who had been treated with Sarepta Therapeutics’ Duchenne muscular dystrophy therapy Elevidys. The Massachusetts-based biotech has denied that the death is related to the gene therapy.
Roche, which owns the ex-U.S. rights to Elevidys and is in charge of shipping the therapy to Brazil, has clarified that the death is “unrelated to treatment with Elevidys,” citing the reporting physician, as per Sarepta’s news release on Friday. Both companies also noted that the boy wasn’t participating in any Elevidys clinical trials.
Additionally, Brazilian authorities noted that the death was unlikely to have been caused by Elevidys and instead is more likely a case of serious influenza A infection intensified by immunosuppression, as per an automated translation of a Portuguese-language release. Brazil’s National Health Surveillance Agency has suspended the marketing, distribution, manufacture and importation of Elevidys as a precautionary measure.
In its press release on Friday, Sarepta said it had reported this latest death to the FDA on June 18 through the agency’s postmarketing electronic database. The FDA, in its own release, noted that the death had occurred on June 7.
Sarepta’s already battered stock lost another 7% on Friday.
In an investor note early Monday morning, analysts at William Blair noted that “Elevidys is only approved for ambulatory boys ages 4-7 years old in Brazil.” The patient was 8 years old, and so he “may have been treated expeditiously before aging out of eligibility, and therefore treatment could not be delayed until after Brazil’s flu season,” they said.
“It is well understood that immunosuppression increases one’s risk for infections and infection-associated complications,” the analysts continued, nothing that the fatality points to the need for more research regarding the risks of such immunosuppressive regimens in the context of gene therapies.
William Blair also raised concerns with the timing of the probe and the need for an investigation in the first place. “We are puzzled as to why the FDA is investigating a death deemed unrelated to the gene therapy and why the investigation was initiated more than a month after it was submitted” to the regulator’s surveillance system.
Sarepta’s stock has been decimated in recent months as severe safety issues around Elevidys—and its gene therapy platform—surfaced. The biotech in March reported the first patient death associated with Elevidys, placing the blame on acute liver failure, a known complication of the AAV vectors that are used to deliver gene therapies. A second death followed in June.
Then, earlier this month, reports surfaced that a third patient had died after receiving a Sarepta gene therapy, though this fatality was linked to SRP-9004, which also uses an AAV vector, being trialed for limb-girdle muscular dystrophy.
In response to these deaths, the FDA asked Sarepta to suspend all U.S. deliveries of Elevidys, which the company agreed to do after initially resisting. Roche, which is in charge of Elevidys deliveries in Brazil, followed suit a few days later and suspended all shipments of the product to ambulatory patients outside the U.S that base their approvals on FDA decisions. The company had already halted shipments of Elevidys to non-ambulatory patients.
