Effect of Tafamidis on Serum Transthyretin Levels in Non-Trial Patients With Transthyretin Amyloid Cardiomyopathy
Rodney H. Falk, Mia Haddad, Crystal R. Walker, Sharmila Dorbala, Sarah Cuddy
Abstract
BACKGROUND: Transthyretin amyloid (ATTR) cardiomyopathy is slowed by tafamidis, which stabilizes the TTR molecule and reduces the formation of amyloidogenic oligomers. Stabilizers in clinical doses raise serum TTR, which may be a surrogate for the degree of stabilization. OBJECTIVES: This study aims to determine, in a non-trial, unselected population of patients with ATTR cardiomyopathy, the effect of tafamidis on serum levels of TTR, and to compare these with published data of changes in TTR. METHODS: TTR levels were measured before therapy and 3 to 12 months following initiation of tafamidis therapy in all patients seen between May 20, 2019, and March 1, 2021, who had a follow-up visits within 12 months of therapy initiation. RESULTS: 0.057). CONCLUSIONS: Tafamidis consistently increases serum TTR levels in patients with ATTR cardiomyopathy, consistent with its effect on stabilizing TTR. Measurement of TTR level change post-TTR stabilizing therapy might be a surrogate for stabilization and could be a more accurate measure of drug efficacy than an in vitro nonphysiologic test of stabilization.