SHERIDAN, WYOMING – July 29, 2025 – Sarepta Therapeutics is once again under regulatory spotlight following the death of an 8-year-old boy in Brazil who had received its gene therapy Elevidys, triggering an FDA investigation and fresh market turbulence for the embattled biotech.
While Brazilian authorities and partner company Roche have attributed the fatality to severe influenza A infection compounded by immunosuppression, the FDA has launched a formal probe. The death, though deemed “unrelated to treatment with Elevidys” by the reporting physician, adds to growing concerns around the safety profile of Sarepta’s adeno-associated virus (AAV)-based gene therapy platform.
Regulators Reassess Risk Amid Fatality and Flu Season Timing
According to Sarepta’s own statement, the boy’s death occurred on June 7 and was reported to the FDA through its postmarketing surveillance system on June 18. The FDA confirmed receipt but only announced its investigation weeks later. This delay, along with the FDA’s decision to probe a death considered unrelated by local health authorities, has raised eyebrows among biotech analysts.
Brazil’s National Health Surveillance Agency responded by suspending the import, manufacture, marketing, and distribution of Elevidys throughout the country as a precaution. The move echoes prior regulatory actions taken in the U.S., where Sarepta agreed to halt domestic shipments of the therapy following multiple adverse events.
Use of Elevidys in Off-Label Context Sparks Ethical Questions
The deceased boy was not enrolled in a clinical trial and did not meet Elevidys' approved indication range, which in Brazil includes only ambulatory boys aged 4 to 7 years old. Analysts from William Blair noted, “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.’”
This off-label use—likely rushed due to age cutoffs—highlights a tension between compassionate access and clinical protocol, especially for progressive conditions like Duchenne muscular dystrophy (DMD) where therapeutic windows are narrow.
Mounting Concerns Over AAV Gene Therapy Safety
Sarepta’s gene therapy platform has faced escalating scrutiny since March, when the company disclosed a death due to acute liver failure—a recognized risk associated with AAV vectors. A second Elevidys-related death followed in June. Earlier this month, a third fatality was linked to SRP-9004, an experimental AAV therapy targeting limb-girdle muscular dystrophy.
Although AAV vectors offer targeted delivery and long-term expression of therapeutic genes, they also carry immune and hepatic risks. Immunosuppressive regimens used to manage these responses can further increase patient vulnerability, particularly during periods of high viral circulation.
Stakeholder Doubts Surround Investigation Timing
Despite the absence of direct causality in the Brazilian case, the FDA’s delayed but active investigation has raised questions. In their Monday note, William Blair analysts remarked, “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.”
This inconsistency has amplified frustration within the investor community and underscored the urgent need for harmonized global regulatory oversight of emerging genetic treatments.
Strategic Implications for Sarepta and Global Gene Therapy Rollouts
The Brazilian death, though not conclusively linked to Elevidys, may intensify pressure on developers to refine eligibility, enhance pharmacovigilance, and develop safer delivery platforms. Hospitals and providers are also likely to reevaluate protocols for immunosuppressive regimens during gene therapy administration, particularly during peak infection seasons.
Sarepta’s market position has been severely weakened, with shares falling 7% on Friday and broader confidence in its AAV pipeline continuing to erode. As regulatory reviews expand and public scrutiny intensifies, the biotech faces a critical inflection point in determining whether its platform can regain trust across global markets.
Learn more about Sarepta’s clinical programs and regulatory updates at www.sarepta.com