Mavacamten in Adult Patients With Obstructive Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disorder characterized by left ventricular hypertrophy, with approximately two-thirds of patients presenting with obstructive physiology. Obstructive hypertrophic cardiomyopathy (oHCM) is associated with significant morbidity due to left ventricular outflow tract (LVOT) obstruction. Mavacamten, a first-in-class cardiac myosin inhibitor, directly targets the underlying pathophysiology of oHCM by reducing excessive myosin-actin cross-bridge formation. Although previous randomized clinical trials, such as EXPLORER-CN, have demonstrated its efficacy, real-world data in Chinese populations remain limited. This study is a retrospective cohort study conducted at Fuwai Central China Cardiovascular Hospital. Patients were not assigned to interventions. Instead, they were categorized based on treatments received in routine clinical practice. Eligible adult patients with oHCM who initiated mavacamten therapy were included in the treatment group, while patients receiving standard pharmacological therapy served as the control group. Clinical data were collected from January 2024 to May 2025, with final database lock completed in June 2025. Baseline characteristics, echocardiographic parameters, and laboratory biomarkers were obtained from medical records. The primary endpoint was the change in resting LVOT peak gradient at Week 30 compared with baseline. Secondary endpoints included changes in Valsalva LVOT gradient, NYHA functional class improvement, NT-proBNP, high-sensitivity cardiac troponin I (hs-cTnI), left ventricular ejection fraction (LVEF), and tricuspid annular plane systolic excursion (TAPSE). Safety endpoints included adverse events, serious adverse events, treatment discontinuation, and reduction of LVEF below 50%. This study aims to provide real-world evidence regarding the clinical effectiveness and safety of mavacamten in adult patients with oHCM in China.