Clinical Pharmacology & Therapeutics / Influence of OATPs on Hepatic Disposition of Erlotinib Measured With Positron Emission Tomography

To assess the hepatic disposition of erlotinib, we performed positron emission tomography (PET) scans with [C]erlotinib in healthy volunteers without and with oral pretreatment with a therapeutic erlotinib dose (300mg). Erlotinib pretreatment significantly decreased the liver exposure to [C]erlotinib with a concomitant increase in blood exposure, pointing to the involvement of a carriermediated hepatic uptake mechanism. Using cell lines overexpressing human organic aniontransporting polypeptides (OATPs) 1B1, 1B3, or 2B1, we show that [C]erlotinib is selectively transported by OATP2B1. Our data suggest that at PET microdoses hepatic uptake of [C]erlotinib is mediated by OATP2B1, whereas at therapeutic doses OATP2B1 transport is saturated and hepatic uptake occurs mainly by passive diffusion. We propose that [C]erlotinib may be used as a hepatic OATP2B1 probe substrate and erlotinib as an OATP2B1 inhibitor in clinical drugdrug interaction studies, allowing the contribution of OATP2B1 to the hepatic uptake of drugs to be revealed.(VLID)481531