Ramucirumab, a fully human IgG1 monoclonal antibody and a direct VEGFR2 antagonist, binds with high affinity to the extracellular domain of VEGFR2 and block the binding of natural VEGFR ligands (VEGF-A, VEGF-C and VEGF-D). These ligands are secreted by solid tumors to promote angiogenesis (formation of new blood vessels from pre-existing ones) and enhance tumor blood supply. Binding of ramucirumab to VEGFR2 leads to inhibition of VEGF-mediated tumor angiogenesis.Kinase insert domain receptor (KDR, a type IV receptor tyrosine kinase, CD309, cluster of differentiation 309, Flk1, Fetal Liver Kinase 1) is the human gene encoding vascular endothelial growth factor receptor 2 (VEGFR-2), which is a VEGF receptor. The Q472H germline KDR genetic variant affects VEGFR-2 phosphorylation and has been found to associate with microvessel density in NSCLC.
