ClinicalTrials.gov posted results on 20 August 2026 from a completed Phase 3 study of mavacamten in symptomatic non-obstructive hypertrophic cardiomyopathy. The trial enrolled 580 participants and compared mavacamten with placebo. At week 48, Treatment 1 showed greater average improvement than Treatment 2 on several symptom and health-status measures, while the reported confidence intervals for some between-group analyses crossed zero.

Background

The study evaluated mavacamten for safety, tolerability, and efficacy in participants with symptomatic non-obstructive hypertrophic cardiomyopathy. The registry describes the comparison as mavacamten versus placebo. The supplied data do not provide additional information about the drug’s mechanism, dosing, prior approvals, or disease prevalence.

Trial design

This was a completed Phase 3 study in people with hypertrophic cardiomyopathy. The registered condition was non-obstructive hypertrophic cardiomyopathy, and the study intervention was mavacamten. Participants were evaluated against placebo for safety, tolerability, and efficacy. No primary outcome measurement was listed in the supplied record. Reported outcomes were measured through week 48 and included ventilatory efficiency, NT-proBNP, New York Heart Association (NYHA) class, symptom burden, health status, and peak oxygen consumption.

Key results

At week 48, the least-squares mean change from baseline in VE/VCO2 slope was -0.64 ratio in Treatment 1, with a standard error of 0.608, versus 0.16 ratio in Treatment 2, with a standard error of 0.603. An ANCOVA analysis reported an LSM difference of -0.81, with a 95% confidence interval of -2.21 to 0.6.

The percentage of participants with at least one NYHA class improvement was 36.33% in Treatment 1 and 31.62% in Treatment 2. The reported risk difference was 5.01 percentage points, with a 95% confidence interval of -2.25 to 12.23. HCMSQ shortness-of-breath scores changed by -1.76 versus -1.06, with standard errors of 0.208 and 0.207; the corresponding ANCOVA LSM difference was -0.7, with a 95% confidence interval of -1.18 to -0.22.

KCCQ-23 clinical summary scores changed by 13.13 points in Treatment 1 and 10.38 points in Treatment 2. Peak VO2 changed by 0.52 mL/kg/min versus 0.05 mL/kg/min. The reported p-values for analyses of these measures were 0.056 and 0.066, with 95% confidence intervals of -0.08 to 5.56 and -0.03 to 0.98, respectively. No adverse-event summary was supplied.

What this means

The posted results showed numerically greater improvement with Treatment 1 across several reported week-48 measures, including symptom burden, health status, NYHA class, and peak oxygen consumption. However, the supplied analyses included confidence intervals crossing zero for several comparisons, and the data block does not identify which numbered treatment group corresponded to mavacamten or placebo. The results alone do not establish a regulatory decision or provide a complete safety assessment.

Source

Source: ClinicalTrials.gov, trial-results record for NCT05582395, posted 20 August 2026. The registry record is available at clinicaltrials.gov/study/NCT05582395.