Overview
- The SCOUT-HCM randomized trial, presented Sunday at the ACC meeting and published in NEJM, tested mavacamten in 44 adolescents ages 12 to 17 with symptomatic obstructive hypertrophic cardiomyopathy.
- Compared with placebo, mavacamten reduced the Valsalva LVOT gradient by an average of 48.5 mm Hg versus 0.5 mm Hg, a between-group difference of 48 mm Hg that brought many patients below the guideline threshold for obstruction.
- Short-term safety matched placebo with no deaths, no drops in left ventricular ejection fraction below 50%, and no cases of atrial fibrillation or symptomatic heart failure over 28 weeks.
- Secondary measures improved with treatment including resting and post-exercise obstruction, heart wall thickness, diastolic function, symptoms, and blood markers of heart injury, which together suggest possible favorable remodeling that could delay surgery for some teens.
- Investigators flagged limits such as the small, mostly White sample and the 28-week duration, disclosed Bristol Myers Squibb funding and consultancy ties, and noted an extension and broader pediatric studies are underway to confirm durability and safety.