Hereditary angioedema (HAE) agents treat and/or prevent HAE attacks. HAE is a rare genetic condition that occurs in people with low levels of a certain protein in their bodies called C1-INH (C1 esterase inhibitor); or in some cases, nonfunctional C1-INH. C1-INH helps regulate several cascade systems within our body, such as the complement system, the intrinsic coagulation system and the coagulation cascade (the process that causes our blood to clot), and the fibrinolytic system (the process that removes and degrades clots after blood vessels are repaired). It also helps control bradykinin production (bradykinin is a protein fragment that increases the movement of fluid through blood vessel walls, resulting in swelling and inflammation).
  During an attack, levels of C1-INH become so low that angioedema (severe swelling in the limbs, face, intestinal tract, and airway) occurs. HAE agents that treat or prevent HAE attacks add working C1-INH to the plasma, which brings levels of C1 bac...