Mavacamten in Adolescents with Obstructive Hypertrophic Cardiomyopathy

Area of Science:

• Cardiology
• Pharmacology
• Clinical Trials

Background:

• Limited approved pharmacologic therapies exist for pediatric hypertrophic cardiomyopathy (HCM).
• Surgical intervention is sometimes necessary for HCM patients with left ventricular outflow tract obstruction.
• Mavacamten, a cardiac myosin inhibitor approved for adults, requires evaluation in adolescents.

Purpose of the Study:

• To evaluate the efficacy and safety of mavacamten in adolescent patients with obstructive hypertrophic cardiomyopathy.
• To assess the change in left ventricular outflow tract pressure gradient in response to mavacamten treatment.

Main Methods:

• Phase 3, double-blind, randomized, placebo-controlled trial.
• Involved symptomatic adolescents (12 to <18 years) with New York Heart Association class II or III obstructive HCM.
• Primary endpoint: change in Valsalva maneuver-provoked left ventricular outflow tract pressure gradient at 28 weeks.

Main Results:

• 44 adolescents randomized; 23 received mavacamten, 21 received placebo.
• Mavacamten group showed a mean reduction of -48.5 mm Hg in the gradient vs. -0.5 mm Hg in placebo (P<0.001).
• Adverse event incidence was similar; no deaths occurred, and no patient had ejection fraction <50%.

Conclusions:

• Mavacamten demonstrated a significantly greater reduction in left ventricular outflow tract obstruction compared to placebo in adolescents over 28 weeks.
• The study suggests mavacamten is a potential therapeutic option for pediatric obstructive HCM.
• Further research and long-term safety data are warranted.