Mavacamten – a novel myosin inhibitor – "markedly improved" the health status of patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) vs. placebo, according to an analysis of the EXPLORER-HCM trial presented May 15 during ACC.21 and simultaneously published in The Lancet.

John A. Spertus, MD, MPH, FACC, et al., conducted a health status analysis of the EXPLORER-HCM trial, which enrolled and randomly assigned 251 patients to received once daily mavacamten or placebo for 30 weeks. The primary outcome for the analysis was self-reported health status measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ), which was administered at baseline and weeks 6, 12, 18, 30, and 38. Changes from baseline to week 30 in KCCQ overall summary (OS) score and all subscales were analyzed using mixed model repeated measures.

Results showed the change in KCCQ-OS score was greater with mavacamten vs. placebo (p<0.0001) at 30 weeks, with similar benefits across all KCCQ subscales. The proportion of patients with a very large change was 36% (33 of 92) in the mavacamten group vs. 15% (13 of 88) in the placebo group, with an estimated absolute difference of 21% and number needed to treat of five. These gains returned to baseline after treatment was stopped.

The authors explain that they "found substantial changes in KCCQ scores in patients given mavacamten, with the greatest benefits being on the physical limitation scale, followed by symptoms, quality of life, and social limitations, resulting in very large benefits in the overall health status of patients with obstructive hypertrophic cardiomyopathy."

"These data can support better explanations to patients about the benefits of treatment and align well with the 2020 treatment guidelines for obstructive hypertrophic cardiomyopathy, which underscore the importance of shared decision-making," the authors conclude.

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: ACC Annual Scientific Session, ACC21, Heart Failure, Cardiomyopathies

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