PT  - JOURNAL ARTICLE
AU  - Lisa M. Almond
AU  - Sophie Mukadam
AU  - Iain Gardner
AU  - Krystle Okialda
AU  - Susan Wong
AU  - Oliver Hatley
AU  - Suzanne Tay
AU  - Karen Rowland-Yeo
AU  - Masoud Jamei
AU  - Amin Rostami-Hodjegan
AU  - Jane R. Kenny
TI  - Prediction of Drug-Drug Interactions Arising from CYP3A induction Using a Physiologically Based Dynamic Model
AID  - 10.1124/dmd.115.066845
DP  - 2016 Jun 01
TA  - Drug Metabolism and Disposition
PG  - 821--832
VI  - 44
IP  - 6
4099  - http://dmd.aspetjournals.org/content/44/6/821.short
4100  - http://dmd.aspetjournals.org/content/44/6/821.full
SO  - Drug Metab Dispos2016 Jun 01; 44
AB  - Using physiologically based pharmacokinetic modeling, we predicted the magnitude of drug-drug interactions (DDIs) for studies with rifampicin and seven CYP3A4 probe substrates administered i.v. (10 studies) or orally (19 studies). The results showed a tendency to underpredict the DDI magnitude when the victim drug was administered orally. Possible sources of inaccuracy were investigated systematically to determine the most appropriate model refinement. When the maximal fold induction (Indmax) for rifampicin was increased (from 8 to 16) in both the liver and the gut, or when the Indmax was increased in the gut but not in liver, there was a decrease in bias and increased precision compared with the base model (Indmax = 8) [geometric mean fold error (GMFE) 2.12 vs. 1.48 and 1.77, respectively]. Induction parameters (mRNA and activity), determined for rifampicin, carbamazepine, phenytoin, and phenobarbital in hepatocytes from four donors, were then used to evaluate use of the refined rifampicin model for calibration. Calibration of mRNA and activity data for other inducers using the refined rifampicin model led to more accurate DDI predictions compared with the initial model (activity GMFE 1.49 vs. 1.68; mRNA GMFE 1.35 vs. 1.46), suggesting that robust in vivo reference values can be used to overcome interdonor and laboratory-to-laboratory variability. Use of uncalibrated data also performed well (GMFE 1.39 and 1.44 for activity and mRNA). As a result of experimental variability (i.e., in donors and protocols), it is prudent to fully characterize in vitro induction with prototypical inducers to give an understanding of how that particular system extrapolates to the in vivo situation when using an uncalibrated approach.