Ecallantide - Plasma kallikrein inhibitor, treatment of hereditary angioedema

C1 esterase inhibitor (C1-INH) activity is reduced in the blood of patients with hereditary angioedema (HAE) and is depleted in patients undergoing cardiopulmonary bypass surgery (CPB). The effect of this insufficiency is activation of the complement system, leading to inflammatory responses, and activation of the kallikrein-kinin system, leading to the swelling and pain associated with acute HAE attacks. Depleted C1-INH and elevated kallikrein are also believed to lie behind the inflammatory injuries and high blood loss associated with CPB surgery. Ecallantide is a recombinant protein inhibitor of kallikrein that is under development for the treatment of acute HAE attacks and to reduce blood loss in patients undergoing CPB surgery.