Tafamidis (Fx-1006A) is a kinetic stabilizer of transthyretin (TTR) that prevents amyloidogenesis by wild-type and mutant TTRs. It binds to TTR with negative cooperativity (Kd1: 3 nM; Kd2: 278 nM) to stabilize the TTR dimer-dimer interface and inhibit tetrameric dissociation. Tafamidis stabilizes wild-type and clinically significant V30M and V122I mutant TTR amyloidogenic homotetramers (EC50s: 2.7-3.2 μM) under fibril-promoting, denaturing, and physiological conditions in vitro. It stabilizes TTR heterotetramers containing wild-type and mutant subunits ex vivo in human plasma derived from patients carrying V30M or V1221 mutations when used at a concentration of 7.2 μM. Formulations containing tafamidis have been used for the treatment of familial amyloid polyneuropathy.