Abstract
Abstract BACKGROUND: Habitual consumption of green tea has been epidemiologically correlated with low risk of cancer. Among various constituents of green tea, catechins are experimentally suggested to have benefitial activity. Especially, (-)-epigallocatechin gallate (EGCG) is the most bioactive constituent. Decreased activation of carcinogenic compounds by inhibition CYP3A4 is proposed as one of mechanisms of anticarcinogenic effect. Green tea is one of the most popular beverages in Japan and Asian countries, and patients often take drugs with green tea beverages. Co-administration of oral cancer medicine which is metabolized by CYP3A4 with green tea may cause harmful interactions. PURPOSE: We investigated the effect of green tea beverage intake on pharmacokinetics of etoposide in an open label, single-dose, randomized, two-way crossover study. METHODS: Patients with various cancers were randomly assigned to receive an etoposide 50-mg capsule either with 600mL green tea beverage or 600mL of water, separated by at least 72-hours washout period. Blood samples were collected for 24 hours. Etoposide concentrations in plasma were determined by high performance liquid chromatography. Plasma pharmacokinetic parameters, including area under the curve (AUC), maximum concentration (Cmax) and elimination half-life (t1/2) were calculated by non-compartment analysis using WinNonlin software. RESULTS: Twenty-five cancer patients (11 males, 14 females; median (range) age, 63 years (46 to 81 years)) participated in this study. Co-administration with green tea resulted in an unexpected decrease by 24.8% in the AUC (p= 0.0003) of etoposide (Table). Carry-over effect was denied. CONCLUSION: Green tea reduces rather than increases exposure to orally administered etoposide.Mean pharmacokinetic parameters of etoposideParameters Water Green teaP-valueAUC 337.61257.45P=0.0003(mg*min/ml) Cmax (mcg/ml) 2.97252.1284P=0.0004t1/2 (h) 7.43116.7696P=0.0771 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2600.
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