ActiveSite Pharmaceuticals utilizes proprietary lead discovery technology to discover new small molecule drug candidates for human diseases with unmet medical need. The company is initially focused on developing novel, innovative treatments for the major vision-threatening complication of diabetes, diabetic macular edema, and the genetic disease hereditary angioedema, by targeting the vascular protease plasma kallikrein, Kallikrein is a vascular serine protease, circulating in blood as an inactive zymogen, prekallikrein. Upon activation, plasma kallikrein cleaves its physiological substrate high molecular weight kininogen, generating the potent inflammatory vasodilator peptide bradykinin. Binding of bradykinin to its receptors on the surface of endothelial cells lining blood vessels initiates a series of signaling events leading to the opening of intercellular junctions between endothelial cells, resulting in increased vascular permeability.