Vascular endothelial growth factor receptor 2 (VEGFR2, also known as KDR and FLK1) is a receptor tyrosine kinase that regulates angiogenesis, vascular development, and embryonic hematopoiesis in response to VEGF isoforms A, C, and D. VEGFR2 kinase inhibitor II is a reversible, cell-permeable inhibitor of VEGFR2's kinase activity (IC50 = 70 nM). It less potently inhibits the platelet-derived growth factor receptor β (PDGFRβ; IC50 = 920 nM) and related receptor and non-receptor tyrosine kinases. VEGFR2 kinase inhibitor II blocks the growth of human umbilical vein endothelial cells stimulated with either VEGF or PDGF (IC50s = 110 nM and 2 μM, respectively).
LY2457546 is a potent and orally bioavailable inhibitor of multiple receptor tyrosine kinases involved in angiogenic and tumorigenic signalling. LY2457546 demonstrates potent activity against targets that include VEGFR2 (KDR), PDGFRβ, FLT-3, Tie-2 and members of the Eph family of receptors. In vivo, LY2457546 inhibited VEGF-driven autophosphorylation of lung KDR in the mouse and rat in a dose and concentration dependent manner. LY2457546 was well tolerated and exhibited efficacy in a 13762 syngeneic rat mammary tumor models. Additionally, LY2457546 caused complete regression of well-established tumors in an acute myelogenous leukemia (AML) FLT3-ITD mutant xenograft tumor model. The unique spectrum of target activity, potent in vivo anti-tumor efficacy in a variety of rodent and human solid tumor models, exquisite potency against a clinically relevant model of AML, and non-clinical safety profile justify the advancement of LY2457546 into clinical testing. (source: Invest New D......