For patients with obstructive hypertrophic cardiomyopathy (oHCM), mavacamten can reduce left ventricular outflow tract (LVOT) obstruction, improve exercise capacity, and improve symptoms, according to results published in the Annals of Internal Medicine.

Mavacamten is a first-in-class small molecule allosteric modulator of cardiac myosin that is administered orally.

The study included participants with symptomatic oHCM. Participants received either mavacamten 10 to 20 mg daily without background medications (group A) or mavacamten 2 to 5 mg daily with beta-blockers allowed (group B). The primary end point was change in postexercise LVOT gradient at 12 weeks. Secondary end points included changes in peak oxygen consumption (pVO2), resting and Valsalva LVOT gradients, left ventricular ejection fraction (LVEF), and numeric rating scale dyspnea score.

After 12 weeks, the mean postexercise LVOT gradient in group A had been reduced from 103 mm Hg at baseline to 19 mm Hg (P =.008). Group A also had a mean reduction in resting LVEF of -15%, while pVO2 increased by a mean of 3.5 mL/kg/min.

In cohort B, the mean postexercise LVOT gradient was reduced from 86 mm Hg at baseline to 64 mm Hg after 12 weeks (P =.02). The mean change in resting LVEF was -6%, while pVO2 increased by a mean of 1.7 mL/kg/min.

The results indicated that mavacamten was well tolerated; most adverse events were mild (80%), moderate (19%), or unrelated (79%).

The most common adverse events that were definitely or possibly related to treatment were decreased LVEF at higher plasma concentrations and atrial fibrillation.

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“If confirmed in larger studies, these data suggest a potential role for mavacamten in the treatment of oHCM,” the researchers wrote.

Reference

Heitner SP, Jacoby D, Lester SJ, et al. Mavacamten treatment for obstructive hypertrophic cardiomyopathy: a clinical trial [published online April 30, 2019]. Ann Intern Med. doi:10.7326/M18-3016