What are angiogenesis inhibitors and how do they work?

Angiogenesis inhibitors are specific cancer-fighting substances which block the growth of blood vessels that induce tumor growth, rather than blocking growth of tumor cells themselves. These inhibitors function in several ways. Some of the inhibitors are monoclonal antibodies which recognize and bind solely to VEGF. Once VEGF binds to the drugs, it is unable to activate the VEGF receptor. Bevacizumab is an example of a drug that binds to VEGF and stops its ability to activate receptors on endothelial cells. Other angiogenesis inhibitors bind to VEGF and/or its receptor in addition to other receptors on the surface of endothelial cells or to other proteins in downstream signaling pathways blocking their activity. These are specifically known as tyrosine kinase inhibitors. The drug sunitinib is one example of this type of inhibitor which stops VEGF receptors from sending signals to blood vessel cells. Some angiogenesis inhibitors are immunomodulatory drugs, which are substances that suppress or stimulate the immune system and also have anti angiogenic properties. Angiogenesis inhibitors for cancer can be prescribed by a doctor to take orally or intravenously. The goal of these agents is to prevent or slow down the growth of cancer by cutting off a tumor’s blood supply, they do not destroy the tumor itself. For this reason, these drugs are typically used in combination with chemotherapy or other treatment.