Efficacy and Safety of AG10 in Subjects With Transthyretin Amyloid Cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed condition believed to affect more than 400,000 people worldwide. In ATTR-CM, the accumulation of transthyretin (TTR) amyloid results in thickening and stiffening of the heart, which often leads to heart failure or even death. There are two forms of ATTR-CM: * Wild Type\* This form of the condition primarily develops in older individuals who do not carry gene mutations. * Hereditary\* This form of the condition comes from gene mutations passed down in families. In this study we are researching the investigational drug acoramidis HCl 800 mg administered orally twice a day. Through the study, we want to evaluate the efficacy and safety of acoramidis in patients with ATTR-CM versus placebo. This is a 30 month, randomized, double-blind, placebo-controlled study. This means that, during the 30 month study, investigators conducting the research and study participants will not know whether the study participant is receiving acoramidis or placebo. The primary outcomes of the study are: 1. The impact of acoramidis versus placebo on the change in distance walked on the 6 minute walk test (6MWT) after 12 months of treatment compared to baseline. 2. The impact of acoramidis versus placebo on the hierarchical combination of All-Cause mortality, cumulative frequency of cardiovascular-related hospitalizations, change from baseline in NT-proBNP, and change in from baseline in 6MWT over a 30-month fixed treatment duration. At the end of 30 months, participants may be eligible to receive investigational acoramidis, and there is no placebo. This is called an "open label extension." This separate study may help us better understand the safety related to taking acoramidis over a longer period of time.