Pfizer has released the primary results from the Phase 3 clinical trial of tafamidis, an investigational drug being researched as a potential treatment for transthyretin amyloid cardiomyopathy. For more information, you can view the source press release here, at Pfizer. Alternatively, you can find the published study here, at the New England Journal of Medicine.
About Transthyretin Amyloid Cardiomyopathy
Transthyretin amyloid cardiomyopathy (ATTR-CM) is a rare and progressive condition that is thought to be under-diagnosed. It is caused when the protein transthyretin (which is involved in carrying vitamin A around the body) is unstable, creating misfolded proteins. These proteins may then accumulate to form amyloid fibrils, which are deposited in the body, and particularly in the heart. This can cause damage, and, for some people, may lead to cardiomyopathy (heart muscle disease) or symptoms of heart failure.
ATTR-CM can be hereditary or wild-type (not hereditary, and may develop as people grow older).
Tadamidis is an investigational treatment being developed for transthyretin amyloid cardiomyopathy, but has not been approved for this use yet. In 2012 tafamidis received Orphan Drug Designation in both the US and EU, and in 2018 Japan also awarded the drug this designation. In addition, tafamidis was granted Fast Track and Breakthrough Therapy designations in the US for the treatment of ATTR-CM.
According to the research paper, tafamidis works by binding to the protein transthyretin to prevent dissociation.
The ATTR-ACT Study
The Phase 3 ATTR-ACT trial was a double-blind and randomised trial that involved 441 patients with wild-type or hereditary ATTR-CM. It was designed to evaluate the safety and efficacy of tafamidis in comparison to a placebo.
Analysis of data from the study showed that the patients taking tafamidis had significantly lower rates of mortality compared to the group taking a placebo (29.5% compared to 42.9%). The tafamidis group also had 32% fewer cardiovascular-related hospitalisations than the placebo group.
In addition, the study also found that, after thirty months, patients taking tafamidis showed a smaller decline functional capacity (measured by six minute walk test distance) and in quality of life (as measured by the a questionnaire). Researchers described the safety profile of tafamidis as “comparable to placebo.”
For more information about this study, you can view the original press release here.