regorafenib + vincristine + irinotecan

This is a **combination chemotherapy regimen** consisting of **regorafenib**, **vincristine**, and **irinotecan**. \n- **Regorafenib** is a small-molecule multikinase inhibitor that blocks multiple protein kinases involved in tumor angiogenesis (e.g., VEGFR, TIE2), oncogenesis (e.g., KIT, RET, RAF), and the tumor microenvironment (e.g., PDGFR, FGFR, CSF1R)[1][5][3]. \n- **Irinotecan** is a topoisomerase I inhibitor; it acts by inhibiting DNA topoisomerase I, resulting in DNA damage and inhibition of cancer cell replication[2][4][6]. \n- **Vincristine** is a vinca alkaloid that inhibits microtubule formation in mitotic spindle, halting cell division at metaphase (mechanism not covered in above results, added from standard knowledge; see comments). \nThis combination is experimental and is not a standard or widely approved regimen. Each component is individually approved for several cancers, notably colorectal cancer (regorafenib, irinotecan), but the specific three-drug combination is not standard and may be investigated in clinical trials or specialized scenarios.