Nonobstructive Heart Enlargement Responds to Aficamten

Aficamten, a cardiac myosin inhibitor, has demonstrated promising results in improving exercise capacity and health status of patients with symptomatic nonobstructive hypertrophic cardiomyopathy (HCM) in a large-scale trial. This phase III study, ACACIA-HCM, met both primary endpoints, showing significant improvements in peak oxygen uptake and patient-reported health status compared to placebo.

At 36 weeks, aficamten patients experienced a 0.67 mL/kg/min increase in peak oxygen uptake, while placebo patients saw a minimal decrease of 0.03 mL/kg/min. Additionally, aficamten treatment led to an average 3.0-point increase in the Kansas City Cardiomyopathy Questionnaire clinical summary score, compared to an 8.4-point increase in placebo patients.

The trial also revealed secondary benefits, including improvements in heart failure symptoms, patient-reported health status, and biomarkers such as NT-proBNP levels. While the magnitude of benefit in the nonobstructive HCM group was modest compared to previous treatments in obstructive HCM, aficamten's overall safety profile and potential for a tailored therapeutic approach based on patient characteristics are noteworthy.