Abstract 4362395: Efficacy of Mavacamten Combined with Standard Therapy in Hypertrophic Obstructive Cardiomyopathy: A Retrospective Cohort Study

Background: Hypertrophic obstructive cardiomyopathy (HOCM) is usually treated with standard therapy: beta-blockers (BBs) and/or non-dihydropyridine calcium channel blockers (CCBs). Mavacamten, a selective cardiac myosin inhibitor, has shown efficacy in improving functional status and reducing obstruction. Research Question: Does the addition of Mavacamten to standard therapy with calcium channel blockers and beta-blockers improve functional status and reduce mortality in patients with HOCM? Aims: The aim of this study was to assess the efficacy of Mavacamten plus standard therapy versus standard therapy alone in improving functional status and reducing mortality in HOCM patients. Methods: This retrospective cohort analysis used the TriNetX database to compare adult patients who were prescribed mavacamten plus standard therapy (CCBs and/or BBs) after being diagnosed with HOCM (intervention group), while the control group included patients treated with standard therapy alone. A 1:1 propensity score-matched (PSM) analysis controlled for 76 baseline demographic and clinical characteristics. Outcomes were analyzed over a 365-day period post-index date and were assessed through the odds ratio (OR) and 95% confidence interval (CI) Results: The intervention group included 405 patients, while the control group included 15,871. After PSM, 381 patients were included in each group; 59.3% and 62.2% were female, respectively. The mean age was 62.6 (SD ± 14.4) and 63.9 (SD ± 16) years, respectively. The addition of mavacamten was associated with a significant reduction in all-cause hospitalizations (OR 0.583, CI 0.433-0.787, P < .0001), emergency hospitalizations (OR 0.669, CI 0.467-0.961, P = 0.029), cardiac-related hemodynamic instability (OR 0.433, CI 0.269-0.696, P < .0001), and acute myocardial infarction (OR 0.266, CI 0.130-0.546, P < .0001), and enhanced left ventricular ejection fraction (LVEF > 50%) (OR 2.680, CI 1.703-4.217, P < .0001). Other analyzed outcomes, such as mortality, new-onset systolic or diastolic heart failure, were comparable between the two groups Conclusion: Mavacamten plus CCBs/BBs reduced hospitalizations, improved cardiac biomarkers, and showed favorable trends in mortality and heart failure, supporting its use in clinical practice and the need for long-term studies.