Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM

CY 6031 was a Phase 3, randomized, placebo-controlled, double-blind, multi-center trial in participants with symptomatic oHCM. Eligible participants were randomized in a 1:1 ratio to receive aficamten or placebo. Randomization was stratified by use of beta-blockers (yes or no) and cardiopulmonary exercise testing (CPET) exercise modality (treadmill or bicycle). Enrollment limits were applied as follows: participants taking beta-blockers were capped at approximately 70% of total enrollment; participants taking disopyramide were capped at approximately 10% of total enrollment; participants with persistent atrial fibrillation (AF) at screening were capped at approximately 15% of total enrollment; and participants using the bicycle CPET exercise modality were capped at approximately 50% of total enrollment.

Investigational product (IP) was administered orally once daily (QD) with or without food for 24 weeks. During the initial 6 weeks of the treatment period, IP doses were individually titrated at Weeks 2, 4, and 6 based on echocardiography-guided criteria. Dose escalation at Weeks 2, 4, and 6 occurred only if a participant had a Valsalva left ventricular outflow tract gradient (LVOT-G) ≥ 30 mmHg and a biplane left ventricular ejection fraction (LVEF) ≥ 55%. Echocardiograms were performed at each subsequent visit during the trial, and the IP dose was down-titrated if the LVEF was \< 50%. The primary endpoint of peak oxygen uptake (pVO2) was measured by CPET at screening and at the end of treatment (Week 24). A participant's background HCM therapy was individually optimized according to local practice prior to enrollment in the study.