Paroxysmal Nocturnal Hemoglobinuria (PNH) is an ultra-rare and life-threatening disease resulting from the chronic hemolysis of a patient’s red blood cells (RBCs). PNH afflicts 1-2 people per million globally. A PNH patient’s immune system attacks their own RBCs because these cells lacks a key inhibitory protein that is normally found on their surface. This inhibitory protein prevents complement attack in healthy individuals. The chronic hemolysis that results causes serious health problems, including blood clots, organ failure, and death.