Analysis of the core points of the instruction manual of Mavakatai/Mefanto

Mavacamten is an innovative cardiac myosin inhibitor for the treatment of obstructive hypertrophic cardiomyopathy (HCM) in adults. This drug improves the coordination of cardiac relaxation and contraction, thereby relieving patients' symptoms such as dyspnea, palpitations, and fatigue after activity. It is one of the important breakthroughs in the current precision treatment of cardiomyopathy.

1. Indications

Mavaceta is mainly used for patients with New York Heart Association (NYHA) grade II to III obstructive hypertrophic cardiomyopathy. Its core goal is to reduce the left ventricular outflow tract pressure gradient (LVOT), improve cardiac function and exercise tolerance, thereby improving quality of life. This drug is not an ordinary cardiac assist drug, but a molecular-level intervention targeting the root cause of pathological myocardial hypercontraction.

2. Usage and dosage

1. Initiation and monitoring: Before treatment, it should be confirmed that female patients are not pregnant and reliable contraceptive measures should be taken. For patients whose left ventricular ejection fraction (LVEF) is less than 55%, it is not recommended to start or increase the dose.

2. Recommended dose: The starting dose is 5 mg taken orally once a day. It can be taken with food or on an empty stomach. Depending on individual response, the dose may be adjusted between 2.5 mg and 15 mg. Capsules should be swallowed whole and should not be opened or chewed. It usually takes several weeks to reach steady-state concentrations, and metabolic differences and drug interactions may affect plasma levels.

3. Principle of dose adjustment: During treatment, LVEF and Valsalva LVOT gradient should be monitored regularly to ensure LVEF ≥ 50% to avoid the risk of heart failure. When the LVEF drops below 50%, the medication needs to be suspended immediately, and whether to restart it will be decided based on the recovery situation. For those who paused at the 2.5 mg dose, they can choose to restart the drug at the same dose or permanently discontinue the drug.

4. Drug interactions: When using weakCYP2C19 or moderate CYP3A4 inhibitors, the dose of Marvaceta needs to be reduced by one level. For example, 15mg is reduced to 10mg, 10mg is reduced to 5mg, etc. If you are already at the lowest dose of 2.5 mg, you should avoid combining such inhibitors to prevent overdose.

3. Adverse reactions

Clinical studies show that common side effects include dizziness, shortness of breath, decreased cardiac systolic function, and syncope. These symptoms are mostly related to the inhibitory effect of drugs on myocardial contractility. Once obvious discomfort occurs, LVEF should be monitored promptly and the dose should be adjusted. Most reactions are mild to moderate and can be relieved after stopping the drug or reducing the dose.

4. Taboos and Precautions

Mavaceta is strictly prohibited to be used simultaneously with moderate to severeCYP2C19 inhibitors, severe CYP3A4 inhibitors or inducers, otherwise it may cause abnormal increase or decrease in blood concentration, affecting efficacy and safety. The patient's concomitant medication history should be fully evaluated before use, and combined use with strong metabolism-regulating drugs should be avoided.

5. Pharmacological mechanism

Mavacate reduces the excessive cross-linking between myosin and actin through allosteric and reversible inhibition of cardiac myosin. This mechanism puts the myocardium in an "energy-saving and recoverable" super-relaxed state, fundamentally reducing myocardial contractile load and reducing LVOT obstruction, thereby improving diastolic filling and cardiac output. This molecular-level regulation method is different from traditional beta-blockers or calcium channel blockers, and is more targeted and controllable.

6. Storage and specifications

Mavakate is an immediate-release hard gelatin capsule, available in specifications:2.5mg, 5mg, 10mg and 15mg. It should be stored in an environment between 20°C and 25°C, and can fluctuate between 15°C and 30°C for short periods of time. Avoid moisture and direct sunlight.

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