Pfizer Inc. announced that 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.

“These topline results are important for people with transthyretin cardiomyopathy and bring us one step closer to realizing the potential for a new treatment for those in desperate need,” said Brenda Cooperstone MD, senior vice president and chief development officer, rare disease, Pfizer Global Product Development. “Pfizer Rare Disease has been at the forefront of improving the understanding of transthyretin cardiomyopathy, and we thank the patients who participated in the trial and their families, as well as the physicians and investigational sites that contributed to this important study. We look forward to sharing the detailed results of the study with the cardiovascular community and discussing these data with health authorities to determine an appropriate regulatory path forward.”

“Our findings offer real hope for people with transthyretin cardiomyopathy and their families,” said Mat Maurer MD, Arnold and Arlene Goldstein professor of Cardiology, Columbia University Vagelos College of Physicians and Surgeons. “As health care professionals, all we can do right now is manage symptoms of the disease, as there are no approved pharmacological treatment options at this time. The need for medicines that treat transthyretin cardiomyopathy is critical.”

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.

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. The 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.

Tafamidis is an investigational treatment for transthyretin cardiomyopathy and is not approved for this indication.