Treatment With Tafamidis Slows Disease Progression in Early-Stage Transthyretin Cardiomyopathy

Background: Transthyretin cardiomyopathy (TTR-CM) is a progressive, fatal disease caused by the accumulation of misfolded transthyretin (TTR) amyloid fibrils in the heart. Tafamidis is a kinetic stabilizer of TTR that inhibits misfolding and amyloid formation. Methods: In this post hoc analysis, data from an observational study (Transthyretin Amyloidosis Cardiac Study; n = 29) were compared with an open-label study of tafamidis in patients with TTR-CM (Fx1B-201; n = 35). To ensure comparable baseline disease severity, patients with New York Heart Association (NYHA) functional classification ≥III were excluded in this time-to-mortality analysis. Results: Patients with either wild-type or Val122Ile genotypes treated with tafamidis have a significantly longer time to death compared with untreated patients ( P = .0004). Similar results were obtained when limiting the analysis to wild-type patients only, without restricting NYHA functional classification ( P = .0262). Conclusions: These results support earlier conclusions suggesting that tafamidis slows disease progression compared with no treatment outside of standard of care and warrant further investigation. Trial Registration: ClinicalTrials.gov, NCT00694161.