SCOUT-HCM: Mavacamten in Adolescents With Symptomatic Obstructive Hypertrophic Cardiomyopathy

Dr. Rossano:
Hello. From ACC 2026 here in New Orleans, I'm Dr. Joe Rossano, and I'd like to share some key findings from the SCOUT-HCM trial, which evaluated mavacamten in adolescents with symptomatic obstructive hypertrophic cardiomyopathy. These results represent an important step towards understanding how targeted therapies may help address disease burden in younger patients with obstructive hypertrophic cardiomyopathy.

We performed a randomized controlled trial of mavacamten compared with placebo in 44 adolescents with significant obstruction within hypertrophic cardiomyopathy. The primary endpoint was a reduction in Valsalva left ventricular outflow tract gradient measured at 28 weeks. We also looked at a number of secondary endpoints, including peak left ventricular outflow tract obstruction, measures of diastolic function, degree of mitral regurgitation, biomarkers of myocardial stress and myocardial injury, and NYHA functional class.

We were pleased to see that SCOUT-HCM met its primary endpoint, and mavacamten was associated with a clinically meaningful and statistically significant improvement in Valsalva LVOT gradient. We also saw improvements in most of our key secondary endpoints, including peak LVOT gradients, measures of diastolic function, improvements in natriuretic peptide levels, troponin levels, improvements in the degree of mitral regurgitation, and improvements in NYHA functional class.

This is the first time that we have seen a targeted therapy be used in children, and the results from this prospective randomized trial, I think, have the potential to fundamentally change how we approach this disease in treating younger patients with HCM.

We are currently performing a long-term follow-up study, and it will be very important for us to see if these results that we saw at 28 weeks are sustained in the long term.

From ACC 2026, I'm Dr. Joe Rossano, and thank you for watching.