Real-world outcomes of mavacamten in obstructive hypertrophic cardiomyopathy (HCM) in the United States: a pooled analysis

Background

Real-world clinical outcomes with mavacamten in obstructive HCM have been reported mostly by individual HCM centres, resulting in limited sample size and generalizability. This highlights the need for synthesizing data across multiple centres to obtain robust and nationally representative findings.

Purpose

To evaluate changes in echocardiographic parameters and New York Heart Association (NYHA) functional class following mavacamten initiation in patients with obstructive HCM across multiple centres using real-world data from published studies.

Methods

A comprehensive targeted literature review was conducted to identify peer-reviewed articles and congress abstracts published through March 31, 2025, that reported real-world outcomes of mavacamten from US HCM centres. Eligible studies included patients with obstructive HCM treated with mavacamten and reported echocardiographic and NYHA outcomes. Data on baseline characteristics and post-treatment changes were extracted and pooled.

Results

Thirteen eligible studies, encompassing data from 14 HCM centres across the US (5 in the West, 3 in the East, 2 in the Midwest, and 4 in the South), were included in the analysis. The pooled cohort (mean ± SD age: 62.6 ± 13.5 years; 53.8% female; 76.3% White) was primarily NYHA class II (42.2%) and III (56.4%) at baseline (Table). Resting and Valsalva left ventricular outflow tract (LVOT) gradients declined substantially by week 4, with sustained reductions through week 60 (Figure 1A). Left ventricular ejection fraction (LVEF) decreased modestly, with a mean ± SD reduction of -6.0% ± 7.8% at week 60. NYHA functional improvement was substantial, with 22.2% of patients reaching class I by week 4 and 60.0% by week 60 (Figure 1B). Improvement of ≥1 NYHA class was observed in 67.5% of patients at week 12 and 91.7% at week 60; ≥2 class improvement was seen in 22.5% at week 24.

Conclusions

This pooled analysis of real-world studies confirms the early and sustained effectiveness of mavacamten in reducing LVOT obstruction below the guideline-established threshold for obstruction and improving symptoms to achieve asymptomatic status in patients with obstructive HCM.

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