Targeted pharmacotherapy of retinal diseases with ranibizumab

Diseases of retinal and/or choroidal blood vessels are the most prevalent causes of moderate and severe vision loss in developed countries. Vascular endothelial growth factor (VEGF)-A plays a critical role in the pathogenesis of many of these diseases. Ranibizumab is a humanized antigen-binding fragment that binds all isoforms of VEGF-A. Intraocular injections of ranibizumab cause significant visual improvement in approximately 40% of patients with choroidal neovascularization due to age-related macular degeneration (AMD). Pilot trials have indicated that intraocular injections of ranibizumab also provide benefits in patients with macular edema due to diabetic retinopathy or retinal vein occlusions. Based upon several case series, bevacizumab, a full-length humanized monoclonal antibody that binds all isoforms of VEGF-A, improves vision in patients with choroidal neovascularization due to AMD and other diseases. Case series also suggest that bevacizumab can cause regression of retinal neovascularization in patients with proliferative diabetic retinopathy. Taken together, results with ranibizumab and bevacizumab suggest that potent antagonists of VEGF will provide the foundation of treatment for a wide variety of diseases complicated by retinal or choroidal neovascularization, or by excessive vascular leakage leading to macular edema.