Phase I/II Study of Capecitabine Plus Oxaliplatin (XELOX) Plus Bevacizumab As First-line Therapy in Japanese Patients with Metastatic Colorectal Cancer

The addition of bevacizumab to fluoropyrimidine-based combination chemotherapy as first-line therapy for metastatic colorectal cancer results in clinically significant improvements in patient outcome. However, clinical trials have been conducted primarily in Caucasian patients with only a small proportion of Asian patients. This Phase I/II study was designed to evaluate the efficacy and safety of XELOX (capecitabine plus oxaliplatin) plus bevacizumab in Japanese patients with metastatic colorectal cancer. Patients with previously untreated, measurable metastatic colorectal cancer received bevacizumab 7.5 mg/kg and oxaliplatin 130 mg/m(2) on day 1, plus capecitabine 1000 mg/m(2) twice daily on days 1-14, every 3 weeks. A three-step design evaluated in: step 1, initial safety of XELOX in six patients; step 2, initial safety of XELOX plus bevacizumab in six patients; and step 3, efficacy and safety in a further 48 patients. The primary study endpoints were safety and response rate. No dose-limiting toxicity occurred during Steps 1 and 2. Fifty-eight patients were enrolled in Steps 2 and 3 and received XELOX plus bevacizumab. In the 57 patients assessed for response, the overall response rate was 72% (95% confidence interval, 58.5-83.0). Median progression-free survival was 11.0 months (95% confidence interval, 9.6-12.5) and median overall survival was 27.4 months (95% confidence interval, 22.0-not calculated). Eight patients (14%) underwent surgery with curative intent. The most common grade 3/4 adverse events were neurosensory toxicity (17%) and neutropenia (16%). XELOX plus bevacizumab is effective and has a manageable tolerability profile when given to Japanese patients with metastatic colorectal cancer.