A first-line chemotherapy regimen consisting of folinic acid (leucovorin), fluorouracil, irinotecan and bevacizumab used for the treatment of advanced-stage colorectal cancer. Or A chemotherapy combination used as an initial treatment of colorectal cancer that has spread. It includes the drugs leucovorin (folinic acid), fluorouracil, irinotecan hydrochloride, and bevacizumab. Also called FOLFIRI-Avastin regimen and FOLFIRI-bevacizumab.