Ranibizumab is a recombinant, humanized, Fab fragment of a mouse monoclonal antibody targeted against VEGF. As VEGF binds to cellular receptors, it stimulates angiogenesis and vascular leakage. Blockade of VEGF by ranibizumab leads to reduced stimulation of cell proliferation and permeability resulting in inhibition of angiogenesis and decreased leakage. Ranibizumab intravitreal administration in neovascular AMD patients has been shown to effectively reduce vascular leakage and growth of CNV and to stabilize or improve visual function.