FDA Expands Camzyos Approval to Pediatric Patients With Obstructive Hypertrophic Cardiomyopathy
The U.S. Food and Drug Administration has expanded the approved use of Camzyos (mavacamten) to include adults and certain pediatric patients living with symptomatic obstructive hypertrophic cardiomyopathy, or oHCM. The expanded indication covers pediatric patients weighing at least 30 kilograms, or approximately 66 pounds.
The September 30, 2026 announcement from Bristol Myers Squibb marks an important development in the treatment landscape for younger patients with this serious heart condition. According to the company, Camzyos is now the only FDA approved therapy specifically indicated for oHCM in a pediatric population.
What Is Obstructive Hypertrophic Cardiomyopathy?
Hypertrophic cardiomyopathy, commonly called HCM, is a heart condition in which the heart muscle becomes abnormally thickened. The disease can be associated with genetic changes affecting proteins involved in the structure and function of heart muscle, although some cases have no identified cause.
In obstructive HCM, the thickened heart muscle can interfere with the flow of blood leaving the heart. This obstruction can contribute to symptoms and reduced physical capacity.
Children and adolescents with obstructive HCM may face complications including abnormal heart rhythms, heart failure and atrial fibrillation. Treatment has traditionally included medicines such as beta blockers, calcium channel blockers and disopyramide. Some patients may also require procedures intended to reduce the thickness or impact of the obstructing heart muscle.
The expanded approval provides another potential treatment option for eligible pediatric patients.
FDA Approval Based on the SCOUT-HCM Trial
The expanded indication was supported by results from the Phase 3 SCOUT-HCM clinical trial. The study enrolled 44 adolescents between 12 and under 18 years of age who had symptomatic obstructive HCM.
Participants were randomly assigned to receive either Camzyos or placebo during the initial 28 week controlled treatment period. The trial was double blind and placebo controlled, meaning neither participants nor investigators knew which treatment patients received during that portion of the study.
The primary goal was to evaluate the change in the Valsalva left ventricular outflow tract gradient after 28 weeks. This measurement helps assess the degree of obstruction to blood leaving the heart.
The results showed a significant reduction in the Valsalva LVOT gradient among patients receiving Camzyos compared with those receiving placebo. The least squares mean difference between the groups was 48.0 mmHg, with a 95% confidence interval ranging from 67.7 to 28.3 mmHg. The reported P value was less than 0.0001.
The study also evaluated other measures, including resting and post exercise LVOT gradients and changes in maximal left ventricular wall thickness. The reported data showed reductions in these measures among patients receiving Camzyos.
What Did the Safety Results Show?
Safety is particularly important when considering treatments that affect heart muscle contraction.
In the SCOUT-HCM trial, no patients receiving Camzyos experienced an LVEF below 50%, and no adverse events resulted in treatment discontinuation. The company reported that no new adverse reactions were identified compared with the safety profile previously observed in adults.
Serious adverse events occurred in two patients in the Camzyos group and two patients in the placebo group.
However, the treatment carries important safety warnings. Camzyos can reduce left ventricular ejection fraction, which measures how effectively the heart pumps blood. A significant reduction can result in systolic dysfunction and heart failure.
For this reason, echocardiograms are required before and during treatment. The prescribing information states that treatment should not be initiated when LVEF is below 55%, and treatment should be interrupted if LVEF falls below 50% or if a patient develops heart failure symptoms or worsening clinical status.
Why the Pediatric Approval Matters
The FDA's decision addresses an important treatment gap for children and adolescents with symptomatic obstructive HCM.
Before this expanded indication, pediatric patients had fewer specifically approved treatment options. Although existing therapies could be used to manage symptoms and obstruction, the availability of an FDA approved cardiac myosin inhibitor for eligible pediatric patients represents a significant development.
Camzyos works differently from many traditional treatments. It is a selective and reversible inhibitor of cardiac myosin, a protein involved in heart muscle contraction. By reducing excessive cardiac contractility, the medicine can decrease obstruction in the left ventricular outflow tract.
The goal is not simply to alter a laboratory measurement. Reducing obstruction may help address symptoms and improve functional capacity in appropriate patients.
How the Treatment Is Being Studied
SCOUT-HCM was designed to continue beyond the initial 28 week placebo controlled period. The study includes an additional 28 week active treatment period, followed by an open label long term extension of up to 144 weeks.
This longer follow up is important because researchers need to understand not only the initial response to treatment but also its longer term safety and effectiveness in younger patients.
The trial included adolescents receiving commonly used background therapies. These included beta blockers, calcium channel blockers and disopyramide.
The approval therefore adds to a broader body of evidence surrounding mavacamten, which has previously been studied extensively in adults with symptomatic obstructive HCM.
Important Drug Interaction Considerations
Camzyos also has significant potential interactions with other medicines. The drug is primarily metabolized through the CYP2C19 enzyme pathway and is also affected by CYP3A4 and CYP2C9.
Certain strong CYP2C19 inhibitors and moderate to strong CYP2C19 or CYP3A4 inducers are contraindicated with Camzyos because they can alter drug exposure and potentially increase the risk of heart failure or reduce treatment effectiveness.
Patients and caregivers should therefore provide healthcare professionals with a complete list of prescription medicines, over the counter products and other treatments before starting Camzyos or adding another medication.
Because of the risk of heart failure, Camzyos is also distributed through a restricted Risk Evaluation and Mitigation Strategy program known as the Camzyos REMS. Prescribers, patients and pharmacies must meet specified requirements before the medicine can be supplied.
A New Option for Eligible Young Patients
The expanded FDA indication represents a notable change in the treatment landscape for pediatric obstructive hypertrophic cardiomyopathy. Results from SCOUT-HCM demonstrated that Camzyos reduced measures of left ventricular outflow tract obstruction in adolescents with symptomatic disease.
At the same time, the treatment requires careful monitoring because of its potential effects on heart function. The need for regular echocardiographic assessment, attention to drug interactions and participation in the REMS program highlights the importance of specialist supervision.
For families affected by pediatric oHCM, the availability of an FDA approved cardiac myosin inhibitor offers another option to discuss with a qualified healthcare professional.
Sources
- Bristol Myers Squibb, announcement regarding the FDA expanded indication for Camzyos, September 30, 2026.
- SCOUT-HCM Phase 3 trial information and reported efficacy results.
- Camzyos prescribing information and Important Safety Information.
- Information on obstructive hypertrophic cardiomyopathy and the SCOUT-HCM study.
Disclaimer
This article is provided for general informational and educational purposes only. It is not medical advice, a diagnosis, or a substitute for advice from a qualified healthcare professional. Camzyos is a prescription medicine with important risks, contraindications, monitoring requirements and potential drug interactions. Patients, parents and caregivers should speak with their cardiologist or other qualified healthcare professional before making decisions about treatment.