Drug for Rare Form of Cardiomyopathy Meets Primary Endpoint in Phase III Trial

A new treatment may be a reality for patients with transthyretin cardiomyopathy, a rare condition for which there are no approved therapies, according to top-line results from the phase III ATTR-ACT trial.

The investigational agent tafamidis meglumine reduced the primary composite endpoint of all-cause mortality and cardiovascular-related hospitalizations relative to placebo through 30 months of treatment, drugmaker Pfizer announced Thursday.

The company said “tafamidis was generally well tolerated in this population and no new safety signals were identified” in the trial, which randomized 441 patients to placebo or one of two oral doses of the drug (20 and 80 mg daily).

Although the prevalence of transthyretin cardiomyopathy—which carries a life expectancy of 3 to 5 years from diagnosis—is unknown, it is estimated that less than 1% of affected individuals have been diagnosed, Pfizer said. Both hereditary and nonhereditary forms of the condition are caused by the buildup of misfolded transthyretin, a transport protein, in the heart, leading to progressive heart failure.

“As healthcare professionals, all we can do right now is manage symptoms of the disease, as there are no approved pharmacological treatment options at this time,” said Mathew Maurer, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), in Pfizer’s press release. “The need for medicines that treat transthyretin cardiomyopathy is critical.”

Tafamidis received orphan drug designation in Europe and the United States in 2011 and gained Fast Track status for this indication from the US Food and Drug Administration last year.