Tafamidis attenuates decline of cardiac function in patients with transthyretin amyloid cardiomyopathy: JAMA

In a post hoc analysis of the randomized Tafamidis in Transthyretin Cardiomyopathy Clinical trial, there was less pronounced worsening of left ventricular (LV) stroke volume, LV global longitudinal strain, and LV filling pressure (estimated using septal and lateral E/e′ ratio) in patients treated with tafamidis, 80 mg, vs placebo. The study findings are published in JAMA Cardiology.

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a known progressive, fatal disease caused by the deposition of transthyretin (TTR) amyloid fibrils in the myocardium, leading to cardiomyopathy and symptoms of heart failure. Tafamidis has proven to improve survival in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) compared with placebo. However, its effect on cardiac function has not been fully elucidated.

Researchers conducted an exploratory, post hoc analysis of the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), a multicenter, international, double-blind, placebo-controlled phase 3 randomized clinical trial conducted from December 2013 to February 2018. The ATTR-ACT included 48 sites in 13 counties and enrolled patients aged 18 to 90 years with ATTR-CM. Data were analyzed from July 2018 to September 2023. Patients were randomized to tafamidis meglumine, 80 mg or 20 mg, or placebo for 30 months.

Patients were categorized based on left ventricular (LV) ejection fraction at enrollment as having heart failure with preserved ejection fraction (≥50%), mildly reduced ejection fraction (41% to 49%), or reduced ejection fraction (≤40%). Changes from baseline to month 30 in LV ejection fraction, LV stroke volume, LV global longitudinal strain, and the ratio of early mitral inflow velocity to septal and lateral early diastolic mitral annular velocity (E/e′) were compared in patients receiving tafamidis, 80 mg, vs placebo.

The key findings of the study are

• A total of 441 patients were randomized in ATTR-ACT, and 436 patients had available echocardiographic data.

• Out of 436 included patients, 393 (90.1%) were male, and the mean (SD) age was 74 (7) years. A total of 220 (50.5%), 119 (27.3%), and 97 (22.2%) had heart failure with preserved, mildly reduced, and reduced LV ejection fraction, respectively.

• Over 30 months, there was less pronounced worsening in 4 of the echocardiographic measures in patients receiving tafamidis, 80 mg were 176, vs 177 in placebo (least squares mean difference: LV stroke volume, 7.02 mL; 95% CI, 2.55-11.49; P = .002; LV global longitudinal strain, −1.02%; 95% CI, −1.73 to −0.31; P = .005; septal E/e′, −3.11; 95% CI, −5.50 to −0.72; P = .01; lateral E/e′, −2.35; 95% CI, −4.01 to −0.69; P = .006).

Researchers concluded that “Compared with placebo, tafamidis, 80 mg, attenuated the decline of LV systolic and diastolic function over 30 months in patients with ATTR-CM. Approximately half of patients had mildly reduced or reduced LV ejection fraction at enrollment, suggesting that ATTR-CM should be considered as a possible diagnosis in patients with heart failure regardless of underlying LV ejection fraction.”

Reference: Shah SJ, Fine N, Garcia-Pavia P, et al. Effect of Tafamidis on Cardiac Function in Patients With Transthyretin Amyloid Cardiomyopathy: A Post Hoc Analysis of the ATTR-ACT Randomized Clinical Trial. JAMA Cardiol. Published online November 15, 2023. doi:10.1001/jamacardio.2023.4147.