An overview of clinical trials involving inhibitors of angiogenesis and their mechanism of action.

Angiogenesis is a biologic process whereby endothelial cells divide and migrate to form new blood vessels. This process is required in physiological conditions, but is also a necessary requirement for solid tumors to grow and metastasize. Over the last several years, the growth factors that have both a positive and negative influence on tumor angiogenesis have been delineated. Interfering with tumor angiogenesis was considered a potential therapeutic strategy 25 years ago, but only recently have compounds with an ability to interfere with angiogenesis entered clinical trials. This review will discuss the first generation of angiogenesis inhibitors, their mechanism of action and data from clinical trials.