Sarepta Therapeutics announced positive three-year results for Elevidys (delandistrogene moxeparvovec-rokl), the only approved gene therapy for Duchenne muscular dystrophy (DMD). The news provides a boost to Sarepta, after the US FDA last year temporarily blocked distribution of Elevidys following reports of acute liver failure and deaths in patients.

The Massachusetts-based firm posted topline data from Part 1 of EMBARK (Study SRP-9001-301), a global, randomized, placebo-controlled Phase III trial evaluating Elevidys in ambulatory individuals with DMD. The data showed that patients treated with Elevidys exhibited statistically significant, clinically meaningful, and durable benefits across key functional measures compared with a pre-specified propensity-weighted, untreated external control group.

At a mean age of about nine years, patients treated with Elevidys maintained North Star Ambulatory Assessment (NSAA) scores above baseline three years after treatment, while the external control group continued the expected age-related decline. The therapy demonstrated a 73% slowing of disease progression on Time to Rise (TTR) and a 70% slowing on 10-meter walk/run (10MWR) compared with controls, with the treatment effect widening between Year 2 and Year 3. No new treatment-related safety signals were observed, consistent with prior ambulatory patient experience. The data will be presented at upcoming medical meetings and in scientific publications.

Why it matters

DMD is a severe X-linked neuromuscular disorder caused by mutations in the dystrophin gene. Elevidys is a gene therapy that uses an adeno-associated virus (AAV) vector to deliver a functional micro-dystrophin gene to muscle cells, aiming to restore dystrophin protein expression and improve muscle function.

Sarepta picked up a first approval for the drug in 2023 and has continued to assess the molecule in multiple clinical trials with the aim of seeking expanded indications.

However, in June 2025, following documented cases of acute serious liver failure and injury post-Elevidys administration, including three deaths, the US FDA moved to place a clinical hold on the drug’s trials while Sarepta and commercial partner Roche voluntarily suspended distribution. That hold was lifted in July, as Sarepta revealed real-world data that showed deaths were linked solely to non-ambulatory DMD patients.

Following an update to the black box warning, the FDA issued an approval to changed prescribing guidelines in November, removing the non-ambulatory indication. Sarepta is also carrying out a clinical trial to assess an enhanced sirolimus immunosuppressive regimen to address the risk of acute liver failure/injury and potentially enable dosing to resume for non-ambulatory patients.