Mavacamten Shows Promise for Adolescents with Hypertrophic Cardiomyopathy
Mavacamten significantly reduces heart obstruction in adolescents with hypertrophic cardiomyopathy, with patients experiencing a 48.5 mm Hg drop in blockage compared to minimal change in placebo groups. The drug also lowered blood markers indicating heart damage and showed promise in slowing disease progression. Separate real-world data confirms mavacamten's effectiveness as monotherapy across diverse patient populations.
Researchers have reported that adolescents with hypertrophic cardiomyopathy who took mavacamten experienced reduced obstruction, allowing blood to flow more easily from the heart. The research, presented at the American College of Cardiology's Annual Scientific Session in New Orleans, was also published in the New England Journal of Medicine. This is the first study to assess the drug in adolescents, who typically have more severe disease than adults.
Hypertrophic cardiomyopathy is the most common inherited heart disease and is characterized by abnormal thickening and stiffness of the heart muscle, which can obstruct blood flow. The condition can cause chest pain, dizziness, shortness of breath, and swelling, and can progress to heart failure, dangerous arrhythmias or sudden cardiac death. Mavacamten, a medication that reduces myosin activity to improve cardiac function, is approved for adults.
In the study, global trial sites enrolled 44 teens (ages 12 to <18) with symptomatic obstructive HCM. Of those, 23 participants randomly received mavacamten and 21 received a placebo for 28 weeks. The trial was double-blind, meaning that neither families nor doctors knew who got the drug.
After 28 weeks, patients taking mavacamten experienced a significant drop in the blockage leaving the heart (about 48.5 mm Hg) compared with almost no change (0.5 mm Hg) in the placebo group. Side effects were similar in both groups, and all patients met a key safety threshold. Overall, mavacamten greatly reduced the obstruction in adolescents with HCM and appeared safe in this study.
Additionally, blood markers that indicate heart damage fell in patients taking mavacamten but rose in those on placebo. That pattern suggests mavacamten may do more than ease symptoms; it could slow disease progression and even reverse some damage to the heart.
A separate international study published in Circulation: Genomic and Precision Medicine shows that mavacamten used as a standalone therapy, without beta-blockers or calcium-channel blockers, significantly improves symptoms and cardiac obstruction in people with obstructive hypertrophic cardiomyopathy. The study draws on real-world clinical data from 278 patients across five countries.
The improvements observed are consistent across multiple health systems and patient populations, including groups historically underrepresented in clinical trials. Across the nine-month follow-up period, 60 percent of patients treated with mavacamten monotherapy improved by at least one New York Heart Association class, and outflow tract gradients fell by 35-59 mmHg on average, bringing most patients below guideline thresholds for obstruction.
This study was supported by Bristol Myers Squibb. Mavacamten is developed to specifically counteract excessive cardiac muscle contraction and represents a new class of precision therapeutics.