Intravenous-to-oral switch in anticancer chemotherapy: a focus on docetaxel and paclitaxel.

Oral administration of the taxanes docetaxel and paclitaxel is hampered by their affinity for drug transporters, especially ABCB1 (P-glycoprotein, Pgp); extensive first-pass metabolism by cytochrome P450 3A (CYP3A); and poor drug solubility. Preclinical studies in Pgp-deficient and wild-type mice demonstrated that modulation of either Pgp or CYP3A resulted in high systemic exposure to docetaxel or paclitaxel. This concept could successfully be translated to clinical trials.