TCTAP A-093 Role of Cardiac Myosin Inhibitors in the Treatment of Hypertrophic Cardiomyopathy: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Hypertrophic cardiomyopathy (HCM) is the most prevalent hereditary cardiac condition globally. The existing pharmaceutical therapy choices are limited. Cardiac myosin inhibitors (CMIs), including mavacamten and aficamten, address the primary underlying pathophysiology of HCM. However, the degree of their effectiveness and safety remains uncertain owing to the restricted population examined.

Methods

Following Prisma guidelines (Figure 1), we executed an extensive search on several electronic databases, including PubMed, Scopus, Cochrane, and Web of Science, to find RCTs that assessed the effectiveness and safety of CMIs in HCM. A meta-analysis using the Netmeta package in R studio 4.3.2 was performed. Continuous data were pooled using mean differences (MD) whereas dichotomous data were analyzed using risk ratios (RR) with 95 % confidence intervals (CIs).

Results

Six RCTs with 826 patients participated, 53.6 % (443) were assigned to the CMIs group and 46.4 % (383) served as controls. Four trials focused on mavacamten, while two concentrated on aficamten. Notably, five trials involved patients diagnosed with hypertrophic obstructive cardiomyopathy (oHCM), whereas one included only patients with hypertrophic non-obstructive cardiomyopathy (noHCM). CMIs were linked to a significantly higher rate of ≥1 NYHA class improvement compared to placebo (RR: 2.21, 95 % CI: 1.84, 2.66; p < 0.0001; I2= 25.3 % ; Figure 2), and change from baseline in Clinical Summary Score of the Kansas City Cardiomyopathy Questionnaire score (KCCQ-CSS) (MD: 7.20, 95 %CI: 4.65, 9.75; p = 0.025; I2= 45.4 % ; Figure 3). In sub-group analysis, patients with oHCM attained higher rates of ≥1 NYHA class improvement (RR:2.33, 95 % CI: 1.92, 2.82) and improvement in KCCQ-CSS scores (MD: 7.85, 95 %CI: 5.59, 10.12) compared to noHCM patients. CMIs were also linked to improvement in resting left ventricular outflow tract (LVOT) gradient (MD: -37.40, 95 % CI: – 44.28, – 30.53; p < 0.0001; I2 = 65.9 % ; Figure 4 ), Valsalva LVOT gradient(MD: – 47.44, 95 % CI: – 59.85, – 35.04; p < 0.0001; I2= 84.3 %), postexercise LVOT gradient (MD: – 37.11, 95 % CI: – 44.34, – 29.87; p <0.0001; I2 = 0 %), Left ventricular mass index (LVMI) (MD: – 16.83, 95 %CI: – 30.28, – 3.38; p = 0.014; I2 = 87.5 %), and lower rates of Septal reduction therapy (SRT) (RR: 0.30, 95 % CI: 0.22, 0.40; p < 0.0001; I2 = 0 %), but also there was a decline in left ventricular ejection fraction (LVEF) (MD:- 4.15, 95 % CI: – 5.20, – 3.10; p < 0.0001; I2 = 42.5 %). There were no significant differences between CMIs and placebo in the composite functional outcome, ≥1 treatment-emergent adverse event, ≥1 serious adverse event, atrial fibrillation, and any score LVEF < 50%.

Conclusion

Our meta-analysis demonstrated that CMIs (mavacamten, aficamten) improved NYHA class, KCCQ-CSS scores, LVOT gradients, and LVMI. Simultaneously lowering the frequency of SRT in patients with HCM. There was a significant decline in LVEF. New large-scale multicenter RCTs are required to confirm or refute our findings and provide more reliable results.