Eculizumab is a monoclonal antibody that specifically binds to complement protein C5 with high affinity, thereby inhibiting its cleavage to C5a and C5b and preventing the generation of the terminal complement complex C5b-9. By this mechanism, Eculizumab (Soliris®) inhibits terminal complement mediated intravascular hemolysis in paroxysmal nocturnal hemoglobinuria patients.