Imagine struggling to catch your breath and feeling chest pains just from climbing a flight of stairs.
For many living with the genetic heart condition obstructive hypertrophic cardiomyopathy (HCM), this is a harsh reality. But a newly tested drug offers hope to those weighed down by the disease.
Patients Exercise Longer, Feel Better
HCM is when the heart muscle thickens abnormally, impeding the heart’s ability to pump blood efficiently. In obstructive HCM, this thickened muscle obstructs blood flow from the heart.“In a very profound way, it was one of the highest improvements in terms of exercise capacity that has ever been seen in any study in heart diseases,” said Dr. Maron, who is also the director of the Hypertrophic Cardiomyopathy Center at Lahey Hospital and Medical Center in Burlington, Massachusetts.
Of the 282 adult participants in the trial, 142 received the experimental drug, while the other 140 took a placebo. The scientists measured the participants’ oxygen levels as they exercised on treadmills or stationary bikes.
At 24 weeks, those taking aficamten increased their maximum oxygen uptake—a measure of cardiovascular fitness—by 1.8 milliliters per kilogram per minute (ml/kg/min) more than the control group. A 1-ml/kg/min increase is considered a clinically significant difference.
“In parallel with that, the patients also felt better,” Dr. Maron added.
Hope for a Genetic Heart Disease
HCM affects around one in 500 people worldwide. The obstructive form, seen in 70 percent of cases, is a leading cause of sudden death in young, otherwise healthy athletes. Often genetically inherited, HCM can cause shortness of breath, chest pain, and abnormal heart rhythms.This largest-ever obstructive HCM trial involved participants from 101 sites across 14 countries. Randomized double-blind, all had reduced exercise capacity due to symptomatic obstructive HCM, with baseline peak oxygen uptake of just 18 to 19 ml/kg/min, severely limiting physical activity.
Aficamten provided patients with a significant, safe opportunity to exercise, with fewer serious adverse events than with the placebo. Unlike the first approved cardiac myosin inhibitor, mavacamten (Camzyos), which risks heart failure in some patients and requires intense monitoring, aficamten has a shorter half-life and broader therapeutic window, allowing for easier dose adjustments.
