Used to treat rare blood disorders such as paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS). It works by blocking the complement system, part of the immune system, to prevent destruction of red blood cells. Also used in generalized myasthenia gravis and neuromyelitis optica spectrum disorder where the immune system attacks nerve cells. Helps reduce symptoms, prevent complications, and improve quality of life in affected patients. Administered through intravenous infusion under medical supervision.