Transthyretin amyloid cardiomyopathy is a rare and fatal disease for which there are no previously approved treatments.
Officials with the FDA have approved tafamidis meglumine and tafamidis (Vyndaqel and Vyndamax, Pfizer) for transthyretin amyloid cardiomyopathy (ATTR-CM), a rare and life-threatening disease that is defined by restrictive cardiomyopathy and progressive heart failure, according to a press release.
Both treatments, which are oral formulations of transthyretin stabilizer tafamidis, are approved to treat either wild-type or hereditary ATTR-CM. There are approximately 100,000 individuals in the United States with ATTR-CM, of whom only 1% to 2% are diagnosed today, according to Pfizer.
The approval is based on data from the phase 3 Transthyretin Amyloidosis Cardiomyopathy Clinical Trial. According to the results, tafamidis meglumine significantly reduced the hierarchical combination of all-cause mortality and frequency of cardiovascular-related hospitalizations compared with a placebo over a 30-month period. Individual components of the primary analysis also demonstrated a relative reduction in the risk of all-cause mortality and frequency of cardiovascular-related hospitalization of 30% and 32%, according to the study.
ATTR-CM is caused by destabilization of transthyretin, a transport protein, and is characterized by the buildup of abnormal deposits of amyloid in the heart. There are 2 types of ATTR-CM: hereditary and wild-type. Hereditary ATTR-CM results from a mutation in the transthyretin gene and can occur in individuals as early as their 50s or 60s. The wild-type form of the disease occurs without mutation and is associated with aging, usually affecting men over the age of 60. Once diagnosed, the median life expectancy for patients, dependent on sub-type, is approximately 2 to 3.5 years.
Prior to this approval, there were no available treatments for ATTR-CM, only symptom management and, in rare cases, heart transplant.
“ATTR-CM is not only fatal, but also significantly underdiagnosed, with some patients cycling through multiple doctors and a myriad of tests over a period of years while the disease progresses,” Isabella Lousada, Founder and CEO of Amyloidosis Research Consortium, said in a statement. “ATTR-CM is a rare disease for which more education and awareness is needed. The approval of these medicines represents an important advance for patients; however, it is equally important that we work as a community to recognize the critical importance of early diagnosis.”
The recommended dosage for treatment is either tafamidis meglumine 80 mg orally once-daily, taken as four 20-mg capsules, or tafamidis 61 mg orally once-daily, taken as a single capsule.
Tafamidis meglumine was previously approved in 2011 in the European Union for the treatment of transthyretin amyloid polyneuropathy in adults with early-stage symptomatic polyneuropathy to delay peripheral neurologic impairment.
US FDA Approves Vyndaqel and Vyndamax for Use in Patients with Transthyretin Amyloid Cardiomyopathy, a Rare and Fatal Disease [news release]. Pfizer. https://www.pfizer.com/news/press-release/press-release-detail/u_s_fda_approves_vyndaqel_and_vyndamax_for_use_in_patients_with_transthyretin_amyloid_cardiomyopathy_a_rare_and_fatal_disease. Accessed May 6, 2019.