Sevasemten Misses Primary Endpoint in Pivotal Trial for Becker Muscular Dystrophy

According to a recent news update from Servier, the company’s investigational agent sevasemten failed to meet its primary or secondary endpoints in the pivotal GRAND CANYON trial for Becker muscular dystrophy (BMD). The result reverses years of positive signals for a therapy that had been positioned to become the first approved treatment for the disease, which currently has none.¹

GRAND CANYON is the pivotal cohort of a broader clinical program (NCT05291091) that also includes the phase 2 CANYON study. It randomized about 120 adults with BMD 2:1 to oral sevasemten or placebo over 18 months, with change in the North Star Ambulatory Assessment (NSAA) as the primary endpoint. Servier said sevasemten showed no statistically significant benefit on the NSAA and that unspecified secondary endpoints also were not met.

The company reported a continued favorable safety and tolerability profile and said it is conducting a comprehensive analysis of the GRAND CANYON dataset alongside prior clinical data, noting that the results are not aligned with findings from earlier studies, including CANYON. Full results are expected to be presented at a later date.

The miss stands in contrast to CANYON, the placebo-controlled phase 2 trial that preceded GRAND CANYON and met its primary endpoint in December 2024. Craig M. McDonald, MD, distinguished professor and chair of physical medicine and rehabilitation at UC Davis Health and CANYON's principal investigator, said at the time that BMD “has no approved therapies” and that he looked forward to the pivotal GRAND CANYON results.²

Servier acquired the Becker and Duchenne muscular dystrophy program, including sevasemten, from Edgewise Therapeutics in June 2026 for up to $2.65 billion, consisting of a $1.55 billion upfront payment and up to $1.1 billion in regulatory and commercial milestones. Edgewise said the sale let it concentrate on its cardiovascular pipeline.³

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In two-year data from the single-center, open-label ARCH trial reported in April 2024, NSAA scores in 12 adult men with BMD changed by a mean of -0.2 points over 24 months of daily sevasemten, compared with a natural history average decline of -2.4 points. Creatine kinase and fast skeletal muscle troponin I levels fell and were sustained, and the therapy was reported as well tolerated, with no serious adverse events, dose reductions, or discontinuations due to adverse events among the 12 participants.⁴

The CANYON data behind that primary-endpoint win, detailed in December 2024, showed sevasemten produced a 28% greater average reduction in creatine kinase than placebo over months 6 through 12 in 69 adults and adolescents with BMD (P =.02). A 1.1-point advantage on the NSAA in adults did not reach statistical significance (P =.16), and Edgewise noted that adult sevasemten-treated patients had more advanced disease at baseline than the placebo group. Fast skeletal muscle troponin I fell 77% more than placebo from months 3 to 6 (P <.001).²

In June 2025, the FDA told Edgewise that the CANYON data alone were insufficient to support accelerated approval, while affirming that the NSAA could serve as a clinically meaningful endpoint for traditional approval and voicing support for GRAND CANYON as a single, adequate, well-controlled study to support registration.⁵

The same day, Edgewise reported extension data from MESA, an open-label study: CANYON participants who continued into MESA gained 0.8 NSAA points over 18 months, placebo patients who switched to sevasemten improved 0.2 points, and ARCH participants remained stable after 3 years. Joanne Donovan, PhD, MD, then Edgewise's chief medical officer, said the company was “well positioned to deliver the first ever therapy for individuals with Becker muscular dystrophy.”⁵

A cardiac biomarker analysis presented at the 2026 Muscular Dystrophy Association Clinical & Scientific Conference, held March 8-11, 2026, in Orlando, Florida, reported exploratory findings from CANYON suggesting a potential cardioprotective effect: left ventricular ejection fraction remained stable or trended toward improvement on sevasemten, and N-terminal pro-B-type natriuretic peptide trended lower than with placebo. The analysis, based on fewer than 40 participants, was described as hypothesis-generating.⁶

REFERENCES
1. Topline pivotal results of sevasemten in Becker muscular dystrophy. News release. Servier. Published November 3, 2026. Accessed November 5, 2026. https://servier.com/en/newsroom/topline-pivotal-results-sevasemten-becker/
2. Edgewise Therapeutics announces positive topline results from the CANYON phase 2 trial of sevasemten in individuals with Becker muscular dystrophy (Becker). News release. Edgewise Therapeutics. Published December 16, 2024. Accessed November 5, 2026. https://www.businesswire.com/news/home/20241216264915/en/Edgewise-Therapeutics-Announces-Positive-Topline-Results-from-the-CANYON-Phase-2-Trial-of-Sevasemten-in-Individuals-with-Becker-Muscular-Dystrophy-Becker
3. Servier to acquire Edgewise Therapeutics' muscular dystrophy business. News release. Servier. Published June 1, 2026. Accessed November 5, 2026. https://servier.com/en/newsroom/acquisition-edgewise-therapeutics-muscular-dystrophy-business/
4. Edgewise Therapeutics announces positive two-year topline results from the ARCH open label trial of sevasemten (EDG-5506) in adults with Becker muscular dystrophy (Becker). News release. Edgewise Therapeutics. Published April 15, 2024. Accessed November 5, 2026. https://www.businesswire.com/news/home/20240415221564/en/Edgewise-Therapeutics-Announces-Positive-Two-Year-Topline-Results-from-the-ARCH-Open-Label-Trial-of-Sevasemten-EDG-5506-in-Adults-with-Becker-Muscular-Dystrophy-Becker
5. Edgewise Therapeutics reports positive results on sevasemten program for Becker and Duchenne muscular dystrophies. News release. Edgewise Therapeutics. Published June 26, 2025. Accessed November 5, 2026. https://www.prnewswire.com/news-releases/edgewise-therapeutics-reports-positive-results-on-sevasemten-program-for-becker-and-duchenne-muscular-dystrophies-302491562.html
6. Barthel B, Tran L, McDonald C, et al. Effects of sevasemten on LVEF and NT-proBNP in adults with Becker muscular dystrophy in CANYON. Presented at: 2026 Muscular Dystrophy Association Clinical & Scientific Conference; March 8-11, 2026; Orlando, FL. Abstract 470LB.