TY - JOUR T1 - Characterization of Fasiglifam-Related Liver Toxicity in Dogs JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 525 LP - 534 DO - 10.1124/dmd.118.084889 VL - 47 IS - 5 AU - Akifumi Kogame AU - Yuu Moriya AU - Ikuo Mori AU - Liping Pan AU - Akio Morohashi AU - Takuya Ebihara AU - Hideo Fukui AU - Yoshihiko Tagawa AU - Leslie Z. Benet Y1 - 2019/05/01 UR - http://dmd.aspetjournals.org/content/47/5/525.abstract N2 - Fasiglifam, a potent and highly selective agonist of G protein-coupled receptor 40, was developed for the treatment of type 2 diabetes mellitus. However, phase III clinical programs were terminated owing to liver safety concerns. Fasiglifam-related liver toxicity was also observed in repeat-dose dog toxicology studies, characterized by granulomatous inflammation with crystal formation in the liver and/or bile ducts. These histopathological changes were not observed in rat toxicology studies. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of dog liver sections obtained from a repeat-dose toxicology study indicated that the crystalline material in the affected dog liver contained fasiglifam and fasiglifam glucuronide (fasiglifam-G). Nonclinical mechanistic studies indicated that after 14 days of repeated oral dosing with [14C]fasiglifam at 200 mg/kg per day to dogs, the concentrations of fasiglifam and fasiglifam-G in the bile exceeded the solubility limit of these compounds in the bile (approximately 3000 µg/ml). After single oral 2- and 200-mg/kg doses administered to rats and dogs, fasiglifam and fasiglifam-G concentrations in dog bile were 5- to 10-fold higher than those in rat bile for the same dose of fasiglifam, while the bile flow rate adjusted by body weight was 4- to 8-fold lower in dogs than in rats. High fasiglifam and fasiglifam-G concentrations in dog bile together with lower bile flow rate could cause crystal formation in dog bile, resulting in secondary granulomatous inflammation in the dog liver. ER -