Real-World Observations in Patients With Obstructive Hypertrophic Cardiomyopathy Treated With Mavacamten: Evidence of Favorable Disease Modification.

BACKGROUND

Mavacamten is commercially approved for use in symptomatic patients with obstructive hypertrophic cardiomyopathy. This study evaluated its real-world impact on symptoms, echocardiographic changes, and the need for septal reduction therapy in patients with obstructive hypertrophic cardiomyopathy treated at a multihospital referral center.

METHODS

We included 244 patients with obstructive hypertrophic cardiomyopathy (mean age, 64 years; 57% women, 21% with atrial fibrillation, 51% New York Heart Association class III, 82% on β-blockers) treated with mavacamten for ≥3 months (171 for ≥12 months). Serial clinical and echocardiographic assessments were performed.

RESULTS

New York Heart Association class distribution improved over time: at 3 months 21% class I, 61% class II, and 18% class III; at 12 months 36% class I, 57% class II, and 8% class III. After a mean of 1.02 years, significant improvements were observed in resting and post-Valsalva left ventricular outflow tract gradients (-31±33 and -57±46 mm Hg), interventricular septal thickness (-1.7±4 mm), left ventricular mass index (-9.5±32 g/m2), left atrial volume index (-12±13 mL/m2), E/e' (-5.5±6.4), left ventricular global longitudinal strain (1.04%±3.1%), and various left atrial and right ventricular strain measures (all P<0.05). Temporary interruption occurred in 8 patients (3.2%), and 3 (1.2%) discontinued mavacamten permanently. There were 2 noncardiac deaths, 7 heart failure admissions, 14 cases of new-onset atrial fibrillation, and 1 patient required septal reduction therapy. At the last visit, most patients were on 5 mg (49%) or 10 mg (26%) mavacamten.

CONCLUSIONS

In this real-world cohort, mavacamten treatment was associated with sustained symptomatic and echocardiographic improvements, suggesting a favorable disease-modifying impact with minimal need for septal reduction therapy.