Sarepta Provides Safety Update for ELEVIDYS and Initiates Steps to Strengthen Safety in Non-Ambulatory Individuals with Duchenne

Sarepta Therapeutics, Inc. (NASDAQ:SRPT), the leader in precision genetic medicine for rare diseases, today provided a safety update regarding ELEVIDYS (delandistrogene moxeparvovec-rokl), the only approved gene therapy for patients with Duchenne muscular dystrophy, and steps the Company is taking to strengthen the safety profile in non-ambulatory patients. These steps follow a second reported case of acute liver failure (ALF) resulting in death. The cases of ALF to date have both occurred in non-ambulatory individuals with Duchenne. Sarepta extends its deepest sympathies to the affected families and care teams.

Key Safety Initiatives

Evaluating and Enhancing Immunosuppressive Regimen: As part of a comprehensive review of safety data, Sarepta is taking proactive steps to mitigate the risk of acute liver failure in non-ambulatory patients. Sarepta is working to immediately convene an independent group of leading experts in Duchenne and liver health to consider an enhanced immunosuppression regimen for ELEVIDYS. This panel will evaluate data and assess our proposed regimen, which includes sirolimus and is supported by preclinical data demonstrating the effectiveness of additional immunosuppression in moderating liver enzyme elevations, a key factor in mitigating potential safety events. Sarepta will share the panel's recommendations with the U.S. Food & Drug Administration (FDA), and implementation of any new regimen will be subject to FDA guidance and allowance.

Suspending Shipments of ELEVIDYS for Non-Ambulatory Patients: Sarepta is temporarily suspending shipments of ELEVIDYS for non-ambulatory patients while an enhanced immunosuppressive regimen is evaluated, discussed with regulatory bodies, and put in place.

For ambulatory patients, no treatment changes are being proposed and the current practice of administering corticosteroids before and after ELEVIDYS infusion, along with post-treatment monitoring, remains the same.

ENVISION Study Paused: Sarepta has voluntarily paused dosing in the ENVISION clinical study (also known as Study SRP-9001-303). FDA concurs with this action. The pause will allow for the evaluation of a protocol amendment to incorporate an enhanced immunosuppressive regimen for the non-ambulatory patient cohort and incorporate any additional feedback from the FDA. Regulatory alignment is needed before screening and dosing in ENVISION may resume.