VEGFA and age-related macular degeneration: Pegaptanib sodium (Macugen), first approved in the United States for the treatment of neovascular AMD in 2004, is a 28-base ribonucleic acid aptamer covalently linked to two branched 20-kD polyethylene glycol moieties, that was developed to bind and block the activity of extracellular VEGF, specifically at the 165-amino-acid isoform (VEGF165).