The New England Journal of MedicineAficamten for Symptomatic Obstructive Hypertrophic Cardiomyopathy

Aficamten shows promise in enhancing exercise capacity and reducing symptoms in obstructive hypertrophic cardiomyopathy, potentially affecting treatment approaches for related cardiac conditions.

A recent phase 3, double-blind trial has evaluated the efficacy of aficamten, an oral selective cardiac myosin inhibitor, in treating symptomatic obstructive hypertrophic cardiomyopathy (HCM). This study focused on improving exercise capacity and reducing symptoms by targeting left ventricular outflow tract obstruction, a common issue in HCM patients.

Study Design:

• Participants: 282 adults with symptomatic obstructive HCM
• Randomization: 142 patients received aficamten, 140 received placebo
• Age and Gender: Mean age of 59.1 years; 59.2% male
• Baseline Measurements:
  • Mean resting left ventricular outflow tract gradient: 55.1 mm Hg
  • Mean left ventricular ejection fraction: 74.8%
• Intervention: Aficamten starting dose of 5 mg, adjustable up to 20 mg, over 24 weeks
• Primary Endpoint: Change in peak oxygen uptake from baseline to week 24
• Secondary Endpoints: Assessed at weeks 12 and 24, including changes in KCCQ-CSS, NYHA functional class, Valsalva maneuver pressure gradient, and total workload.

Key Findings:

• Primary Endpoint: Significant improvement in peak oxygen uptake with aficamten (mean change of 1.8 ml/kg/min) versus placebo (0.0 ml/kg/min); between-group difference of 1.7 ml/kg/min (P<0.001).
• Secondary Endpoints: Significant improvements across all 10 measures with aficamten compared to placebo at both 12 and 24 weeks.
• Adverse Events: Similar incidence between aficamten and placebo groups.

HCN Medical Memo
Aficamten has demonstrated substantial benefits in managing symptomatic obstructive hypertrophic cardiomyopathy by improving peak oxygen uptake and reducing symptom severity. This trial suggests that aficamten could become a valuable addition to current treatment strategies, offering improved patient outcomes through targeted reduction of cardiac hypercontractility.

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