Mavacamten, a First-in-Class Cardiac Myosin Inhibitor for Obstructive Hypertrophic Cardiomyopathy

To assess mavacamten's role in hypertrophic cardiomyopathy treatment.

In addition to clinical guidelines, package inserts, and general reviews, we searched PubMed using the term mavacamten from inception to June 11, 2022.

English language studies describing mavacamten's mechanism of action, pharmacokinetics, drug interactions, clinical and economic outcomes, and adverse events.

Mavacamten reduces left ventricular outflow obstruction and New York Heart Association functional class while improving Kansas City Cardiomyopathy Questionnaire-Clinical Summary Scores in patients with obstructive hypertrophic cardiomyopathy. With an acquisition cost of $245.20 per capsule, it would cost $1.2 million for every additional quality-adjusted life year. In those with unobstructive hypertrophic cardiomyopathy, there were improvements in N-terminal probrain natriuretic peptide and high-sensitivity cardiac troponin biochemical markers. Mavacamten is a substrate for CYP2C19 and CYP3A4, and a CYP enzyme inducer.

Patients with obstructive hypertrophic cardiomyopathy and an ejection fraction ≥55% have a new option if they remain symptomatic despite maximally tolerated β-blocker or non-dihydropyridine calcium channel blocker therapy. It is an alternative to disopyramide therapy, which has poor patient tolerance, or septal reduction therapies, which are invasive. However, mavacamten is not cost-effective and its role in nonobstructive hypertrophic cardiomyopathy is not well established.

Mavacamten is a new option for patients with refractory obstructive hypertrophic cardiomyopathy and an ejection fraction ≥55% but its pricing makes therapy not cost-effective. Final health outcomes are not fully elucidated and additional studies are needed to determine long-term effects.