US approval brings targeted heart treatment to children

Children with a serious condition that obstructs blood flow from the heart now have a newly approved treatment option in the United States. On September 30, 2026, the Food and Drug Administration expanded approval of Camzyos, also called mavacamten, to children weighing at least 30 kilograms (66 pounds) who have symptomatic obstructive hypertrophic cardiomyopathy.

The condition involves an abnormally thickened heart muscle and can make daily activities difficult. Camzyos targets excessive heart-muscle contraction to reduce the obstruction. Made by Bristol Myers Squibb, it is the first FDA-approved therapy specifically for this condition in children. Its initial approval for adults came in 2022.

The pediatric approval rests on SCOUT-HCM, an international trial involving 44 adolescents aged 12 to 17. After 28 weeks, those receiving Camzyos had a significantly greater reduction in a pressure measurement used to assess obstruction than those receiving placebo. Serious adverse events occurred in two patients in each group, and no adverse events led participants to stop treatment.

The findings offer encouragement, but the study was small and long-term outcomes in children are not yet known. Camzyos can cause heart failure, so heart ultrasound scans are required before and during treatment. In the US, it is available only through a restricted safety program.