Bevacizumab (rHumAb VEGF; Genentech, Inc., CA), a recombinant humanized monoclonal antibody directed to VEGF, and neutralizes the biological properties of human VEGF. Bevacizumab, derived from the murine antibody A.4.6.1, comprises 93% human IgG frameworks and 7% murine-derived antigen-binding regions, the humanization providing a longer half-life and less immunogenicity.