Used in the treatment of paroxysmal nocturnal hemoglobinuria (PNH), a rare blood disorder where uncontrolled complement activation destroys red blood cells. It prevents hemolysis by inhibiting the cleavage of complement protein C5, stopping the formation of the membrane attack complex. Also applied in atypical hemolytic uremic syndrome (aHUS) to protect against complement-mediated thrombotic microangiopathy. Due to its long half-life, it allows for less frequent dosing compared to other complement inhibitors, improving patient convenience and adherence. Employed in clinical settings requiring targeted complement suppression without broad immune compromise.