Efficacy of Cardiac Myosin Inhibitors in Symptomatic Hypertrophic Cardiomyopathy: An Updated Meta-Analysis and Systematic Review

Abstract

Background:

This study evaluates the efficacy of cardiac myosin inhibitors (CMI), which appear to be an innovative alternative for hypertrophic cardiomyopathy (HCM), a disease lacking highly effective pharmacologic treatments.

Objective:

To provide updated efficacy data on CMI (aficamten or mavacamten) in symptomatic HCM.

Materials and methods:

We searched PubMed, Embase, and Cochrane databases for randomized controlled trials comparing CMI to placebo in symptomatic HCM, reporting: (1) New York Heart Association (NYHA) functional class improvement; (2) change from baseline in Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS); (3) percent change from baseline in left ventricular outflow tract (LVOT) gradient at rest and after Valsalva maneuver; and (4) serious adverse events. Heterogeneity was examined with I² statistics, and p values < 0.05 indicated sta tistical significance. Continuous endpoints were analyzed using pooled mean difference (MD), and binary endpoints were analyzed using odds ratios (OR), both with 95% confidence intervals (CI).

Results:

We included six RCTs with 826 patients, 443 of whom received CMI. Compared to placebo, NYHA class improvement was more frequent in patients receiving CMI (OR: 4.10; 95% CI: 2.79 to 6.02; p < 0.00001), with significant differences in KCCQ-CSS change (MD: 7.15; 95% CI: 4.21 to 10.10; p < 0.00001), as well as in LVOT gradient change at rest (MD: −38.25; 95% CI: −46.76 to −29.74; p < 0.00001) and after Valsalva maneuver (MD: −46.49; 95% CI: −54.70 to −38.27; p < 0.00001). There were no significant differences in serious adverse events (OR: 0.64; 95% CI: 0.31 to 1.31; p = 0.22).

Conclusion:

CMI shows greater efficacy than placebo in treating symptomatic HCM.