FDA Expands Mavacamten Label to Include Children With oHCM

Mavacamten (Camzyos; Bristol Myers Squibb) is now approved to improve functional capacity and symptoms in adults and pediatric patients weighing at least 66 lb with symptomatic obstructive hypertrophic cardiomyopathy (oHCM), making it the only FDA-approved therapy for oHCM in a pediatric population, according to Bristol Myers Squibb.¹

The cardiac myosin inhibitor (CMI) was first approved in 2022 for adults with symptomatic NYHA class II-III oHCM. The company said the expanded label gives mavacamten the broadest indication of any CMI and that it is discussing the pediatric data with other regulators worldwide.

Last, findings from the EXPLORER-LTE cohort of the MAVA-LTE study (NCT03723655) were presented in a late-breaking session at the European Society of Cardiology Congress 2026 in Munich, Germany.² Five-year EXPLORER-LTE (NCT03470545) data show sustained left ventricular outflow tract gradient (LVOT) reductions and New York Heart Association class improvements in patients with obstructive HCM.

"The FDA approval of Camzyos for pediatric patients with symptomatic obstructive hypertrophic cardiomyopathy represents a landmark moment for pediatric cardiology," Joseph Rossano, MD, principal investigator of SCOUT-HCM and chief of the Division of Cardiology at Children's Hospital of Philadelphia, said in a statement.¹ "For the first time, children with this serious condition have a therapy that is FDA-approved to reduce left ventricular outflow tract obstruction."

SCOUT-HCM Cut Valsalva LVOT Gradient by 48 mm Hg vs Placebo

SCOUT-HCM (NCT06253221) was a phase 3, randomized, double-blind, placebo-controlled international trial of 44 adolescents aged 12 to younger than 18 years with symptomatic NYHA class II-III oHCM. Patients received once daily mavacamten (n = 23), started at 2.5 mg for those weighing about 77 to less than 99 lb or 5 mg for those weighing about 99 lb or more, or placebo (n = 21) for 28 weeks. Background therapy was permitted. Most patients were taking a β-blocker at baseline (83% and 86%, respectively). Placebo recipients then cross over to mavacamten for 28 weeks, followed by an open-label extension of up to 144 weeks.

At week 28, the least-squares mean Valsalva LVOT gradient fell by 48.5 mm Hg with mavacamten vs 0.5 mm Hg with placebo (difference, −48.0 mm Hg; 95% CI, −67.7 to −28.3; P < .001), according to results published in The New England Journal of Medicine.³

Secondary end points also favored mavacamten, including resting LVOT gradient (difference, −47.0 mm Hg; 95% CI, −62.7 to −31.4), postexercise LVOT gradient (−41.7 mm Hg; 95% CI, −59.7 to −23.7; 16 patients per group), and maximal left ventricular wall thickness (−1.8 mm; 95% CI, −3.4 to −0.2). These CIs were not adjusted for multiplicity and should not be read as formal hypothesis tests, the company noted.¹

No Patient Had LVEF Fall Below 50%

No patient had left ventricular ejection fraction (LVEF) fall below 50%, and no deaths occurred. Serious adverse events occurred in 2 patients in each group. In the mavacamten group, 1 patient had 2 episodes of syncope, and another received an inappropriate implantable cardioverter-defibrillator shock.² No adverse events led to discontinuation, and no new adverse reactions emerged beyond those seen in adults.¹

The label retains a boxed warning for heart failure due to systolic dysfunction. Echocardiographic LVEF assessment is required before and during treatment. Initiation is not recommended when LVEF is below 55%, and treatment should be interrupted if LVEF falls below 50% or heart failure symptoms develop. Mavacamten remains available only through a restricted Risk Evaluation and Mitigation Strategy program.

“I cannot help but think back to my 12-year-old self receiving my diagnosis and being told there were no treatment options approved specifically for my disease,” Lisa Salberg, CEO and founder of the Hypertrophic Cardiomyopathy Association, said in a statement. “This is truly a milestone moment for patients and families. Having a targeted therapy for cardiac myosin is a significant breakthrough, and it's a welcome change to bring this approval to a younger population. Thank you to all of the researchers, scientists, and the entire HCM [hypertrophic cardiomyopathy] ecosystem that has helped bring this new therapy to more patients.”

References

1. U.S. 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. News release. Bristol Myers Squibb. September 30, 2026. Accessed October 1, 2026. https://news.bms.com/news/corporate-financial/2026/U-S--Food-and-Drug-Administration-Approves-Expanded-Indication-for-Bristol-Myers-Squibbs-CAMZYOS-mavacamten-for-the-Treatment-of-Symptomatic-Obstructive-Hypertrophic-Cardiomyopathy-oHCM-in-Adults-and-Pediatric-Patients/default.aspx
2. Steinzor P. Mavacamten sustains symptom, obstruction benefits at 5 years. AJMC^®. September 1, 2026. Accessed October 1, 2026. https://www.ajmc.com/view/mavacamten-sustains-symptom-obstruction-benefits-at-5-years
3. Rossano JW, Canter C, Wolf CM, et al. Mavacamten in adolescents with obstructive hypertrophic cardiomyopathy. N Engl J Med. Published online March 29, 2026. doi:10.1056/NEJMoa2601103