OBJECTIVES: Little has been studied about the quality of life (QoL) of patients with obstructive hypertrophic cardiomyopathy (HCM) in China. This analysis explores the modelled QoL of Chinese patients with symptomatic (New York Heart Association [NYHA] class II-III) obstructive HCM by utilizing data from the EXPLORER-CN trial (NCT05174416).

METHODS: In EXPLORER-CN, 54 and 27 patients were randomized to either mavacamten + SoC (including beta blockers or calcium channel blockers) vs placebo + SoC respectively. collected from a related trial, EXPLORER-HCM (NCT03470545), was previously used in cost-effectiveness analyses of mavacamten + SoC in obstructive HCM patients. EQ-5D was not collected in EXPLORER-CN, so a mapping algorithm (Thomas et al., 2021) was applied, converting Kansas City Cardiomyopathy Questionnaire-23 (KCCQ) (a validated QoL measure for obstructive HCM patients) to index scores.

RESULTS: Mapped utility for NYHA class I was 0.91; mean difference in EQ-5D for NYHA class II and III were -0.03 and -0.07, increasing to -0.06 and -0.21 after adjustment. For mapped EQ-5D, estimated mean change in utility from baseline to Week 30 was 0.04 (95% confidence interval [CI] 0.005, 0.07) and -0.04 (95% CI -0.07, -0.01) for mavacamten and placebo patients respectively.

CONCLUSIONS: The EXPLORER-CN trial highlights the QoL burden of patients with symptomatic obstructive HCM, with mavacamten having the potential to improve patients QoL in the long-term through improvements in symptomatic status.