Association of Abcg2 Polymorphism with Plasma Concentrations of Axitinib in Patients with Renal Cell Carcinoma

Background: Axitinib is a selective inhibitor for VEGF receptors 1, 2, and 3 on renal cell carcinoma (RCC). The plasma concentrations and area under the blood concentration-time curve (AUC) of axitinib are known to correlate with response rate and survival rate in RCC patients. Breast cancer resistance protein (BCRP, ABCG2 gene) is an efflux ABC transporter, which is expressed at the apical membrane in intestine, and is involved in the absorption and excretion of various drugs. Several studies have demonstrated that ABCG2 polymorphism affects blood concentrations of oral anticancer drugs, especially molecular targeted drugs. To explore the relationship between pharmacokinetics and pharmacogenetics, we analyzed plasma concentrations of axitinib and ABCG2 polymorphism in RCC patients.