Sarepta’s Gene Therapy Shows Sustained Promise in DMD Treatment

New long-term data for Sarepta Therapeutics' gene therapy, ELEVIDYS, indicates a durable clinical benefit for ambulatory patients with Duchenne muscular dystrophy (DMD). The three-year results from the EMBARK study come at a pivotal moment, as the company's older therapeutic approaches have recently faced setbacks, positioning this treatment as a potential cornerstone of its future.

The latest analysis demonstrates that the therapy's effectiveness persists three years after administration. Patients treated with ELEVIDYS exhibited a 70% slower decline in motor function compared to an external control group. Key assessments, including time to stand and performance in a 10-meter walk test, showed this significant slowing of physical decline.

Notably, the functional advantage for treated patients over the control group widened considerably between the second and third year of follow-up. Furthermore, investigators reported no new safety signals during this extended observation period, confirming the treatment's stable safety profile. This stability is a crucial factor for the therapy's commercial pathway following previous regulatory actions.

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Regulatory Context and Future Expansion

The positive long-term data contrasts with recent developments for Sarepta's older exon-skipping drugs, Amondys 45 and Vyondys 53. The Phase 3 ESSENCE trial for those therapies failed to meet its primary endpoint, highlighting the shifting focus within the company's portfolio toward its gene therapy platform.

ELEVIDYS currently holds a narrowed FDA approval, restricted to ambulatory DMD patients only as of November 2025. This limitation was implemented due to serious liver injury cases observed in non-ambulatory patients, which also prompted a boxed warning on the product label. The central question now is whether combining the therapy with immunosuppressants can pave the way for a broader label.

Sarepta aims to address this by the end of 2026. The company plans to submit data from a combination study of ELEVIDYS and the immunosuppressant Rapamycin. These results are intended to support a regulatory application to extend the treatment's approval to non-ambulatory DMD patients, which would substantially increase the eligible patient population.