Real-World Implementation and Clinical Outcomes of Mavacamten in an Underserved Urban Cohort With Obstructive Hypertrophic Cardiomyopathy

Background Real-world data regarding mavacamten use in underserved and racially diverse populations remain limited, particularly for long-term therapy implementation. Structural barriers such as financial instability, fragmented healthcare access, and challenges adhering to REMS-related monitoring requirements may affect longitudinal therapy implementation. Methods We performed a retrospective observational study of consecutive patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) evaluated for mavacamten therapy at a tertiary HCM center in Bronx, NY, between 6/2022-10/2025. Patients were followed for up to 48 weeks after treatment initiation. Clinical characteristics, treatment interruptions, adverse events, echocardiographic and functional outcomes, and implementation barriers were assessed descriptively. Results Seventy-two patients with symptomatic oHCM were evaluated for mavacamten; sixty-seven initiated treatment. Mean age was 66.9{+/-}15.3 years, 72% were female, and 61% identified as Black or Hispanic. Median resting left ventricular outflow tract (LVOT) gradient decreased from 51mmHg (IQR30-88) at baseline to 7mmHg (IQR5-10) at 48 weeks. Median Valsalva LVOT gradient decreased from 74mmHg (IQR50-104) to 20mmHg (IQR10-29). At final follow-up, 80% of patients improved by [≥]1 NYHA functional class. LVEF declined below 50% in five patients and recovered in all cases. Approximately one-quarter experienced treatment interruption or discontinuation, nearly half related to insurance instability, non-adherence, and REMS-related monitoring barriers. Conclusions Mavacamten demonstrated efficacy and safety outcomes comparable to those reported in clinical trials and prior registries in this predominantly underserved minority urban cohort. However, structural and healthcare-access barriers substantially affected long-term treatment implementation. These findings highlight the need to address healthcare-system barriers to ensure equitable implementation of contemporary HCM therapies.