Wang, Quing

Introduction: In the randomized VALOR-HCM study of symptomatic patients with obstructive hypertrophic cardiomyopathy (oHCM), mavacamten reduced the need for septal reduction therapy at 16 weeks. The current sub-study sought to assess the impact of mavacamten on systolic anterior motion (SAM) of the mitral valve and associated mitral regurgitation (MR). Methods: Patients on maximally-tolerated medical therapy referred for septal reduction therapy were randomized 1:1 to mavacamten or placebo. Echocardiographic assessment was performed by an independent, blinded core laboratory. SAM was assessed as none, mild (anterior leaflet >/= 1 cm from the septum), moderate (anterior leaflets <1cm from the septum), and severe (anterior leaflet in contact with septum). MR was assessed according to ASE guidelines. Results: Among 112 enrolled patients, 23.2% (n=27) had at least moderate (2+) MR. Most (92.9%, n=104) had at least moderate resting SAM, of whom 55.4% (n = 62) had severe SAM. At 16 weeks, 53.7% of patients treated with mavacamten had at least one level improvement in resting SAM compared to 21.6% of patients treated with placebo ( p = 0.001), and 35.2% had at least a two level improvement in SAM compared with 11.8% of placebo patients ( p = 0.007)(Figure 1A). Similarly, patients treated with mavacamten had an improvement of -36.0 + 28.8 mmHg in resting left ventricular outflow tract gradient at week 16 compared to -1.5 + 26.5 mmHg with placebo (<0.001). At week 16, 48.1% of patients treated with mavacamten had at least a one grade improvement in MR, and 23.1% had at least a two grade improvement compared to 12.2% and 6.1% of patients treated with placebo ( p <0.001 and 0.025, respectively)(Figure 1B). Conclusions: In highly symptomatic patients with oHCM, treatment with mavacamten reduced resting SAM with an improvement in associated MR.

Introduction: In the randomized VALOR-HCM study of symptomatic patients with obstructive hypertrophic cardiomyopathy (oHCM), mavacamten reduced the need for septal reduction therapy at 16 weeks. Because mavacamten is a cardiac myosin inhibitor that may improve ventricular compliance, this sub-study hypothesized that mavacamten would favorably impact diastolic function. Methods: Symptomatic patients on maximally-tolerated medical therapy referred for septal reduction therapy were randomized 1:1 to mavacamten or placebo. Echocardiographic assessment was performed by an independent, blinded core laboratory. Diastolic grade was determined according to ASE guidelines. Between-group comparisons were made from baseline to week 16. Results: Among 112 enrolled patients, baseline left atrial volume index (LAVi) was similar (Table). At 16 weeks, mavacamten treatment resulted in a significant reduction in LAVi (-5.2 vs -0.5 with placebo, p = .003). Similarly, although lateral E/e’ and septal E/e’ were comparable at baseline, patients treated with mavacamten demonstrated a significant reduction at week 16 (lateral E/e’: -3.5 vs 0.7, p <0.001; septal E/e’: -3.3 vs 0.7, p < 0.001)(Table). Patients treated with mavacamten were also more likely to improve their diastolic dysfunction grade (31.4% vs 12.8%, p = 0.032) (Figure). Conclusions: After only 16 weeks of therapy, in a highly symptomatic oHCM population with echocardiographic-guided drug titration, mavacamten improved measures of diastolic function.