Regorafenib potently inhibits VEGFR2 autophosphorylation in NIH-3T3/VEGFR2 cells with an IC50 of 3 nM. In HAoSMCs, regorafenib inhibits PDGFR-β autophosphorylation after stimulation with PDGF-BB, with an IC50 of 90 nM. Regorafenib inhibits the proliferation of VEGF165-stimulated HUVECs, with an IC50 of 3 nM. Regorafenib causes a concentration-dependent decrease in Hep3B cell growth, having an IC50 of 5 μM. Regorafenib subsequently increases the levels of phospho-c-Jun, a JNK target, but not total c-Jun in Hep3B cells.