Tafamidis in transthyretin amyloid cardiomyopathy: effects on transthyretin stabilization and clinical outcomes.

BACKGROUND: Transthyretin (TTR) amyloidosis is a progressive systemic disorder caused by misfolded TTR monomers that cumulatively deposit in the heart and systemically as amyloid. METHODS AND RESULTS: This phase 2 open-label trial evaluated the stabilization of TTR tetramers using 20 mg of tafamidis daily at week 6 (primary end point), month 6, and month 12, as well as safety of tafamidis treatment and efficacy with respect to progression of TTR amyloid cardiomyopathy. Thirty-one wild-type patients (median age, 76.7 years; 93.5% men) with a median disease duration of 55.6 months and mild to moderate heart failure (96.8%; New York Heart Association, classes I-II) were enrolled. Thirty of 31 patients (96.8%) achieved TTR stabilization after 6 weeks and 25 of 28 patients (89.3%) after 12 months. After 12 months of treatment, 3 patients discontinued prematurely, 2 patients died, 7 patients were hospitalized because of cardiovascular events, 20 of 28 patients demonstrated preserved New York Heart Association classification status, but 15 of 31 (48.4%) patients had clinical progression (eg, admission for cardiac failure, atrial fibrillation, and syncope). N-terminal prohormone brain natriuretic peptide levels did not increase significantly over time, troponin I and troponin T increased moderately, and no consistent clinically relevant changes were seen in echocardiographic cardiac assessments. Tafamidis treatment was generally well tolerated although 7 of 31 patients had bouts of diarrhea. CONCLUSIONS: Tafamidis treatment effectively achieved and maintained TTR stabilization and was well tolerated. The absence of significant changes in most biochemical and echocardiographic parameters suggests that further evaluation of tafamidis in TTR amyloid cardiomyopathy is warranted. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00694161.

Cardiac findings and events observed in an open-label clinical trial of tafamidis in patients with non-Val30Met and non-Val122Ile hereditary transthyretin amyloidosis.

A phase 2, open-label study in 21 patients with non-Val30Met and non-Val122Ile hereditary transthyretin amyloidosis showed that tafamidis (20 mg daily for 12 months) stabilized these transthyretin variants. We assessed cardiac amyloid infiltration and cardiac abnormalities in this same study population. At baseline, median age was 64.3 years, 11 patients were in NYHA class II, 13 had conduction abnormalities, 14 N-terminal pro-hormone brain natriuretic peptide concentrations >300 pg/ml, and 17 interventricular septal thickness >12 mm. Mean (SD) left ventricular ejection fraction was 60.3% (9.96). Patients with normal heart rate variability increased from 4/19 at baseline to 8/19 at month 12 (p < 0.05). Cardiac biomarkers remained stable. Although four patients had increases in interventricular septal thickness ≥ 2 mm, the remainder had stable septal wall thickness. There were no clinically relevant changes in mean echocardiographic/electrocardiographic variables and no safety concerns.