PURPOSE: In a phase III trial, combining bevacizumab (BV)--a recombinant, humanized, monoclonal antibody targeting vascular endothelial growth factor--with irinotecan, bolus fluorouracil (FU), and leucovorin (LV; IFL) increased survival compared with IFL alone in first-line treatment of patients with metastatic colorectal cancer (CRC). Results for the parent study of IFL/BV versus IFL/placebo are reported elsewhere. Here, we describe efficacy and safety results for the third patient cohort in this trial, who received BV combined with FU/LV, and compare them with results for concurrently enrolled patients who received IFL. METHODS: Patients (N = 923) were randomly assigned to receive IFL/placebo (control), IFL/BV, or FU/LV/BV. Bevacizumab (Avastin; Genentech Inc, South San Francisco, CA) 5 mg/kg was administered intravenously every 2 weeks. Before an interim analysis confirmed acceptable safety for IFL/BV, 313 patients were concurrently randomly assigned to these three arms; after this analysis, the FU/LV/BV arm was discontinued. RESULTS: Median overall survivals were 18.3 and 15.1 months with FU/LV/BV (n = 110) and IFL/placebo (n = 100), respectively. Median progression-free survivals were 8.8 and 6.8 months, respectively. Overall response rates were 40.0% and 37.0%, and median response durations were 8.5 and 7.2 months, respectively. Adverse events consistent with those expected from FU/leucovorin- or IFL-based regimens were seen, as were modest increases in hypertension and bleeding in the bevacizumab arm, which were generally easily managed. CONCLUSION: The FU/LV/BV regimen seems as effective as IFL and has an acceptable safety profile. FU/LV/BV is an active alternative treatment regimen for patients with previously untreated metastatic CRC.