Regorafenib (BAY 73-4506) is an orally active and potent multi-targeted receptor tyrosine kinase inhibitor, with IC50 values of 13/4.2/46, 22, 7, 1.5 and 2.5 nM for VEGFR1/2/3, PDGFRβ, Kit, RET and Raf-1, respectively. Regorafenib shows very robust antitumor and antiangiogenic activity.