OBJECTIVES

Treatment with mavacamten significantly improved the New York Heart Association (NYHA) functional class in patients with obstructive hypertrophic cardiomyopathy (oHCM) in the EXPLORER-HCM clinical trial. This study assessed the effects of mavacamten on patient health-related quality of life (HRQoL) and estimated the utilities for health states defined by NYHA class for these patients.

METHODS

Patients with symptomatic oHCM enrolled in the 30-week EXPLORER-HCM clinical trial were randomized to receive mavacamten or placebo. Health utility was estimated using the EQ-5D-5L domain scores and the US value set. Changes in EQ-5D-5L Index Value and EQ-VAS from baseline to week 30 were compared between mavacamten and placebo using linear regressions adjusting for baseline NYHA class (II or III), current treatment with beta-blocker, and type of ergometer (treadmill or exercise bicycle). Additionally, mean utilities for the NYHA classes (I, II, and III/IV) were estimated for mavacamten and placebo, respectively, using data from all visits with a generalized estimating equation model.

RESULTS

Patients in the mavacamten arm (N = 96) had significantly greater improvement from baseline to week 30 in EQ-5D-5L Index Value (adjusted difference: 0.073) and EQ-VAS (adjusted difference: 7.5) than patients in the placebo arm (N = 89) (both p<0.05). For patients in the mavacamten arm (N = 123), the mean utilities were 0.950, 0.866, and 0.708 for NYHA class I, II, and III/IV, respectively. The corresponding mean utilities for placebo (N = 128) were 0.952, 0.850, and 0.704, respectively. The mean utilities were significantly different across NYHA classes in each treatment arm. Within each NYHA class, the mean utilities were similar between the two arms.

CONCLUSIONS

Treatment with mavacamten significantly improved EQ-5D-5L Index Value and EQ-VAS—and thus HRQoL— in patients with oHCM. Additionally, patients in a worse NYHA class had lower health utility.