Cytokinetics Gains on Positive Late-Stage Cardiomyopathy Study Results

Core Insights - Cytokinetics, Incorporated's shares increased by 40.4% on September 2 due to positive results from a phase III study of cardiovascular candidate aficamten [1] - The MAPLE-HCM study results were presented at the European Society of Cardiology Congress 2025 and published in The New England Journal of Medicine [1][2] Study Overview - The MAPLE-HCM study is a phase III randomized, double-blind, active-comparator clinical trial comparing aficamten to metoprolol in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) [3] - Aficamten is a selective, small molecule cardiac myosin inhibitor, while metoprolol is a standard beta-blocker [3] Study Results - The study enrolled 175 patients, randomized to receive either aficamten or metoprolol as monotherapy [4] - Aficamten demonstrated superiority over metoprolol on all clinically relevant efficacy endpoints, with a mean change in peak oxygen uptake (pVO2) of +1.1 mL/kg/min for aficamten compared to -1.2 mL/kg/min for metoprolol after 24 weeks [5] - The primary endpoint showed a statistically significant least-squares mean difference of 2.3 mL/kg/min between the two groups [6] - Aficamten also outperformed metoprolol in five of six secondary endpoints, improving exercise capacity, symptoms, and left ventricular outflow tract (LVOT) gradients [9] Patient Outcomes - 51% of patients receiving aficamten showed improvement in functional class compared to 26% for metoprolol [10] - Aficamten significantly improved resting LVOT gradient and Valsalva LVOT-G, with minimal reduction in left ventricular ejection fraction (LVEF) [10] Additional Data - Aficamten improved cardiac structure and function compared to metoprolol, with an annual incidence rate of atrial fibrillation at 1.5% [12] - Long-term data were consistent with the previously reported safety profile of aficamten [12] Regulatory Status - Aficamten is under FDA review, with a target decision date set for December 26, 2025 [8][13] - The FDA extended the target action date due to the submission of a Risk Evaluation and Mitigation Strategy (REMS) [14][15] Competitive Landscape - Upon approval, aficamten will compete with Camzyos (mavacamten), a first-in-class cardiac myosin inhibitor already approved by the FDA [16]