Breakthrough therapy designation for Mavacamten, new medication for HOCM

Breakthrough therapy designation for Mavacamten, new medication for HOCM

HOCM stands for hypertrophic obstructive cardiomyopathy. It is a genetic disease of the heart muscle in which the heart muscle becomes unduly thickened and causes obstruction to outflow of blood from the left ventricle. Left ventricle is the lower left chamber of the heart which pumps blood to the whole body. So far HOCM was being treated with medications like beta blockers, some types of calcium channel blockers and disopyramide. These drugs reduce the force of contraction of the left ventricle. Mavacamten is a first-in-class drug which inhibits cardiac myosin, a protein required for heart muscle contraction.

United States Food and Drug Administration (USFDA) has approved Mavacamten for adults with symptomatic HOCM to improve exercise capacity and symptoms. The approval is for those in New York Heart Association functional class II or III, which would mean those with mild to moderate symptoms. That also means it is not meant for the most symptomatic persons in class IV and those without symptoms in class I. The medication has been designated as breakthrough therapy for the specified treatment.

An important safety information mentioned by USFDA is the possibility of heart failure, which is more likely in those with intercurrent infection or heart rhythm abnormalities like atrial fibrillation with fast ventricular rate. Atrial fibrillation is a fast irregular rhythm originating from the upper chambers of the heart and can worsen the functional status in HOCM. They suggested monitoring with echocardiogram to assess heart function. Echocardiogram is ultrasound study of the heart.

Possibility of drug interactions with certain prescription and over the counter drugs which interfere with the metabolism of mavacamten have also been highlighted. Due to the risk of heart failure, mavacamten is available only through a Risk Evaluation and Mitigation Strategy (REMS) to ensure safe use by lowering the risk of heart failure. Use along with certain medications is to be avoided and close monitoring has been recommended in case of some medications. Most important monitoring is serial assessment of the pumping function of the heart, typically by echocardiography.