What are the pros and cons of taking Mavakat/Mefanto in patients with cardiac hypertrophy?

As the first oral small molecule inhibitor targeting cardiac myosin, mavacamten brings a new direction to the treatment of obstructive hypertrophic cardiomyopathy (oHCM). Its main function is to reduce the excessive interaction of cardiac myosin, reduce the pressure of the left ventricular ejection tract (LVOT), and reduce myocardial oxygen consumption, thereby improving exercise tolerance and cardiac comfort. However, for patients with cardiac hypertrophy, the use of Mavacartide has both obvious clinical benefits and risks that require special attention, so the balance of benefits and harms is particularly critical for long-term treatment.

From the advantage point of view, the biggest feature of Mavaceta is that it targets the pathophysiological root of HCM - excessive activation of cardiac myosin. Traditional treatments mostly rely on β-blockers or calcium channel blockers to achieve indirect relief by adjusting heart rate or improving diastole, while Mavaceta directly regulates myocardial contractile proteins to achieve a sustained and stable reduction in the mechanical burden of the myocardium. This mechanistic advantage has shown positive results in improving the obstruction pressure difference, alleviating dyspnea and improving the quality of life in overseas studies. For patients who are prone to long-term chest tightness, fatigue, or palpitations after exercise, this drug can bring daily physical fitness levels closer to normal, and can also reduce recurring symptom fluctuations caused by obstruction.

However, the risks of using mavacate are closely related to its mechanism of action. Although inhibiting myosin can reduce excessive contraction, it may also lead to a decrease in contractile function. The most typical risk is a decrease in left ventricular ejection fraction (LVEF), which is the most important monitoring indicator among myosin inhibitors. Especially patients with borderline ejection fraction or myocardial fibrosis need to be closely evaluated during use to avoid symptoms related to heart failure. In addition, Mavaceta needs to be used under a specific dose escalation strategy. Each patient's metabolic rate, genotype and myocardial structure will affect the drug's blood concentration, so individualized adjustment is particularly important.

Reference materials:https://bnf.nice.org.uk/drugs/mavacamten/