Mavacamten in Symptomatic Nonobstructive Hypertrophic Cardiomyopathy

Mavacamten is approved to treat adults with symptomatic obstructive hypertrophic cardiomyopathy (HCM). However, its effects in nonobstructive HCM remain uncertain.

We conducted a phase 3, international, double-blind, placebo-controlled, clinical trial to determine whether mavacamten improves functional capacity and patient-reported health status among adults with symptomatic nonobstructive HCM. Patients were randomly assigned in a 1:1 ratio to receive mavacamten (starting at 5 mg per day and adjusted up to a maximum of 15 mg per day on the basis of left ventricular ejection fraction) or placebo (with sham dose adjustment) for 48 weeks. The two primary end points were the change from baseline to week 48 in peak oxygen uptake and in the 23-item Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS; scores range from 0 to 100, with higher scores indicating better health status).