Quantitative Prediction of CYP3A4 Induction: Impact of Measured, Free, and Intracellular Perpetrator Concentrations from Human Hepatocyte Induction Studies on Drug-Drug Interaction Predictions

Abstract

Typically, concentration-response curves are based upon nominal inducer concentrations for in-vitro-to-in-vivo extrapolation of CYP3A4 induction. The limitation of this practice is that it assumes the hepatocyte culture model is a static system. We assessed whether correcting for: 1) changes in perpetrator concentration in the induction medium during the incubation period, 2) perpetrator binding to proteins in the induction medium, and 3) nonspecific binding of perpetrator can improve the accuracy of CYP3A4 induction predictions. Of the seven compounds used in this evaluation, significant parent loss and nonspecific binding were observed for rifampicin (29.3-38.3%), pioglitazone (64.3-78.6%), and rosiglitazone (57.1-75.5%). As a result, the free measured EC values (EC) of pioglitazone, rosiglitazone, and rifampicin were significantly lower than the nominal EC values. In general, the accuracy of the induction predictions, using multiple static models, improved when corrections were made for measured medium concentrations, medium protein binding, and nonspecific binding of the perpetrator, as evidenced by 18-29% reductions in the root mean square error. The relative induction score model performed better than the basic static and mechanistic static models, resulting in lower prediction error and no false-positive or false-negative predictions. However, even when the EC value was used, the induction prediction for bosentan, which is a substrate of organic anion transporter proteins, was overpredicted by approximately 2-fold. Accounting for the ratio of unbound intracellular concentrations to unbound medium concentrations (K) (0.5-7.5) and the predicted multiple-dose K (0.6) for bosentan resulted in induction predictions within 35% of the observed interaction.

A Study on Pharmacokinetics of Bosentan with Systems Modeling, Part 1: Translating Systemic Plasma Concentration to Liver Exposure in Healthy Subjects

“…Understanding bosentan liver exposure is also important for predicting cytochrome P450 (P450) induction and inhibition. Several groups have reported that bosentan is an inducer for P450s (van Giersbergen et al, 2002a;Dingemanse and van Giersbergen, 2004;Fahmi et al, 2008;Srinivas, 2016;Sun et al, 2017). Results of in vitro studies also show that bosentan inhibits the bile salt export pump (BSEP), multidrug resistance-associated proteins (MRPs) 3 and 4 ( Morgan et al, 2013), and sodium-taurocholate cotransporting polypeptide (NTCP) (Leslie et al, 2007), which may result in drug-induced liver injury (DILI) (Leslie et al, 2007;Morgan et al, 2013).…”

Considerations from the Innovation and Quality Induction Working Group in Response to Drug-Drug Interaction Guidances from Regulatory Agencies: Focus on CYP3A4 mRNA In Vitro Response Thresholds, Variability, and Clinical Relevance

“…2). Additionally, differences in intracellular drug concentration in response to changes in enzyme or transporter expression could contribute to a range of induction responses in inter-and intradonor experiments (Chu et al, 2013;Sun et al, 2017).…”

Comparison of Species and Cell-Type Differences in Fraction Unbound of Liver Tissues, Hepatocytes, and Cell Lines

“…For in vitro cellbased assays, such as metabolic stability, induction, inhibition, and pharmacological assays, f u measurements of hepatocytes or other cell types [ f u of cells ( f u,cell )] allows for the determination of intracellular free drug concentration (Mateus et al, 2013;Riccardi et al, 2016Riccardi et al, , 2017. Intracellular free drug concentration, rather than nominal concentration, is most relevant for compounds with intracellular accumulation or exclusion to develop in vitro-in vivo correlations for human translation and to understand the in vitro absorption, distribution, metabolism, excretion, and toxicity and pharmacology endpoints (Riccardi et al, 2016(Riccardi et al, , 2017Mateus et al, 2017;Riede et al, 2017;Sun et al, 2017). Using intracellular free drug concentration, the unbound partition coefficient (K puu ) can be determined and used to derive intrinsic activity for in vitro cell-based assays (e.g., CL int = CL int 9/K puu , EC 50 = EC 50 9 Â K puu , IC 50 = IC 50 9 Â K puu , where CL int is intrinsic clearance, CL int 9 is apparent intrinsic clearance, EC 50 9 is apparent EC 50 , and IC 50 9 is apparent IC 50 ).…”