FDA Approval of Mavacamten for Adolescents Addresses Massive Unmet Need

On September 30, 2026, the US Food and Drug Administration (FDA) approved mavacamten for symptomatic obstructive hypertrophic cardiomyopathy (oHCM) in pediatric patients.1

Mavacamten was first approved in 2022 for adults with symptomatic oHCM to improve functional capacity and symptoms. Parent company Bristol Myers Squibb has reported that mavacamten has since been prescribed to >25,000 patients in the US. This approval establishes mavacamten as having the broadest indication of any approved cardiac myosin inhibitor (CMI) and addresses a population with significantly unmet need.1

“I think this is paradigm-shifting as a proof of concept, that disease-specific therapies targeted to the underlying pathophysiology of the disease can be developed for use in children with cardiovascular disorders," Joseph Rossano, MD, MS, co-director of the cardiac center and chief of the division of cardiology at the Children’s Hospital of Philadelphia and lead author on the SCOUT-HCM trial, told HCPLive in an exclusive interview. “This is essentially the first time that we’ve had that, and I think it’s incredibly exciting for these patients, but maybe even more so for the field – it shows us what’s possible.”

The FDA’s approval was based on positive results from the SCOUT-HCM trial, a phase 3, double-blind, randomized, placebo-controlled trial comparing mavacamten to placebo in patients aged 12 to <18. Patients were eligible for inclusion if they had a diagnosis of HCM, left ventricular outflow tract (LVOT) obstruction, and recorded symptoms. Patients were excluded from the trial if they displayed left ventricular ejection fraction (LVEF) <50%, phenocopy diseases resulting in myocardial hypertrophy unrelated to sarcomere dysfunction, or planned HCM therapy escalation.2,3

Following enrollment, patients were randomly assigned in a 1:1 ratio to either mavacamten or placebo. Mavacamten treatment began on day 1 and could be escalated from 1 mg to 15 mg, while placebo treatment was initiated from week 1 to week 28 before patients were switched to mavacamten during week 28. The trial continued for 200 weeks, with a primary outcome of change from baseline in Valsalva LVOT gradient at week 28. Secondary endpoints included change from baseline in resting LVOT gradient, change in post-exercise peak LVOT gradient, and change in maximal wall thickness, among others.3

A total of 44 patients were enrolled in the trial, of whom 23 received mavacamten and 21 received placebo. The mean age (+/- standard deviation [SD]) of patients was 14.7 +/- 1.7 years in the mavacamten arm and 14.6 +/- 1.7 years in the placebo arm. Mean Valsalva LVOT gradient was similar in both arms at baseline (78.4 +/- 34.1 mmHg and 80.8 +/- 47.4 mmHg, respectively).2

By week 28, the least-squares mean change in Valsalva LVOT gradient was -48.5 mmHg in the mavacamten arm and -0.5 mmHg in the placebo group (difference, -48 mmHg; 95% CI, -67.7 to -28.3; P <.001). Adverse events were similar between both groups – 2 patients in each arm had a serious adverse event. The mavacamten arm saw 1 patient experience 2 episodes of syncope, while another had an inappropriate shock from an implantable cardioverter-defibrillator; the placebo arm saw 1 patient with chest pain and another with suicidal ideation. No patients had a reduction in LVEF to <50%.2

Ultimately, investigators concluded that LVOT obstruction saw significantly greater reductions with mavacamten compared to placebo. This led to the FDA’s approval in this population, expanding mavacamten’s indication and allowing a patient population with few treatment options a way of managing and improving their conditions.1,2,3

“There’s huge unmet need in pediatric cardiology that certainly extends to other forms of cardiomyopathies, but also for all other sorts of pediatric cardiovascular disorders like congenital heart disease, and we really don’t have disease-specific therapies for these patients,” Rossano said. “I’m excited about the future – it’s possible for us to develop disease-specific therapies that can be successful. Mavacamten really just opens up the door for possibilities.”

Editors’ Note: Rossano reports disclosures with Astellas, Bayer, Bristol Myers Squibb, CRI Biotech, Merck, and AskBio.

References

1. Bristol Myers Squibb. 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. 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. Rossano JW, Canter C, Wolf CM, et al. Mavacamten in adolescents with obstructive hypertrophic cardiomyopathy. New England Journal of Medicine. 2026;395(4):362-373. doi:10.1056/nejmoa2601103

3. Bristol Myers Squibb. A Study to Evaluate Mavacamten in Adolescents With Symptomatic Obstructive Hypertrophic Cardiomyopathy. ClinicalTrials.gov Identifier: NCT06253221. Updated December 19, 2025. Accessed October 1, 2026. https://clinicaltrials.gov/study/NCT06253221