Anti-Angiogenics: Current Situation and Future Perspectives

Angiogenesis, the process leading to the formation of new blood vessels, is one of the hallmarks of cancer. Extensive studies established that i) vascular endothelial growth factor (VEGF) is a key driver of sprouting angiogenesis, ii) VEGF is overexpressed in most solid cancers, and iii) inhibition of VEGF can suppress tumor growth in animal models. This has led to the development of pharmacological agents for anti-angiogenesis to disrupt the vascular supply and starve the tumor of nutrients and oxygen, primarily through the blockade of VEGF/VEGF receptor signaling. This effort has resulted in 11 anti-VEGF drugs approved for certain advanced cancers, either alone or in combination with chemotherapy and other targeted therapies. However, inhibition of VEGF signaling is not effective in all cancers, and anti-angiogenics have often only limited impact on overall survival of cancer patients. This review focuses on the current status of FDA-approved anti-angiogenic antibodies and tyrosine kinase inhibitors and summarizes the progress and future directions of VEGF-targeted therapy.