<p>Regorafenib is a kinase inhibitor and it inhibits multiple membrane-bound and intracellular kinases involved in normal cellular functions and in pathologic processes such as oncogenesis, tumor angiogenesis, and maintenance of the tumor microenvironment. Regorafenib or its major human active metabolites M-2 and M-5 inhibits the activity of RET, VEGFR1, VEGFR2, VEGFR3, KIT, PDGFR-alpha, PDGFR-beta, FGFR1, FGFR2, TIE2, DDR2, Trk2A, Eph2A, RAF-1, BRAF, BRAFV600E, SAPK2, PTK5, and Abl. Due to its inhibitory functions, regorafenib can inhibit the progression of certain solid tumors.</p>