In a press release dated 30 October 2023, Sarepta Therapeutics announced the initial efficacy results of the Embark trial, a phase III trial of Elevydis (SRP-9001), a microdystrophin gene therapy drug approved in the United States in June 2023.
- The trial involved 124 participants aged between 4 and 7 years (59 aged between 4 and 5 years and 65 aged between 6 and 7 years).
- The results show that, one year after treatment, the overall functional score (NSAA scale) was better for the treated group (2.6) than for the placebo group (1.6), but the difference was not significant.
- Children treated with SRP-9001 got up from the ground slightly faster than those on placebo (-0.64 seconds) and were faster to walk 10 metres (-0.42 seconds), both significant differences.
Other safety and efficacy results for SRP-9001
The results of 3 other trials conducted over the last 5 years have recently been published: the Endeavor trial (phase I, still ongoing), an open-label phase I/II trial, and a double-blind, placebo-controlled phase II trial.
- All three trials agree that SRP-9001 is well tolerated: although there are many adverse effects in the 3 months following injection of the product, they remain moderate and transient (vomiting, loss of appetite, constipation, etc.).
- Similarly, significant production of dystrophin was found in the muscles of treated patients taken 3 months after treatment, whatever the trial.
- One year (Endeavor trial) and four years (phase I/II trial) after the administration of SRP-9001, the functional performance of treated patients was superior to that of a cohort of untreated, external patients (CIRNG cohort).
- On the other hand, in the phase II trial, although the functional performance of patients who had received treatment was better one year later than that of those who had received placebo, this difference was not significant, corroborating the data from the Embark trial.
Longer-term results are awaited to confirm or refute the efficacy of the product.
Sarepta Therapeutics Announces Topline Results from EMBARK, a Global Pivotal Study of ELEVIDYS Gene Therapy for Duchenne Muscular Dystrophy. Sarepta Therapeutics. Communiqué de presse du 30 Octobre 2023
Expression of SRP-9001 dystrophin and stabilization of motor function up to 2 years post-treatment with delandistrogene moxeparvovec gene therapy in individuals with Duchenne muscular dystrophy. Mendell JR, Shieh PB, McDonald CM et al. Front Cell Dev Biol. 2023 Jul 11
Delandistrogene Moxeparvovec Gene Therapy in Ambulatory Patients (Aged ≥4 to <8 Years) with Duchenne Muscular Dystrophy: 1-Year Interim Results from Study SRP-9001-103 (ENDEAVOR). Zaidman CM, Proud CM, McDonald CM. et al. Ann Neurol. 2023 Nov.
Long-term safety and functional outcomes of delandistrogene moxeparvovec gene therapy in patients with Duchenne muscular dystrophy: A phase 1/2a nonrandomized trial. Mendell JR, Sahenk Z, Lehman KJ. et al. Muscle Nerve. 2023 Aug 14.
