Determination of soluble vascular endothelial growth factor receptor 3 (sVEGFR-3) in plasma as pharmacodynamic biomarker

► sVEGFR-3 is a potential biomarker for the anti-angiogenic activity of tyrosine kinase inhibitors. ► An ELISA for the quantification of sVEGFR-3 in human plasma was successfully validated. ► The assay performance was confirmed in two clinical trials including healthy volunteers and cancer patients. ► The decrease of sVEGFR-3 levels after sunitinib intake was well described and occurs also in the absence of any tumor. ► With the assay validation and the characterization of sVEGFR-3 behavior in human plasma the first step in the biomarker validation process for sVEGFR-3 was achieved.