A key requirement in drug discovery is to accurately define intrinsic clearance (CLint) values of less than 1 µl/min/106 hepatocytes, which requires assays that allow for longer incubation time as a complement to suspended hepatocytes. This study assessed the effectiveness of plated HepaRG cells, plated primary human hepatocytes (PHHs), and the HµREL human hepatocyte/stromal cell co-cultures for determination of low CLint values. The investigation demonstrated that the systems were capable of providing statistically significant CLint estimations down to 0.2 µl/min/106 cells. The HµREL assay provided a higher level of reproducibility, with repeat significant CLint values being defined in a minimum of triplicate consecutive assays for six of seven of the low CLint compounds compared with four of seven for PHHs and two of seven for HepaRG. The assays were also compared with a suspension assay using drugs with higher CLint values and diverse enzymology. The CLint values from the PHH and HµREL assays were similar to those defined by a hepatocyte suspension assay, indicating that they can be used interchangeably alongside a standard assay. Finally, data from these two assays could also predict in vivo hepatic metabolic CLint to within 3-fold for greater than 70% of the compounds tested, with average fold errors (AFE) of 1.6 and 2.3, respectively, whereas the HepaRG data were predictive to within 3-fold for only 50% of compounds (AFE 2.9). In summary, all systems have utility for low CLint determination, but the HµREL co-culture appears slightly superior regarding overall assay performance.
- Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics