Bevacizumab in the treatment of colorectal cancer

Bevacizumab is a humanised monoclonal antibody that inhibits vascular endothelial growth factor (VEGF), the key mediator of tumour angiogenesis, and has been shown to improve survival when given with chemotherapy to patients with metastatic colorectal cancer. In a pivotal Phase III clinical trial, 813 subjects were treated with irinotecan, 5-fluorouracil (5-FU) and leucovorin and randomised to receive placebo or bevacizumab. Median survival for the group receiving bevacizumab was increased by 30%, from 15.6 to 20.3 months (p < or = 001). Other Phase II and III studies in colorectal cancer have demonstrated a benefit when bevacizumab is added to regimens of 5-FU and leucovorin, and 5-FU, leucovorin and oxaliplatin. The toxicity associated with bevacizumab is generally mild, consisting of manageable hypertension, clinically insignificant proteinuria and mild mucosal bleeding. Infrequent severe toxicities have been reported, consisting of arterial thrombosis and gastrointestinal perforations (1.5%). Bevacizumab represents the first angiogenesis modulator that has a proven benefit in cancer therapy.