Diflunisal for ATTR cardiac amyloidosis

Abstract

Transthyretin (TTR) cardiac amyloidosis is an important, often under-recognized and potentially modifiable cause of heart failure with a preserved ejection fraction. The only proven treatment is liver or combined heart/liver transplantation, which, although effective, is not suitable for the vast majority of older adults with this condition. Diflunisal, a nonsteroidal anti-inflammatory drug, can stabilize the TTR tetramer in vitro and may prevent misfolding monomers and dimers from forming amyloid deposits in the heart. It is one of two small molecules assessed in animal safety studies and human clinical trials of TTR polyneuropathy. The authors conducted a single-arm, open-label investigation with a mean follow-up of 0.9 ± 0.3 years to determine the safety and efficacy of diflunisal administration in a cohort of 13 patients with confirmed wild-type or mutant TTR cardiac amyloidosis. Diflunisal was well tolerated from a hematologic standpoint, although a 6% decline in estimated glomerular filtration rate was noted. Therapy was discontinued in one patient who rapidly developed volume overload. There was no significant mean change in cardiac structure (left ventricular mass: -53 g/m(2) change, P=.36), function (ejection fraction: -2% change, P=.61), or biomarkers (Troponin I: +0.03 ng/mL, P=.08; BNP: +93 pg/mL change, P=.52) during the course of therapy. These data suggest that at low dosages and with careful monitoring, diflunisal can be safely administered to compensated patients with cardiac TTR amyloidosis. Further study in a randomized placebo-controlled trial is warranted.

FIGURE

Comparison between mean baseline and follow-up safety parameters show a trend towards decrease in glomerular filtration rate (GFR) but a stable hemoglobin (A), modified body mass index (mBMI), and mean arterial pressure (MAP) (B). With regard to efficacy, trends between mean baseline and follow-up metrics show a mild increase in B-type natriuretic peptide (BNP) and Troponin (Tr) I (C), stable left ventricular (LV) mass, and a stable ejection fraction (EF) (D). Standard error bars are shown.