Aficamten-MYQORZO side effects and precautions

Aficamten (aficamten)-MYQORZO is a prescription drug for the treatment of adult symptomatic obstructive hypertrophic cardiomyopathy. The only adverse reaction identified in clinical studies is hypertension, but it has a clear risk warning of heart failure. During medication, various precautions must be strictly followed, and monitoring and dose management must be done.

This drug carries a box warning about the risk of heart failure. The core risk is reducing left ventricular ejection fraction (LVEF), inhibiting myocardial contractility and causing systolic dysfunction, ultimately leading to heart failure. In particular, patients with serious infections, new onset or uncontrolled arrhythmias such as atrial fibrillation are at higher risk, and those with asymptomatic LVEF reduction, underlying diseases, and arrhythmias require intensive monitoring. The patient's clinical status and LVEF must be regularly assessed before medication and during treatment, and the dosage must be adjusted. If signs of heart failure such as aggravation of arrhythmia, dyspnea, chest pain, lower limb edema, or elevated NT-proBNP occur, cardiac function must be checked immediately, and initial medication is prohibited for those with LVEF <55%.

Due to the risk of heart failure, the drug is only available through the MYQORZO REMS restricted program, which requires prescribers and pharmacies to complete certified registration, patients need to participate in the program and cooperate with continuous monitoring, and wholesalers can only distribute to certified pharmacies.

In addition, the metabolism of this drug is easily affected by cytochrome P450 enzymes. Combined use with strong CYP2C9 inhibitors such as fluconazole and multi-pathway P450 inhibitors, or discontinuation of moderately strong CYP3A inducers will increase the blood concentration and increase the risk of heart failure; combined use with rifampicin and P450 inducers will reduce the blood concentration, resulting in loss of drug efficacy. LVEF needs to be rechecked and the dosage adjusted 2-8 weeks after the combined use of related drugs. Patients must proactively inform their doctors of all combined drugs to avoid interactions.

Reference materials:https://en.wikipedia.org/wiki/Aficamten