Second patient death reported with gene therapy for muscular dystrophy

Sarepta Therapeutics' shares plummeted over 42% after a second patient death was reported in connection with its Duchenne's muscular dystrophy gene therapy, Elevidys, leading to a pause in shipments for older, non-ambulatory patients. The death, like a previous one, involved acute liver injury in a teenage boy, prompting Sarepta to assemble an expert panel to recommend revised safety protocols, potentially including increased immunosuppressant use. Analysts speculate the FDA, under new leadership, might impose further restrictions or block Elevidys' use in non-ambulatory patients, despite its $3.2 million price tag and prior expedited approval.

Analysis

Sarepta Therapeutics (SRPT) experienced a significant share price decline of over 42%, closing at approximately $21, following the announcement of a second patient death linked to its gene therapy, Elevidys. This $3.2 million treatment for Duchenne's muscular dystrophy has now seen two fatalities, both teenage boys suffering acute liver injury, a known side effect attributed to the immune system's response and notably occurring in older patients receiving larger doses. In response, Sarepta has paused shipments and a clinical study of Elevidys for older, non-ambulatory patients and is establishing an expert panel to propose revised safety protocols, potentially involving increased use of immunosuppressants, which will require FDA approval. Elevidys, which secured accelerated approval in 2023 and subsequently full approval with expanded use last year despite initial concerns from some FDA scientists, now faces heightened regulatory scrutiny. Market analysts, including Leerink Partners' Joseph Schwartz, indicate an increased probability that the FDA, potentially influenced by new leadership such as Dr. Vinay Prasad who has been critical of the therapy, could impose more stringent restrictions or even withdraw Elevidys for non-ambulatory patients, thereby significantly impacting its commercial viability.

Key Decisions for Investors

• Investors should closely monitor Sarepta's communications with the FDA and the forthcoming recommendations from the expert panel regarding Elevidys' revised safety protocols, as these will be critical determinants for the therapy's continued market access, especially within the non-ambulatory patient segment.
• The severe adverse events, substantial stock depreciation, and extremely negative sentiment (-0.95 for SRPT) necessitate a thorough reassessment of Sarepta's risk profile and the future revenue projections for Elevidys, its pivotal $3.2 million gene therapy.
• Given the significant regulatory overhang and the explicit concerns about potential FDA actions, including stricter usage limitations or market withdrawal for certain patient cohorts, a cautious stance is warranted, as such outcomes could drastically alter Sarepta's commercial outlook.