Mavacamten Monotherapy in Real-World Patients With Obstructive Hypertrophic Cardiomyopathy: Evidence From COLLIGO-HCM

BACKGROUND: – Mavacamten has been shown to improve cardiac function and symptoms in patients with symptomatic (New York Heart Association class II–III) obstructive hypertrophic cardiomyopathy (HCM). Clinical studies suggest that mavacamten monotherapy is efficacious and has a favorable safety profile, but limited evidence exists regarding monotherapy in real-world studies. This analysis aimed to describe the effectiveness and safety outcomes of mavacamten monotherapy in the real-world COLLIGO-HCM (Mavacamten ObservationaL Evidence Global Consortium in Hypertrophic Cardiomyopathy). METHODS: – Patient-level data recorded between April 2022 and February 2025 at 7 sites across 5 countries were extracted. Adult patients with a diagnosis of HCM from 2018 onwards were eligible for inclusion if they had ≥1 mavacamten prescription after the date of diagnosis. Patients were categorized based on background therapy status during mavacamten treatment: mavacamten monotherapy or mavacamten with background therapy (down-titration or no dose modification). RESULTS: – Overall, 278 patients were included and received mavacamten (mavacamten monotherapy, n=88; mavacamten with background therapy, n=190). At month 9, most patients achieved ≥1 NYHA class improvement from baseline (mavacamten monotherapy, 60.0%; mavacamten with background therapy, 61.0%). Improvements in resting and Valsalva left ventricular outflow tract gradients from baseline to month 9 were observed in both subgroups; mean left ventricular ejection fraction through month 9 remained ≥62.0% with mavacamten monotherapy and ≥61.4% with mavacamten with background therapy. Two patients in the mavacamten monotherapy subgroup and 1 patient in the mavacamten with background therapy subgroup permanently discontinued treatment owing to left ventricular ejection fraction <50%. CONCLUSIONS: – Mavacamten monotherapy was associated with improvements in cardiac function and symptoms, and positive benefits to the risk profile over a 9-month follow-up period; this was consistent with improvements observed in patients treated with mavacamten with background therapy. REGISTRATION: – URL: https://www.clinicaltrials.gov; Unique identifier: NCT06372457.