Mavacamten in Symptomatic Nonobstructive Hypertrophic Cardiomyopathy: Design, Rationale, and Baseline Characteristics of ODYSSEY-HCM

: There are no approved therapies for patients with symptomatic nonobstructive hypertrophic cardiomyopathy (nHCM). The authors describe the baseline characteristics of ODYSSEY-HCM (A Study of Mavacamten in Non-Obstructive Hypertrophic Cardiomyopathy), a phase 3, randomized, double-blind, placebo-controlled trial conducted worldwide at 201 sites evaluating mavacamten in symptomatic adult patients with nHCM. The 2 primary endpoints are the changes from baseline to week 48 in: 1) Kansas City Cardiomyopathy Questionnaire 23-item Clinical Summary Score; and 2) peak oxygen consumption (pVO2) on cardiopulmonary exercise testing. Dose titrations are made on blinded core laboratory assessments. Of 1,088 patients screened, 580 are randomized (mean age 56 ± 15 years, 46% women, 43% with family histories). All patients are nonobstructive and symptomatic (70% in NYHA functional class II and 30% class III), with a mean Kansas City Cardiomyopathy Questionnaire 23-item Clinical Summary Score of 58 ± 20, and 77% are on beta-blockers. The mean left ventricular ejection fraction and pVO2 are 66% ± 4% and 18 ± 6 mL/kg/min, respectively. ODYSSEY-HCM will report if mavacamten improves patient-reported health status and exercise capacity in patients with symptomatic nHCM. (A Study of Mavacamten in Non-Obstructive Hypertrophic Cardiomyopathy (ODYSSEY-HCM); NCT05582395).