MDA 2026: Sevasemten halts functional decline in Becker trial
Patients' motor function stable over several years, data show
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Becker muscular dystrophy (BMD) patients who received the experimental treatment sevasemten in clinical trials had stable motor function over several years of follow-up, new data showed.
That stands in contrast to the typical progression of BMD, in which motor function steadily declines as the disease progresses.
The data were presented at the Muscular Dystrophy Association (MDA)Clinical & Scientific Conference 2026, held March 8-11 in Orlando, Florida, and online. Analyses presented at the conference also indicated that sevasemten can help maintain or improve heart health in BMD patients. The studies were funded by sevasemten’s developer, Edgewise Therapeutics.
BMD is caused by mutations that lead to reduced activity of dystrophin, a muscle protein that normally acts as a shock absorber to help cushion muscle cells against damage. Low dystrophin activity in BMD leads muscle cells to accumulate wear-and-tear damage over time, ultimately leading to symptoms such as progressive muscle weakness. This can affect the muscles that move the body, as well as the heart muscles.
Sevasemten is a daily oral therapy designed to inhibit myosin, a protein that plays a key role in muscle contraction. By reducing myosin activity, the therapy aims to make muscle contractions gentler, so that muscles don’t accumulate as much damage over time.
Clinical trials show promise
Edgewise has conducted several clinical trials to evaluate sevasemten as a potential treatment for BMD. In an early Phase 1 study called ARCH (NCT05160415), a dozen patients received the therapy, and motor scores indicated stabilization out to two years.
A Phase 2 trial called CANYON (NCT05291091) then tested sevasemten against a placebo in 40 adults and 29 adolescents with BMD.
The CANYON study met its main goal, with sevasemten outperforming the placebo at reducing markers of muscle damage after one year. At the conference, a team led by Edgewise scientists presented a poster with new analyses from CANYON looking at available data on heart health.
The researchers looked at left ventricular ejection fraction (LVEF) — a measure of how efficiently the heart pumps oxygen-rich blood to the body — and blood levels of NT-proBNP, a marker of heart muscle damage. The poster, titled “Effects of Sevasemten on LVEF and NT-proBNP in Adults with Becker muscular dystrophy in CANYON,” covered data from 28 adults who were given sevasemten and 12 who were given the placebo.
Results showed that NT-proBNP levels were unchanged over a year in patients given sevasemten. NT-proBNP levels tended to be lower in patients given sevasemten than in those given a placebo, but the difference wasn’t statistically significant, suggesting a non-negligible chance that it was random.
Among patients whose LVEF was within normal range at the start of the study, LVEF remained largely unchanged in those given sevasemten, whereas it tended to worsen in those given the placebo. And among patients with below-normal LVEF at the study’s start, LVEF tended to improve in those given sevasemten, while it remained low in those given the placebo. In both cases, the difference between sevasemten and placebo was statistically significant, meaning it’s highly unlikely these differences can be explained by random chance.
“LVEF was maintained or trended towards improvement during twelve months of sevasemten treatment, while NT-proBNP was stable and trended lower than placebo,” the researchers concluded. “These results support the cardiovascular safety profile of sevasemten and may indicate a potentially cardioprotective [heart-protective] role for sevasemten in adults in BMD.”
Extension study results point to continued benefits
Patients who completed CANYON or the earlier ARCH trial had the option to continue in an ongoing extension study called MESA (NCT06066580), in which all participants are being treated with sevasemten and monitored for long-term outcomes. A separate poster at the MDA conference, “Long-term stabilization of function in Becker: Sevasemten prevented functional decline up to 3.5 years in MESA open-label extension,” reported findings from a subset of participants who have been followed for at least a year in the extension study.
The analysis looked at how sevasemten affected scores on the North Star Ambulatory Assessment (NSAA), a standardized measure of motor function. In people with untreated BMD, NSAA scores usually decrease (worsen) by at least one point per year as the disease progresses.
In patients who’d been on sevasemten in CANYON, the average NSAA score increased (improved) by 0.2 points in the original year-long study, and after another year on sevasemten in MESA, average NSAA scores were 0.1 points higher than they’d been prior to starting sevasemten. In patients given the placebo in CANYON who started sevasemten in the extension study, NSAA scores increased by 0.2 points after a year on the therapy.
And in 11 patients who’d started on sevasemten in the earlier ARCH study, average NSAA scores were 0.1 points higher than they’d been before treatment after 3.5 years on sevasemten. No new safety issues were reported in the long-term study.
“In participants with up to 3.5 years of sevasemten exposure, NSAA scores were stabilized with a favorable safety profile,” the researchers concluded.
Edgewise is now running GRAND CANYON, an expansion of the CANYON study. That trial is testing sevasemten against a placebo in a larger group of BMD patients, with the main goal of assessing the impact on NSAA scores after 1.5 years. Assuming the results are positive, Edgewise hopes to use data from GRAND CANYON as a basis for applying for approval of sevasemten.
Note: The Muscular Dystrophy News Today team is providing live coverage of the 2026 MDA Clinical & Scientific Conference March 8-11 in Orlando, Florida. Go here to see the latest stories from the conference.
