FDA Expands Mavacamten Indication to Pediatric Patients With Obstructive HCM

The FDA has approved an expanded indication for mavacamten (Camzyos, Bristol Myers Squibb) for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (oHCM) to improve functional capacity and symptoms in adults and pediatric patients weighing 30 kg or more, Bristol Myers Squibb announced.

Mavacamten, a selective, reversible, allosteric cardiac myosin inhibitor, was first approved in 2022 for adults with symptomatic New York Heart Association (NYHA) class II-III oHCM. The company said it is now the only FDA-approved therapy for oHCM in a pediatric population. The FDA had accepted the supplemental new drug application for Priority Review.

The approval is based on the phase 3, randomized, double-blind, placebo-controlled SCOUT-HCM trial, which enrolled 44 patients aged 12 to younger than 18 years with symptomatic NYHA class II-III oHCM, a left ventricular ejection fraction (LVEF) of 60% or higher, and a Valsalva left ventricular outflow tract (LVOT) gradient of at least 30 mm Hg. Patients received once-daily mavacamten (n=23) or placebo (n=21) for 28 weeks; background beta blockers, calcium channel blockers, or disopyramide were permitted. At week 28, the mean Valsalva LVOT gradient fell by 49.4 mm Hg with mavacamten vs 1.8 mm Hg with placebo (least-squares mean difference, −48.0 mm Hg; P<.0001).

No patients had an LVEF below 50%, and no adverse events led to discontinuation. Serious adverse events occurred in 2 patients in each group (9% vs 10%), and no new adverse reactions were identified beyond the adult safety profile. The prescribing information carries a boxed warning for heart failure due to systolic dysfunction, requires echocardiographic LVEF assessment before and during treatment, and restricts access through the Camzyos Risk Evaluation and Mitigation Strategy (REMS) Program. Use with strong CYP2C19 inhibitors or moderate to strong CYP2C19 or CYP3A4 inducers is contraindicated.

Secondary endpoints were summarized descriptively without adjustment for multiplicity. SCOUT-HCM continues with a 28-week active-treatment period and an open-label extension of up to 144 weeks. According to the company, the pediatric data are being discussed with other regulatory authorities.

Source: Bristol Myers Squibb. US Food and Drug Administration approves expanded indication for Bristol Myers Squibb's Camzyos (mavacamten) for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (oHCM) in adults and pediatric patients. Press release. Bristol Myers Squibb; September 30, 2026. Accessed October 1, 2026.