noun: (pharmacology) An anticancer drug that is a genetically engineered monoclonal antibody administered intravenously to slow or inhibit tumor growth especially in some metastatic forms of cancer (such as colorectal cancer). It acts by binding to and inhibiting the activity of vascular endothelial growth factor, a protein that promotes the growth of new blood vessels which supply a spreading tumor. It is marketed under the trademark Avastin.
