Combination Chemotherapy and Bevacizumab as First-Line Therapy in Treating Patients With Metastatic Colorectal Cancer

OBJECTIVES: Primary * To compare the progression-free survival of bevacizumab in combination with oxaliplatin, irinotecan hydrochloride, fluorouracil, and leucovorin calcium (FOLFOXIRI) versus bevacizumab in combination with irinotecan hydrochloride, fluorouracil, and leucovorin calcium (FOLFIRI) in patients with unresectable, metastatic colorectal cancer. Secondary * To evaluate the safety profile, including long-term adverse events of these regimens in these patients. * To compare the overall response rate, duration of response, and secondary R0 surgery rates of metastases and overall survival between treatment arms. * To evaluate potential surrogate markers predictive of bevacizumab activity. OUTLINE: This is a multicenter study. Patients are stratified according to ECOG performance status (0 vs 1-2), prior adjuvant chemotherapy (yes vs no), and participating center. Patients are randomized to 1 of 2 treatment arms. * Arm I (FOLFOXIRI): Patients receive irinotecan hydrochloride IV over 1 hour, oxaliplatin IV over 2 hours, leucovorin calcium IV over 2 hours, and bevacizumab IV on day 1. Patients also receive fluorouracil IV continuously over 48 hours beginning on day 1. * Arm II (FOLFIRI): Patients receive irinotecan hydrochloride IV over 1 hour, leucovorin calcium IV over 2 hours, and bevacizumab IV on day 1. Patients also receive fluorouracil IV continuously over 48 hours beginning on day 1. In both arms, treatment repeats every 2 weeks for up to 12 courses. Treatment with bevacizumab, fluorouracil, and leucovorin calcium continues in the absence of disease progression or unacceptable toxicity. Patients undergo serum extraction and blood sample collection periodically for genotyping studies. Patients also undergo collection of tumoral sections from paraffin embedded primary and/or metastatic lesions periodically for immunohistochemical analyses. After completion of study treatment, patients are followed every 8 weeks.