Effect of Tafamidis on Renal Function in Patients With Transthyretin Amyloid Cardiomyopathy in ATTR-ACT

Background

Chronic kidney disease (CKD) is common among patients with amyloid cardiomyopathy. Tafamidis was approved for the treatment of transthyretin amyloid cardiomyopathy (ATTR-CM) based on findings from ATTR-ACT (Safety and Efficacy of Tafamidis in Patients With Transthyretin Cardiomyopathy).

Objectives

This post hoc analysis evaluated changes in renal function among patients with ATTR-CM in ATTR-ACT.

Methods

Patients were randomized to receive tafamidis (20 mg and 80 mg pooled) or placebo for 30 months. The change from baseline in the estimated glomerular filtration rate (eGFR) was compared over time. A composite endpoint of all-cause death, dialysis, kidney transplant, or ≥30% decline in eGFR from baseline was analyzed based on the time to first event.

Results

The mean baseline eGFR was 57.5 ± 17.3 and 55.6 ± 16.8 mL/min/1.73 m² in the tafamidis (n = 264) and placebo (n = 177) groups, respectively. At 30 months, patients treated with tafamidis had a significantly smaller decline in eGFR compared with placebo (least squares mean difference = 3.99 mL/min/1.73 m²; 95% CI: 1.31-6.68; P = 0.004). In patients who completed ATTR-ACT, improvement in CKD staging was more common with tafamidis vs placebo treatment (17.7% vs 7.2%; OR: 2.75; 95% CI: 1.10-6.90; P = 0.034). A lower proportion of tafamidis-treated patients reached the composite renal endpoint (crude rates 34.5% vs 44.1%; HR: 0.73, 95% CI: 0.54-0.99; P = 0.040).

Conclusions

Renal function deteriorates over time in patients with ATTR-CM, and tafamidis treatment was associated with a reduction in this deterioration, and a higher incidence of improved eGFR and CKD staging over 30 months compared with placebo. (Safety and Efficacy of Tafamidis in Patients With Transthyretin Cardiomyopathy [ATTR-ACT] NCT01994889)