New Drug Review: Tafamidis Meglumine for Cardiomyopathy

In May 2019, the FDA approved tafamidis meglumine (Vyndaqel, FoldRx, a subsidiary of Pfizer). It is one of the first FDA-approved treatments for heart disease (cardiomyopathy) caused by transthyretin-mediated amyloidosis (ATTR-CM) in adults.¹ Transthyretin-mediated amyloidosis is described as a rare, slow progressive condition caused by the buildup of abnormal deposits of proteins in the body’s tissues and organs, debilitating their normal daily function. Tafamidis meglumine was granted Fast Track, Priority Review, and Breakthrough Therapy designations by the FDA. Additionally, this medication received Orphan Drug designation.¹

Efficacy

The FDA approved tafamidis meglumine primarily based on the results of a double-blind, randomized, 441-participant clinical trial during which participants received either tafamidis meglumine or placebo.² Patients aged between 18 to 90 years old with transthyretin amyloid cardiomyopathy (ATTRwt or ATTRm) confirmed by the presence of amyloid deposits on analysis of biopsy specimens obtained from cardiac and noncardiac sites, and in patients without ATTRm, by the presence of transthyretin precursor protein confirmed on immunohistochemical analysis, scintigraphy, or mass spectrometry were eligible. Patients were excluded if any one of the following criteria were met: heart failure that was not due to transthyretin amyloid cardiomyopathy, New York Heart Association (NYHA) class IV heart failure, the presence of light-chain amyloidosis, a history of liver or heart transplantation, an implanted cardiac device, previous treatment with tafamidis, an estimated glomerular filtration rate lower than 25 ml per minute per 1.73 m² of body surface area, or liver transaminase levels exceeding two times the upper limit of the normal range.³ Patients were given 20 mg tafamidis, 80 mg tafamidis, or placebo administered once a day for 30 months. The primary outcome measure was to assess all-cause mortality, followed by frequency of cardiovascular-related hospitalizations over the course of the 30-month trial. ³ The results showed all-cause mortality was lower with tafamidis than with placebo (78 of 264 [29.5%] vs. 76 of 177 [42.9%]; hazard ratio, 0.70; 95% CI, 0.51 to 0.96). The rate of cardiovascular-related hospitalizations (0.48 vs. 0.70 hospitalizations per year; relative risk ratio, 0.68; 95% CI, 0.56 to 0.81) was lower with tafamidis than with placebo.³

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Safety

As of publication, there are no known adverse effects associated with tafamidis.⁴

Dosing

In patients with confirmed cardiomyopathy of wild type or hereditary transthyretin-mediated amyloidosis to reduce death and hospitalization related to heart problems, the recommended dosing for tafamidis meglumine is 80 mg daily by mouth. Doses may not be crushed or cut. If a dose is missed, take the dose as soon as remembered or skip the missed dose and take the next dose at the regularly scheduled time. It is important not to double the dose. Tafamidis meglumine currently has no known drug interactions. Patients should not take tafamidis meglumine if they are pregnant or plan to become pregnant, or if they are breastfeeding or plan to breastfeed. As of right now, the safety and effectiveness of tafamidis meglumine have not been established in pediatric patients. For geriatric patients, no dosage adjustment is required.⁴

References:

1. U.S.A. Food and Drug Administration. FDA approves new treatments for heart disease caused by a serious rare disease, transthyretin mediated amyloidosis. Accessed September 21, 2019.

2. ClinicalTrials.gov. Safety and efficacy of tafamidis in patients with transthyretin cardiomyopathy (ATTR-ACT). Accessed September 21, 2019.

3. Maurer MS, Schwartz JH, Gundapaneni B, et al. Tafamidis treatment for patients with transthyretin amyloid cardiomyopathy. N Engl J Med. 2018;379(11):1007-1016.

4. Tafamidis meglumine [package insert]. New York, NY. Pfizer Labs; 2019. Accessed September 21, 2019.