Mavacamten in a real-world hypertrophic cardiomyopathy population: how many may be eligible?

Abstract Introduction Mavacamten is a newly approved drug for obstructive hypertrophic cardiomyopathy (oHCM) and is currently being studied in non-obstructive HCM (nHCM). Our goal was to evaluate how often patients with oHCM and nHCM in a real-world cohort would be eligible for the main mavacamten trials: EXPLORER-HCM, VALOR-HCM and MAVERICK-HCM. Methods Single-centre retrospective study enrolling consecutive patients with confirmed HCM, as per the 2023 ESC Guidelines, with at least yearly follow-up in our center, from 2017-2023. Key inclusion criteria from the three trials were considered: NYHA class II-III for all; obstructive forms (defined as peak left ventricle outflow tract [LVOT] gradient ≥50 mmHg at rest, after Valsalva manoeuvre or exercise) for EXPLORER-HCM and VALOR-HCM; left ventricular ejection fraction (LVEF) ≥55% for EXPLORER-HCM and MAVERICK-HCM; LVEF ≥60% and formal criteria for septal reduction therapy for VALOR-HCM, and NT-proBNP ≥300pg/mL for MAVERICK-HCM. Key exclusion criteria (estimated glomerular filtration rate [eGFR] <30mL/kg/1.73m2, QTc using the Fridericia’s formula >500ms, paroxysmal or intermittent atrial fibrillation present on screening electrocardiograph) were also considered. Results Overall, 410 patients were diagnosed with HCM, of whom 361 (88%) were alive at follow-up and included in the analysis: mean age of 63 ± 16 years, 196 (54%) were male, 272 (75%) with septal HCM and 60 (17%) with oHCM. According to the criteria of EXPLORER-HCM, VALOR-HCM and MAVERICK-HCM, 35 (10%), 6 (2%) and 27 (7%) patients would be eligible for enrolment, respectively. In patients with oHCM, 35 (58%) would be eligible for the EXPLORER-HCM trial. In the overall cohort, 65 (18%) would have criteria for at least one of the trials. The main reasons for exclusion were as follows: 191 (53%) NYHA I, 43 (12%) with NYHA IV, 12 (3%) had a LVEF <55%, 8 (2%) had both HCM and infiltrative myocardial disease and/or moderate-to-severe aortic stenosis and 8 (2%) had an eGFR <30mL/kg/1.73m2. In patients with nHCM, 16 (5%) would have been excluded due to NT-proBNP <300pg/mL and 8 (3%) due to paroxysmal atrial fibrillation. Conclusion In a real-word HCM cohort, we found that approximately 1 in every 5 patients would have criteria for either of the mavacamten trials, with more than half of oHCM being potential candidates for the EXPLORER-HCM. The main reasons for non-eligibility were NYHA I and LVEF <55%.