Bevacizumab works by blocking a protein called VEGF, which some cancer cells produce in large amounts. Blocking VEGF may prevent the growth of new blood vessels that tumors need to grow. Bevacizumab is a type of targeted therapy called an angiogenesis inhibitor. For cancer, it is given by slow injection into a vein (intravenous) and used for colon cancer, lung cancer, glioblastoma, and renal-cell carcinoma. In many of these diseases it is used as a first-line therapy. For age-related macular degeneration it is given by injection into the eye (intravitreal).