Efficacy of Acoramidis on All-Cause Mortality and Cardiovascular Hospitalization in Transthyretin Amyloid Cardiomyopathy

Background: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed chronic disease associated with progressive heart failure that results in impaired quality of life, repeated hospitalizations, and premature death. Acoramidis is a selective, oral transthyretin stabilizer recently approved by the U.S. Food and Drug Administration for the treatment of ATTR-CM. In a phase 3, randomized, double-blind study (ATTRibute-CM [Efficacy and Safety of AG10 in Subjects With Transthyretin Amyloid Cardiomyopathy]), acoramidis was well tolerated and showed clinical efficacy in improving the primary endpoint, a hierarchical combination of all-cause mortality (ACM), cardiovascular-related hospitalization (CVH), N-terminal pro-B-type natriuretic peptide level, and 6-minute walk distance. Objectives: The goal of this study was to characterize the efficacy of acoramidis on ACM and CVH. Methods: In ATTRibute-CM, participants with ATTR-CM were randomized 2:1 to receive acoramidis hydrochloride (800 mg twice daily) or placebo for 30 months. Efficacy analyses were conducted in the modified intention-to-treat population (participants with a baseline estimated glomerular filtration rate ≥30 mL/min/1.73 m2). CVH and the composite of ACM or first CVH were plotted by using Kaplan-Meier curves and summarized with a stratified Cox proportional hazards model. The annualized frequency of CVH was analyzed by using a negative binomial regression model. Subgroup analyses were conducted for the composite of ACM or first CVH. Results: Of the 632 participants randomized to treatment, 611 (97%) were included in efficacy analyses (acoramidis, n = 409; placebo, n = 202). Compared with placebo, acoramidis reduced the occurrence of the composite of ACM or first CVH (acoramidis, 35.9%; placebo, 50.5%; HR: 0.64; 95% CI: 0.50-0.83; P = 0.0008) and of first CVH (acoramidis, 26.7%; placebo, 42.6%; HR: 0.60; 95% CI: 0.45-0.80; P = 0.0005), with Kaplan-Meier curves separating at month 3 and continuing to diverge through month 30. Annualized frequency of CVH was reduced with acoramidis compared with placebo (acoramidis, 0.22; placebo, 0.45; relative risk ratio: 50%; 95% CI: 0.36-0.70; P < 0.0001). The efficacy of acoramidis on the composite of ACM or first CVH was consistent across subgroups. Acoramidis was well tolerated, with no safety signals of potential clinical concern identified. Conclusions: In participants with ATTR-CM, acoramidis reduced the composite of ACM or first CVH vs placebo, with an early effect driven by a reduction in CVH. (Efficacy and Safety of AG10 in Subjects With Transthyretin Amyloid Cardiomyopathy [ATTRibute-CM]; NCT03860935).