For the roughly one in 500 adults living with hypertrophic cardiomyopathy, the treatment landscape has just gained a meaningful new option — one that targets the molecular root of abnormal heart muscle contraction rather than simply managing downstream symptoms. That mechanistic precision is what makes this regulatory milestone worth examining closely.
Aficamten (MYQORZO™), developed by Cytokinetics, is a selective small-molecule inhibitor of cardiac myosin — the motor protein whose hypercontractility drives the obstruction and symptoms characteristic of obstructive HCM (oHCM). Its approval in the United States and China in December 2025, followed by European Union clearance in February 2026, rests on the phase III SEQUOIA-HCM trial: a randomized, double-blind, placebo-controlled study demonstrating statistically significant improvements in functional capacity and symptom burden in adults with symptomatic oHCM. The drug is now also under phase III evaluation for non-obstructive HCM (nHCM), a harder-to-treat variant with fewer established pharmacological options.
Aficamten enters a field already transformed by mavacamten (Camzyos), the first approved cardiac myosin inhibitor, which received FDA clearance in 2022. The emergence of a second agent in this class matters for several reasons. Clinically, it offers an alternative for patients who may not tolerate or respond optimally to mavacamten. Scientifically, independent validation of the myosin-inhibition mechanism in HCM strengthens confidence in the target itself, shifting it from novel hypothesis to replicated therapeutic strategy. Both drugs carry cardiac safety considerations — myosin inhibition can reduce ejection fraction if not carefully monitored — so the risk-benefit calculus remains patient-specific. Aficamten's distinct pharmacokinetic profile may translate into a different drug-interaction landscape than mavacamten, a clinically relevant distinction given that HCM patients often carry concurrent cardiovascular medications. This is an incrementally significant, confirmatory advance rather than a paradigm shift, but for a historically under-treated condition, confirmed mechanistic options represent genuine progress.