Antiangiogen

Antiangiogen refers to antiangiogenic agents or strategies that inhibit angiogenesis, the growth of new blood vessels. In medicine, antiangiogenesis is used to limit blood supply to tumors and to treat diseases driven by abnormal vessel growth, such as certain retinal conditions. The concept originated from the observation that tumors require blood vessels to grow beyond a certain size, leading to the development of therapies that disrupt vascular formation.

Most antiangiogenic therapies target the vascular endothelial growth factor (VEGF) pathway or related signaling networks that promote endothelial proliferation and new vessel formation. Inhibition can occur at multiple levels, including neutralizing VEGF ligands, blocking VEGF receptors, or inhibiting downstream tyrosine kinase signaling. Other targets include fibroblast growth factor, platelet-derived growth factor, angiopoietins, and matrix metalloproteinases. Some approaches aim to normalize abnormal tumor vasculature to improve drug delivery and oxygenation rather than simply pruning vessels.

Major classes and examples include monoclonal antibodies against VEGF or VEGFR, soluble decoy receptors that trap VEGF, and small-molecule tyrosine kinase inhibitors. Notable agents include bevacizumab, ranibizumab, aflibercept, ramucirumab, and TKIs such as sunitinib, sorafenib, pazopanib, and axitinib. Other antiangiogenic strategies involve thalidomide derivatives and endostatin.

Applications span oncology, where antiangiogenics are used for several solid tumors, and ophthalmology, particularly age-related macular degeneration and other retinal neovascular diseases. Side effects may include hypertension, thrombosis, wound healing impairment, proteinuria, and hemorrhage. Limitations include resistance and tumor adaptation, necessitating combination approaches and biomarker-guided use. Ongoing research seeks to optimize regimens, dosing, and targets to expand efficacy and safety.