Mavacamten, a potential first-in-class cardiac myosin inhibitor for patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), showed improvement in health status compared to placebo at 30 weeks in EXPLORER-HCM trial

Findings of new analysis published simultaneously in The Lancet

PRINCETON, N.J.--(BUSINESS WIRE)-- Bristol Myers Squibb (NYSE: BMY) today announced a new analysis of data from the Phase 3 EXPLORER-HCM study evaluating mavacamten, an investigational, first-in-class cardiac myosin inhibitor, in patients with obstructive hypertrophic cardiomyopathy (oHCM), which was presented at the American College of Cardiology’s 70th Annual Scientific Session (ACC.21), with simultaneous publication in The Lancet. At 30 weeks, the change in Kansas City Cardiomyopathy Questionnaire Overall Summary Score (KCCQ OSS) was greater in mavacamten patients than placebo, with similar benefits across all KCCQ subscales. Moreover, a greater proportion of mavacamten patients achieved a very large, clinically meaningful improvement (≥20 points) in the KCCQ OSS, compared to placebo, 36% [33/92] vs. 15% [13/88]. A change of at least 5 points is required to be considered clinically significant. These results were presented today as part of the Featured Clinical Research I Session (403-09) in the Hot Topics Channel from 12:15-1:30 p.m. EDT.

“The KCCQ is a 23-item disease-specific questionnaire quantifying symptoms, physical function, social function and quality of life. By using this tool, we were able to demonstrate substantial clinical benefits for patients taking mavacamten in the trial, which diminished when patients ended treatment,” said lead study investigator, John A. Spertus, M.D., M.P.H., Clinical Director of Outcomes Research at Saint Luke’s Mid America Heart Institute and the Lauer Missouri Endowed Chair and Professor of Medicine at the University of Missouri–Kansas City. “This new analysis of the EXPLORER-HCM data provides important insights into the benefits myosin inhibition can have in improving the health status of patients with severe obstructive hypertrophic cardiomyopathy, a chronic, often debilitating condition.”

In the Phase 3, double-blind, placebo-controlled trial, patients with symptomatic oHCM (LVOT gradient ≥50 mmHg and NYHA Class II-III) were randomized 1:1 to mavacamten (n=123) or placebo (n=128) for 30 weeks, followed by an 8-week washout. The KCCQ was administered at baseline and Weeks 6, 12, 18, 30 and 38. Change from baseline in KCCQ scores were analyzed using mixed model repeated measures and responder analyses.

A total of 92 patients randomized to mavacamten and 88 randomized to placebo completed the KCCQ at both baseline and Week 30 (end of treatment).

Findings include:

• At 30 weeks, the change in KCCQ OSS was greater with mavacamten than placebo (mean ± SD, 14·9±16 vs. 5·4±14; difference=9·1 (95%CI: 5·5-12·8; p