This activity explores how current and emerging agents for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) target the complement system cascade. Follow along with the faculty as they explore the role of the complement system cascade in PNH disease pathogenesis, and address how emerging agents that build upon the current standards of care – including C5, C3 and factor B inhibitors – have potential to improve outcomes for patients with this disease. A case study is included to help demonstrate the importance of optimizing treatment in PNH and to explore the clinical circumstances in which switching treatment regimens may be indicated.