A human monoclonal antibody directed against terminal complement protein C5. Eculizumab binds to terminal complement protein C5, thereby blocking C5 cleavage into pro-inflammatory components and blocking the complement-mediated destruction of paroxysmal nocturnal hemoglobinuria (PNH) red blood cells. Check for active clinical trialsusing this agent. OR A drug used to prevent red blood cells from being destroyed in patients with a rare red blood cell disorder called paroxysmal nocturnal hemoglobinuria (PNH). It is also used to treat another rare disorder called atypical hemolytic urea syndrome (aHUS), in which blood clots form in small blood vessels. Eculizumab binds to an immune system protein called C5. This helps keep red blood cells from breaking down and helps keep blood clots from forming. Eculizumab is a type of monoclonal antibody. Also called Soliris. OR A drug used to prevent red blood cells from being destroyed in patients with a rare red blood cell disorder called paroxysmal nocturnal hemoglobinuria (PNH). It is also used to treat another rare disorder called atypical hemolytic urea syndrome (aHUS), in which blood clots form in small blood vessels. Eculizumab binds to an immune system protein called C5. This helps keep red blood cells from breaking down and helps keep blood clots from forming. Eculizumab is a type of monoclonal antibody. Also called Soliris.