Quantitative Prediction of OATP-Mediated Disposition and Biliary Clearance Using Human Liver Chimeric Mice

Drug biliary clearance (CL_bile) in vivo is among the most difficult pharmacokinetic parameters to predict accurately and quantitatively because biliary excretion is influenced by metabolic enzymes, transporters, and passive diffusion across hepatocyte membranes. The purpose of this study is to demonstrate the use of Hu-FRG mice [Fah (FRG) mice transplanted with human-derived hepatocytes] to quantitatively predict human organic anion transporting polypeptide (OATP)-mediated drug disposition and CL_bile To predict OATP-mediated disposition, six OATP substrates (atorvastatin, fexofenadine, glibenclamide, pitavastatin, pravastatin, and rosuvastatin) were administered intravenously to Hu-FRG and Mu-FRG mice (FRG mice transplanted with mouse hepatocytes) with or without rifampicin as an OATP inhibitor. We calculated the hepatic intrinsic clearance (CL_h,int) and the change of hepatic clearance (CL_h) caused by rifampicin (CL_h ratio). We compared the CL_h,int of humans with that of Hu-FRG mice and the CL_h ratio of humans with that of Hu-FRG and Mu-FRG mice. For predicting CL_bile, 20 compounds (two cassette doses of 10 compounds) were administered intravenously to gallbladder-cannulated Hu-FRG and Mu-FRG mice. We evaluated the CL_bile and investigated the correlation of human CL_bile with that of Hu-FRG and Mu-FRG mice. We found good correlations between humans and Hu-FRG mice in CL_h,int (100% within threefold) and CL_h ratio (R² = 0.94). Moreover, we observed a much better relationship between humans and Hu-FRG mice in CL_bile (75% within threefold). Our results suggest that OATP-mediated disposition and CL_bile can be predicted using Hu-FRG mice, making them a useful in vivo drug discovery tool for quantitatively predicting human liver disposition. SIGNIFICANCE STATEMENT: OATP-mediated disposition and biliary clearance of drugs are likely quantitatively predictable using Hu-FRG mice. The findings can enable the selection of better drug candidates and the development of more effective strategies for managing OATP-mediated DDIs in clinical studies.