Prediction of clinical CYP3A4 induction using cryopreserved human hepatocytes.

1. The purpose of this study was to construct a method to predict CYP3A4 induction in the clinical setting from in vitro data using cryopreserved human hepatocytes. 2. We recently developed an approach with in vitro assays of HepaRG cell lines for predicting CYP3A4 induction by using a novel value, termed the relative factor (RF), determined from the ratio of the concentration of an inducer to the reference standard. In this study, the applicability of the RF approach was expanded to cryopreserved human hepatocytes. 3. Induction assays were performed in vitro using hepatocytes from four individual donors and eight typical inducers. The obtained RF values were related to the free plasma concentration of each inducer (expressed as Css,u/RF). 4. A good relationship between the Css,u/RF values and the in vivo induction response was found for all donors. Inducers were classified by the Css,u/RF values into three categories for CYP3A4 induction risk (high, medium and low potency), and thereby the degree of CYP3A4 induction in vivo in humans could be predicted from the Css,u/RF values. 5. The RF approach is applicable to human cryopreserved hepatocytes. Thus, a method to predict the potency of CYP3A4 inducers was constructed using cryopreserved human hepatocytes.