Effects of vutrisiran on cardiac structure and function in patients with transthyretin amyloidosis with cardiomyopathy: secondary outcomes of the HELIOS-B trial.

In the HELIOS-B randomized clinical trial, the RNA interference therapeutic agent vutrisiran reduced the risk of all-cause mortality and recurrent cardiovascular events among patients with transthyretin amyloidosis with cardiomyopathy (ATTR-CM). In this secondary analysis of HELIOS-B, we evaluated vutrisiran's effects on echocardiographic measures of cardiac structure and function in patients with ATTR-CM receiving vutrisiran or placebo (n = 654, 93% men). At 30 months after treatment, as compared to the placebo group, vutrisiran treatment attenuated increases in mean left ventricular (LV) wall thickness (least squares mean difference: -0.4 mm; 95% confidence interval (CI): -0.8, 0.0; P = 0.03) and LV mass index (-10.6 g m; 95% CI: -18.0, -3.3; P < 0.01). Vutrisiran treatment also attenuated declines in LV ejection fraction (2.0%; 95% CI: 0.3, 3.7; P = 0.02), absolute global longitudinal strain (1.2%; 95% CI: 0.7, 1.7; P < 0.01) and LV stroke volume (4.1 ml; 95% CI: 1.7, 6.4; P < 0.01), and decreased both the average ratio of early diastolic transmitral flow velocity to early diastolic mitral annular tissue velocity (-2.0; 95% CI: -2.9, -1.2; P < 0.01) and the early to late diastolic transmitral flow velocities ratio (-0.3; 95% CI: -0.6, -0.0; P = 0.04), as compared to placebo. Consistent with its clinical benefits, these echocardiographic findings indicate favorable effects of vutrisiran on cardiac structure and function in patients with ATTR-CM. ClinicalTrials.gov registration: NCT04153149 .