RT Journal Article SR Electronic T1 Simulation of Clinical Drug-Drug Interactions from Hepatocyte CYP3A4 Induction Data and Its Potential Utility in Trial Designs JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 1139 OP 1148 DO 10.1124/dmd.111.038067 VO 39 IS 7 A1 Yang Xu A1 Yihong Zhou A1 Mike Hayashi A1 Magang Shou A1 Gary L. Skiles YR 2011 UL http://dmd.aspetjournals.org/content/39/7/1139.abstract AB Rifampin and carbamazepine have been recommended in the U.S. Food and Drug Administration draft drug interaction guidance as CYP3A4 inducers for clinical drug-drug interaction (DDI) studies. To optimize the dose regimens of these inducers for use in DDI studies, their effect at various doses and dosing durations on the area under the curve (AUC) of multiple probe substrates was simulated using a population-based simulator. A similar assessment of the inducer phenobarbital was also conducted. CYP3A4 induction by all three inducers was previously determined in hepatocytes, and the results were incorporated into simulations. The pharmacokinetics of the three inducers and their associated CYP3A4 drug interactions were predicted and compared with in vivo observations. The predicted Cmax and AUC of all the inducers and substrates correlated closely with those observed clinically. The predicted magnitudes of the DDIs caused by CYP3A4 induction were also in good agreement with the observed clinical results. Comparison of the maximal CYP3A4 induction potential among the three inducers indicated that rifampin is the most potent inducer and is the best choice for clinical CYP3A4 induction DDI studies. Moreover, a near-maximal CYP3A4 DDI was predicted to result from administration of rifampin for approximately 7 days at 450 to 600 mg q.d. or 200 to 300 mg b.i.d. These results suggest optimal dose regimens for clinical trials that maximize the probability of detecting a DDI caused by CYP3A4 induction. The simulation strategy provides the means to predict the induction profiles of compounds in development.