BACKGROUND: The combination of bevacizumab and bolus 5-fluorouracil, leucovorin and irinotecan is highly effective in patients with metastatic colorectal cancer (mCRC). This randomised, multicenter, non-comparative phase II trial assessed the efficacy and safety of bevacizumab plus oral capecitabine plus irinotecan (XELIRI) or infusional 5-fluorouracil, leucovorin plus irinotecan (FOLFIRI) as first-line therapy for patients with mCRC. PATIENTS AND METHODS: Patients received bevacizumab 7.5mg/kg on day 1 plus XELIRI (irinotecan 200mg/m(2) on day 1 and oral capecitabine 1,000 mg/m(2) bid on days 1-14) every 3 weeks or bevacizumab 5mg/kg on day 1 plus FOLFIRI (5-fluorouracil 400mg/m(2) on day 1 plus 2,400 mg/m(2) as a 46-h infusion, leucovorin 400mg/m(2) on day 1, and irinotecan 180 mg/m(2) on day 1) every 2 weeks. Patients aged ≥ 65 years received a lower dose of capecitabine (800 mg/m(2) twice daily). The primary endpoint was 6-month progression-free survival (PFS) rate. RESULTS: A total of 145 patients were enrolled (bevacizumab-XELIRI, n=72; bevacizumab-FOLFIRI, n=73). The 6-month PFS rate was 82% (95% confidence intervals (CI) 71-90%) in the bevacizumab-XELIRI arm and 85% (95% CI 75-92%) in the bevacizumab-FOLFIRI arm. In both the bevacizumab-XELIRI and bevacizumab-FOLFIRI arms, median PFS and overall survival (OS) were 9 and 23 months, respectively. The most frequent toxicities were grade 3/4 neutropenia (bevacizumab-XELIRI 18%; bevacizumab-FOLFIRI 26%) and grade 3 diarrhoea (12% and 5%, respectively). CONCLUSIONS: This randomised non-comparative study demonstrates that bevacizumab-XELIRI and bevacizumab-FOLFIRI are effective regimens for the first-line treatment of patients with mCRC with manageable toxicity profiles.