Hypertrophic cardiomyopathy (HCM) is a common inherited disease characterized by unusual thickening of the heart muscles which makes it difficult for the heart to pump the blood.
Mavacamten is the first new medication developed to treat the thickening of the heart muscle and its function. The study was published in Circulation.
The current treatment options available only treat the symptoms and not the underlying cause that is the thickening of the heart muscle resulting in stiffness and cardiac structural abnormalities. They are also not able to prevent development of heart failure and death.
Cause of HCM
Motor proteins mainly myosin, uses energy which results in contraction of the heart muscle and pumping of the blood. In HCM, the interactions between the motor proteins increases to a great extent which leads to vigorous squeezing of the heart muscle resulting in stiffness.
Mavacamten belongs to the class of drug cardiac myosin inhibitors, is a medication specifically designed for HCM and is currently being studied in clinical trials. The medication blocks the interaction of myosin with other motor proteins which allows the heart muscles to relax and contract normally. It also reduces the obstruction to blood flow within the heart which may result with this disease.
Findings of the study
Saberi said, "It's the first class of medications that actually targets the underlying pathophysiology of HCM."
On analysis it was seen that the mass of the heart was reduced in patients taking the drug. There was also significant improvement to obstruction of blood flow within the heart. The patients also showed improvement in the exercise capacity and felt better after taking the drug for 30 weeks.
A substudy was performed to understand the reason why the patients felt better using cardiac imaging. The imaging was done after 30 weeks of treatment and encouraging results were observed. Saberi said, "Cardiac MRI has such incredible visual and spatial resolution that you can accurately examine the heart's mass, volume, ejection fraction, or how well the blood is pumping, and fibrosis, which is the scar burden in the heart muscle. It's also encouraging that we don't see a worsening in fibrosis along with the normalization in ejection fraction." Patients with HCM had high ejection fraction which reduced with treatment.
More than 500 people are affected by HCM hence more effective treatment options are needed.
The clinical trials for Mavacamten are moving ahead and its use is also being evaluated in non-obstructive HCM. The medication is only available in the clinical trial settings currently.