Einolf, Heidi (2014) Using Calibration Curve-based Approaches of RIS, R3, Cmax/EC50, and AUC/F2, from mRNA and Activity Induction Data in Human Hepatocytes to Predict Clinical Inducers and Non-inducers of CYP3A4. Drug Metabolism and Disposition, 42 (9). pp. 1379-1391. ISSN 1521-009X

Abstract

Cytochrome P450 (CYP) induction is generally considered a liability in drug development. Using a calibration curve-based approach, we assessed the induction parameters R3, relative induction score (RIS), Cmax/EC50 and AUC/F2, derived from concentration-response curves of CYP3A4 mRNA and enzyme activity data in vitro, as predictors of CYP3A4 induction potential in vivo. Plated cryopreserved human hepatocytes from three donors were treated with 20 test compounds, including several established clinical inducers or non-inducers of CYP3A4. After the two day treatment, CYP3A4 mRNA levels and testosterone 6ß-hydroxylase activity were determined by RT-PCR and LC-MS/MS analysis, respectively. Our results demonstrated a strong and predictive relationship between the extent of midazolam AUC change in human and the various parameters calculated from both CYP3A4 mRNA and enzyme activity. The relationship evaluated with non-midazolam in vivo probes, in aggregate, were less compelling. In general, the models yielded better fits when unbound rather than total plasma Cmax was used to calculate the induction parameters, as evidenced by higher R2 and lower RMSE and GMFE values. With midazolam, the R3 cut-off value of 0.9, as suggested by FDA guidance, effectively categorized strong inducers, but was less effective in classifying mid-range or weak inducers. This study supports the use of calibration curves generated from in vitro mRNA induction response curves to predict CYP3A4 induction potential in human. With the caveat that compounds should not be strong inhibitors, enzyme activity was also demonstrated to be a strong predictor of CYP3A4 induction potential in this assay model.

Item Type:	Article
Date Deposited:	12 Oct 2016 00:45
Last Modified:	12 Oct 2016 00:45
URI:	https://oak.novartis.com/id/eprint/21512