P-glycoprotein (MDR1/ABCB1) and Breast Cancer Resistance Protein (BCRP/ABCG2) affect brain accumulation and intestinal disposition of encorafenib in mice

Publication date: Available online 14 November 2017 Source:Pharmacological Research Author(s): Jing Wang, Changpei Gan, Rolf W. Sparidans, Els Wagenaar, Stéphanie van Hoppe, Jos H. Beijnen, Alfred H. Schinkel Encorafenib (LGX818) is a promising BRAFV600E inhibitor that has efficacy against metastatic melanoma. To better understand its pharmacokinetics, we studied its interactions with the multidrug efflux transporters ABCB1 and ABCG2 and the multidrug metabolizing enzyme CYP3A. In polarized MDCK-II cells, encorafenib was efficiently transported by canine and human ABCB1 and ABCG2 and by mouse Abcg2. Upon oral administration to wild-type, Abcb1a/1b−/− , Abcg2−/− , and Abcb1a/1b;Abcg2−/− mice, encorafenib was absorbed very quickly and to very high plasma levels, but without clear changes in oral availability between the strains. Upon oral or intravenous administration, encorafenib brain accumulation was markedly increased in Abcb1a/1b;Abcg2−/− mice and to a lesser extent in Abcb1a/1b−/− mice. However, absolute brain concentrations and brain-to-plasma ratios remained very low in all strains, indicating intrinsically poor brain penetration of encorafenib. Upon intravenous administration, Abcb1a/1b;Abcg2−/− mice showed somewhat reduced plasma elimination of encorafenib compared to wild-type mice, and lower accumulation of the drug in the intestinal tract, suggesting a limited role for these transporters in intestinal elimination of the drug. In Cy...
Source: Pharmacological Research - Category: Drugs & Pharmacology Source Type: research