BACKGROUND: This study was designed to determine the efficacy and tolerability of a novel 2-week regimen of capecitabine, oxaliplatin (OHP), and bevacizumab in patients with chemo-naive advanced colorectal cancer. PATIENTS AND METHODS: Nineteen patients with previously untreated advanced colorectal cancer received capecitabine at 1000 mg/m(2) twice a day on days 1-5 and days 8-12 of a 14-day cycle, and OHP at 85 mg/m(2) and bevacizumab at 10 mg/kg every 2 weeks. Because of unacceptable toxicities, the capecitabine dose was reduced to 850 mg/m(2). Thirty-one additional patients were treated at the lower capecitabine dose. Treatment continued until disease progression, persistent intolerable toxicity, or physician and/or patient discretion. RESULTS: Overall, toxicities were better managed and tolerated at the 850 mg/-m(2) capecitabine dose. The most common treatment-related grade ≥ 3 toxicities were diarrhea and sensory neuropathy. In the first 19 subjects, the response rate was 63% (95% confidence interval [CI], 38%-84%) and 5 patients had stable disease; median progression-free survival (PFS) was 10.1 months (95% CI, 5.7-19.5 months). In the subsequent 31 patients, the response was 42% (95% CI, 25%-61%); 11 patients had stable disease and median PFS was 10.4 months (95% CI, 6.9-15.4); median overall survival was 24.8 months (95% CI, 12.9-39.7). CONCLUSIONS: This novel regimen of capecitabine at 850 mg/m(2) twice a day on days 1-5 and days 8-12 and OHP at 85 mg/m(2)and bevacizumab at 10 mg/kg every 14 days is clinically active in advanced colorectal cancer. The toxicity profile of this regimen is consistent with the standard every-3-week dosing schedule.