What is angiogenesis?
Angiogenesis is the formation of new blood vessels. The process is controlled by certain chemicals produced in the body. The word comes from 2 Greek words, angio meaning blood vessel and genesis meaning beginning. Although this may help in normal wound healing, cancer can grow when these new blood vessels are created. New blood vessels near the cancer cells provide them with oxygen and nutrients. This allows the cancer cells to multiply, invade nearby tissue, and spread to other areas of the body (metastasize).
What are angiogenesis inhibitors and how do they work?
A chemical that interferes with the signals to form new blood vessels is referred to as an angiogenesis inhibitor. Scientists have studied the effect of angiogenesis inhibitors on certain kinds of tumors and cells.
Sometimes called antiangiogenic therapy, this treatment may prevent the growth of cancer by blocking the formation of new blood vessels. Angiogenesis inhibitor therapy may stabilize the tumor and prevent it from growing further, or reduce the size of the tumor. More than a dozen drugs with antiangiogenic properties are available in the U.S.
Some other cancer drugs are known to act in similar ways. Thalidomide (Thalomid) and lenalidomide (Revlimid) have been identified as having mild activity as angiogenesis inhibitors.
An angiogenesis inhibitor medication, bevacizumab (Avastin), has been approved by the FDA to aid in the treatment of glioblastoma, colorectal cancer, non-small cell lung cancer, and metastatic renal cell cancer. Other antiangiogenesis therapies include sunitinib, sorafenib, pazopanib, and everolimus. Many other angiogenesis inhibitors are now being studied as well.
Angiogenesis inhibitors have different side effects from most conventional cancer chemotherapy medications because they work very differently. Rather than killing healthy cells along with cancer cells, as many chemotherapy drugs do, angiogenesis inhibitors only prevent new blood vessels from forming. Though the side effects are generally less and milder than with conventional chemotherapy medications, some of the side effects can be serious and include high blood pressure, intestinal bleeding, clots in the arteries (which may lead to stroke or heart attack), and poor wound healing. Angiogenesis inhibitors might also affect a developing fetus and are not recommended for pregnant women or women who may become pregnant.