Primary endpoint met with therapy for transthyretin cardiomyopathy
The Tafamidis Phase 3 Transthyretin Cardiomyopathy (ATTR-ACT) study evaluating tafamidis for the treatment of transthyretin cardiomyopathy met its primary endpoint, demonstrating a statistically significant reduction in the combination of all-cause mortality and frequency of cardiovascular-related hospitalizations compared to placebo at 30 months. The preliminary safety data showed that tafamidis was generally well tolerated in this population and no new safety signals were identified.
The ATTR-ACT study was designed to assess clinically meaningful outcomes for the use of tafamidis as a treatment for patients with transthyretin cardiomyopathy, a rare, fatal, and underdiagnosed condition associated with progressive heart failure. The average life expectancy for people with transthyretin cardiomyopathy is 3 to 5 years from diagnosis. The prevalence of transthyretin cardiomyopathy is presently unknown; however, it is estimated that less than 1% of people with the disease are diagnosed. Currently, there are no approved pharmacological medications specifically indicated for treating transthyretin cardiomyopathy.
ATTR-ACT is a Phase 3 international, multicenter, double-blind, placebo-controlled, randomized, 3-arm clinical study in 441 patients that investigated the efficacy, safety, and tolerability of an oral daily dose of 20 mg or 80 mg tafamidis meglumine capsules compared to placebo. Tafamidis meglumine is a specific stabilizer of transthyretin.
The ATTR-ACT study included both patients with the variant, or hereditary, form of the disease, and those with the wild-type form, which is not hereditary and may occur as people age. The primary analysis of the study, which compared tafamidis to placebo, was the hierarchical combination of all-cause mortality and frequency of cardiovascular-related hospitalizations over a 30-month period in patients with transthyretin cardiomyopathy.
In 2011, tafamidis was granted orphan drug designation for transthyretin cardiomyopathy in both the EU and US. In June 2017, the US Food and Drug Administration (FDA) granted Fast Track designation to tafamidis for transthyretin cardiomyopathy; additionally, in March 2018, the Ministry of Labor Health and Welfare in Japan granted SAKIGAKE designation to tafamidis for this indication.