KRAS and metastatic colorectal cancer: Regorafenib (Stivarga) is a novel oral multikinase inhibitor approved by the US Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer in patients previously treated with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, anti-VEGF therapy, and EGFR inhibitors (for patients with the wild-type KRAS gene).