Therapeutic targeting of tumor angiogenesis: how far have we come?

Author(s): Bruce C Baguley & Mark J McKeage

Angiogenesis, the formation of new blood vessels from existing ones, is a potentially important therapeutic target. The discovery of the role of VEGF in angiogenesis prompted research on two major classes of antiangiogenic drugs: those acting through VEGF itself and those acting on VEGF receptors. Combination trials, particularly with cytotoxic drugs, followed single-agent clinical trials in several cancer types including colorectal, breast and non-small-cell lung cancer. Positive findings of tumor responses were balanced by later analyses showing in many trials that overall survival was not significantly increased. The challenge for the future is to identify appropriate biomarkers that will allow patient selection for optimal therapy.