November 5, 2026

 

Update for the Duchenne Community: ELEVIDYS Research, ENVISION and Our Exon-Skipping Programs

Dear Duchenne Community,

We know how closely individuals and families living with Duchenne follow developments in research and treatment.  We recognize the responsibility we have to share information clearly, transparently, and with compassion, including what we are learning, what decisions we are making, and what remains ahead.

Today, we want to share several important updates from Sarepta, including new data on ELEVIDYS, an important decision regarding the ENVISION clinical trial, continued plans to explore treatment approaches for non-ambulatory individuals, and progress across our exon-skipping programs. This is quite a long letter so please let us know if you have questions!

Continuing to build our understanding of ELEVIDYS

As more individuals receive ELEVIDYS and we gain additional years of experience following treatment, we continue to build our understanding of its effects over time. Recent presentations at the 2026 Annual Neuromuscular Study Group Scientific Meeting and the World Muscle Society Annual Congress included new findings that add to this growing body of evidence.

Two-year data in ambulatory individuals treated at ages 8–12: We shared additional results showing that older ambulatory individuals treated with ELEVIDYS continued to demonstrate benefit across multiple measures of motor function at two years, including the North Star Ambulatory Assessment (NSAA) and timed function tests, relative to a well matched group of individuals. These results were compared with those of a well-matched group of individuals who had not received ELEVIDYS. The findings contribute to our understanding of the durability of treatment effects and functional outcomes over time in this population.

Early findings in children ages 2–3: We also presented data from children who received ELEVIDYS at ages 2 and 3 years. Twelve weeks after treatment, testing showed the presence of ELEVIDYS-produced dystrophin in muscle tissue, including evidence that the protein was located at the muscle cell membrane. These findings provide an early indication of the treatment's biological activity. However, understanding how these early findings translate into longer-term clinical outcomes will require continued follow-up over time.

Real-world safety monitoring: At the Annual Neuromuscular Study Group Scientific Meeting, we also shared initial findings from the ELEVIDYS Phase 4 ENDURE study, which is evaluating approaches to managing and monitoring liver safety in real-world clinical practice. These early findings were consistent with the established safety profile observed in previous clinical trials, with no new safety signals identified. ENDURE is a longer-term study with plans to recruit approximately 500 participants ages 4 and older. Continued participation and follow-up will help us learn more about treatment administration, safety monitoring, and the experience of individuals receiving gene therapy in clinical practice.

An important update on the ENVISION clinical trial

We know that many families have been following the global Phase 3 ENVISION study, which was designed to evaluate ELEVIDYS in non-ambulatory and late-ambulatory individuals.

The study enrolled 90 participants across 14 countries, including 64 non-ambulatory and 26 late-ambulatory individuals. As many of you know, ENVISION has been on global clinical hold since 2025. This means that the study has been paused for over a year. At the same time, we continue to evaluate approaches to help manage potential safety risks in non-ambulatory individuals, including an immunosuppressive regimen with sirolimus being studied in Cohort 8 of the ongoing ENDEAVOR trial.

After careful consideration, we have made the decision to close enrollment in ENVISION and proceed with analysis of the blinded data from Part 1 of the study. This means the study will not be reopened to new participants.

Why are we making this decision?

We understand that families may wonder why the study cannot simply resume once additional safety information becomes available.

Because ENVISION has been on hold for an extended period, any potential restart of the study would require a change to the original study design. Specifically, if supported by findings from ENDEAVOR Cohort 8, non-ambulatory participants would need to receive blinded sirolimus in addition to corticosteroids before treatment. This would mean combining data from individuals who received different treatment approaches, making it difficult to interpret the results within the original study design.

We carefully considered whether continuing ENVISION under a modified design would provide meaningful and reliable information.  We believe the best path forward is to close enrollment and proceed with analysis of the data already collected. This enables us to report data to the community in a more timely manner.

We recognize how much individuals and families contribute when they participate in clinical research. Their time, commitment, and willingness to help advance science are invaluable. We are committed to respecting the contributions of every participant and supporting families through the next steps.

What happens next for ENVISION participants?

Clinical trial sites are working directly with participants and families to discuss individual next steps and transition plans. If you or a family member is participating in ENVISION, please contact your study investigator or clinical trial team with questions about your participation and follow-up.

Once the study database is closed, information about individual treatment assignments will be provided to participants from their study doctors.

Depending on their previous study treatment and the applicable safety and regulatory decisions:

  • Individuals who received ELEVIDYS will be invited to transition into the EXPEDITION long-term follow-up study (Study 305; NCT05967351).
  • Individuals who received placebo may have the opportunity to receive ELEVIDYS through an open-label crossover. This possibility depends on a number of factors, including the safety findings from ENDEAVOR Cohort 8, as well as Data Monitoring Committee and regulatory review and authorization to lift the clinical hold.

Your study team will be able to provide information about what these plans mean for you or your family member as well as timelines for next steps.

Continuing to explore a path forward for non-ambulatory individuals

We remain committed to researching a potential development path for non-ambulatory individuals living with Duchenne.

We continue to enroll non-ambulatory individuals in Cohort 8 of the ENDEAVOR study, which is evaluating a preventative immunosuppressive approach using oral sirolimus alongside corticosteroids. The findings will help inform our understanding of the safety of ELEVIDYS in this population and support discussions with the FDA about potential next steps.

We anticipate meeting with the FDA in early 2027 to discuss the available information from this study, and a potential path for non-ambulatory individuals in the US.

More information about ENDEAVOR is available at ClinicalTrials.gov – NCT04626674.

You can also contact us at [email protected].

Updates on our exon-skipping programs

In addition to our gene therapy research, we continue to build more evidence for our three exon-skipping programs for Duchenne.

In the U.S., FDA’s target action date for the supplemental New Drug Applications (sNDAs) for AMONDYS 45 (casimersen) and VYONDYS 53 (golodirsen) is expected at the end of February 2027. These applications request conversion from accelerated approval to traditional approval.

This represents an important next step in the regulatory review process for these therapies. We will share additional information as it becomes available.

We have also completed the MIS51ON study, designed to evaluate the safety and tolerability of two doses of EXONDYS 51 (eteplirsen). This study is completed and data are being analyzed now. This is an important part of our ongoing work to advance our understanding of Duchenne and the potential role of exon-skipping therapies. We are extremely grateful for the individuals and families whose participation made this research possible.

Our continued commitment to the Duchenne community

We recognize that these updates are more than clinical trial milestones or scientific findings. Behind every study, data presentation, and regulatory decision are individuals and families navigating the realities of Duchenne, making difficult decisions, and hoping for more time, greater independence, and better outcomes.

We do not take your trust for granted. We are committed to sharing what we know, being honest about what we are still learning, and listening to the experiences and perspectives of individuals and families living with Duchenne. Your insights and experiences are essential to helping inform our research and decisions.

To everyone who has participated in a clinical trial, shared your experiences, advocated for the community, or supported a loved one through this journey: thank you. We are deeply grateful for your partnership and remain committed to partnering with you.

If you have questions, please reach out to us at [email protected].

Sincerely,

 

Wendy Erler
SVP Patient Affairs