Vascular Endothelial Growth Factor, or VEGF, is a protein growth factor which is required for formation of blood vessels, a process known as angiogenesis. According to Wikipedia:
In the adult human, angiogenesis is only consistently active in the gut - however in pathological cases such as cancer, where a solid tumor grows rapidly and therefore requires a blood supply, there is also active angiogenesis. Therefore, the blockade of VEGF is a potentially viable strategy for treating solid tumors.Regeneron has developed a chimeric (i.e., fusion) protein, which it refers to as VEGF Trap (aflibercept), that comprises the extra-cellular domain of VEGF Receptor (the growth factor's natural receptor). The extra-cellular domain of the receptor is used to bind, or "trap" VEGF, and thereby keep it from binding receptors on the surface of blood vessels. Regeneron is working towards FDA approval to market VEGF Trap for a number of ophthalmologic and oncology indications. According to the complaint, the company intends to submit a Biologic License Application before the end of the second quarter of 2011 to market the product for a wet age-related macular degeneration. Yesterday, Regeneron stock rose 19.7% after the company announced positive Phase 3 clinical trial results for the drug (see here).
Genentech has developed an antibody called Avastin that binds VEGF. Avastin is already approved for the treatment of colon cancer. The five Genentech patents which are the subject of the declaratory judgment action are directed toward chimeric VEGF receptor proteins capable of binding VEGF.