The influence of verapamil on the pharmacokinetics of the pan-HER tyrosine kinase inhibitor neratinib in rats: the role of P-glycoprotein-mediated efflux.

Summary: Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, has been approved for the treatment of HER2-positive (HER2⁺) early-stage and brain metastatic breast cancer. Thus far, the pharmacology effects and pharmacodynamics of neratinib have been well studied. However, the disposition of neratinib and its influencing factors in vivo remain unclear. P-glycoprotein (P-gp), one of the most extensively studied transporters, substantially restricts penetration of drugs into the body or deeper compartments (i.e., blood-brain barrier, BBB), regarding drug resistance and drug-drug interactions. Thereby, the aim of this study was to investigate the influence of verapamil (a P-gp inhibitor) on the pharmacokinetics of neratinib in rats. Here, we have established a high specific, selective and sensitive ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method to quantify plasma concentrations of neratinib in rats. Pharmacokinetic results showed that verapamil significantly increased the system exposure of neratinib, as C_max increased by 2.09-fold and AUC_0-t increased by 1.64-fold, respectively. Additionally, the in vitro transport of neratinib was evaluated using Madin-Darby canine kidney II (MDCK II) and human MDR1 gene overexpressed MDCK (MDCK-MDR1) cell line models. As a result, the net flux ratio was over than 2 and decreased over 50% by verapamil, suggesting that neratinib was a substrate of P-gp. Hence, our findings have highlighted the important role of P-gp in the system exposure of neratinib in vivo, and drug-drug interaction should be considered when coadministration of P-gp inhibitors with neratinib. These findings may support the further clinical development and application of neratinib. [ABSTRACT FROM AUTHOR]