Real-World Effectiveness of Mavacamten in Canada: Insights from the MAVEN Study.

INTRODUCTION

Previous studies have demonstrated the efficacy and safety of mavacamten in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), primarily outside of Canada, with limited Canadian real-world data evidence. The MAVEN study aimed to describe the real-world effectiveness of mavacamten in Canadian patients with oHCM.

METHODS

This multi-center, retrospective physician survey of patient charts included 115 patients with oHCM who initiated mavacamten between January 2023 and November 2024 across five Canadian sites. Effectiveness was assessed by changes in clinical characteristics and outcomes, including New York Heart Association (NYHA) functional class, resting and Valsalva left ventricular outflow tract (rLVOT and vLVOT, respectively) gradients, and left ventricular ejection fraction (LVEF), from treatment initiation to the most recent available assessment.

RESULTS

Baseline demographic and clinical characteristics were consistent with previously published data (median age 63.0 years; 66.1% aged ≥ 60 years; 51.3% male, 48.7% female patients; 57.4% NYHA class II, 42.6% NYHA class III). Median baseline rLVOT and vLVOT gradients were 44.0 and 78.0 mmHg, respectively, and median LVEF was 65.0%. Overall, 72.7% of patients improved by ≥ 1 NYHA functional class. Median reductions in rLVOT and vLVOT gradients were - 25.5 (interquartile range [IQR]: - 61, - 8) mmHg and - 51.0 (IQR: - 83, - 24) mmHg, respectively, while median LVEF changed by - 3.0% (IQR: - 8, 0). Mavacamten was discontinued in 8.7% of patients, including 2.6% due to treatment-emergent adverse events. Reductions in LVEF < 50% were observed in 6.1% of patients, and no patient experienced an LVEF < 30%.

CONCLUSIONS

In this first Canadian real-world study of mavacamten effectiveness, treatment was associated with improvements in symptoms and LVOT obstruction. Reductions in LVEF < 50% were observed in a minority of patients, with no cases of LVEF < 30%. Given the retrospective design and heterogeneous follow-up of this study, these findings should be interpreted cautiously. Graphical abstract available for this article.