Bevacizumab in Combination With Chemotherapy: First-Line Treatment of Patients With Metastatic Colorectal Cancer

Bevacizumab, a monoclonal antibody to vascular endothelial growth factor, was approved in 2004 for use in combination with intravenous 5-fluorouracil-based chemotherapy for the treatment of metastatic colorectal cancer. Bevacizumab is the first approved agent that targets tumor angiogenesis. The pivotal phase III trial showed significantly greater overall and progression-free survival with the addition of bevacizumab to irinotecan, 5-fluorouracil, and leucovorin. These outcomes were observed irrespective of patients' pretreatment characteristics (age ≥65 years, ≥1 site of metastasis, or location of primary tumor). Furthermore, there was a significant survival benefit regardless of pretreatment biomarkers, including plasma vascular endothelial growth factor level, tumor thrombospondin and p53 expression, and mutational status in k-ras, b-raf, and p53. Analysis of data in responders and nonresponders showed a response-independent survival benefit, indicating that even those in whom there was not an objective tumor response by standard criteria benefited from the addition of bevacizumab. Preliminary data on the addition of bevacizumab to oxaliplatin- and capecitabine-based regimens for the first-line treatment of metastatic colorectal cancer show that these regimens are well tolerated, with consistent increases in objective response rates, time to progression, and overall survival. The survival advantages in patients with metastatic colorectal cancer with the addition of bevacizumab to chemotherapy support the use of this agent in first-line treatment.