FDA Approves Camzyos (Mavacamten) for Children With Obstructive HCM — the First Drug-Era Option for Adolescents With the Disease

FDA Approves Camzyos (Mavacamten) for Children With Obstructive HCM — the First Drug-Era Option for Adolescents With the Disease

September 30, 2026. The FDA approved an expanded indication for Bristol Myers Squibb's Camzyos (mavacamten), making it "the first treatment for children with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) to improve functional capacity and symptoms¹," now approved for adults and pediatric patients weighing at least 30 kg (FDA, Sept 30, 2026). BMS says mavacamten is now "the only FDA-approved therapy for oHCM in a pediatric population" and has the broadest indication of any cardiac myosin inhibitor (HCPLive).

The evidence: approval rests on the Phase 3 SCOUT-HCM trial (NCT06253221) — 44 adolescents aged 12 to <18, randomized 1:1 to mavacamten or placebo for 28 weeks. The primary endpoint hit decisively: Valsalva LVOT gradient fell a mean of 49.4 mm Hg with mavacamten vs 1.8 mm Hg with placebo (least-squares mean difference −48.0 mm Hg; 95% CI −67.7 to −28.3; P < .0001). Resting and post-exercise gradients, maximal LV wall thickness, and E/e′ all improved; no patient developed LVEF <50%, no adverse event led to discontinuation, and there were no deaths, symptomatic heart failure, or atrial fibrillation during the placebo-controlled period. Full results were published in NEJM in March 2026.

Safety framing carries over: the label retains the boxed warning for heart failure from systolic dysfunction, and the drug remains available only through the Camzyos REMS, with pediatric dosing adding a 1-mg step for CYP2C19/CYP3A4 inhibitor interactions.

Why it matters: adolescents with oHCM have until now been treated with β-blockers, calcium channel blockers, and disopyramide extrapolated from adult data. SCOUT-HCM principal investigator Joseph Rossano (CHOP) called the approval "a landmark moment for pediatric cardiology… For the first time, children with this serious condition have a therapy that is FDA-approved to reduce left ventricular outflow tract obstruction."