ORIGINAL RESEARCH ARTICLE Pharmacokinetic Drug Interaction Studies with Enzalutamide

The Author(s) 2015. This article is published with open access at Springerlink.com Background and Objectives Two phase I drug interaction studies were performed with oral enzalutamide, which is approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Methods A parallel-treatment design (n = 41) was used to evaluate the effects of a strong cytochrome P450 (CYP) 2C8 inhibitor (oral gemfibrozil 600 mg twice daily) or strong CYP3A4 inhibitor (oral itraconazole 200 mg once daily) on the pharmacokinetics of enzalutamide and its active metabolite N-desmethyl enzalutamide after a single dose of enzalutamide (160 mg). A single-sequence cross-over design (n = 14) was used to determine the effects of enzalutamide 160 mg/day on the pharmacokinetics of a single oral dose of sensitive substrates for CYP2C8 (pi