Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired, rare, chronic, and potentially life-threatening blood disease that is associated with persistently low hemoglobin levels, thrombosis, and debilitating symptoms. PNH can appear at any age and in any race or gender, and it is most often diagnosed in people in their early 30s. ¹

In PNH, blood cells lack complement regulatory proteins, so the body recognizes these healthy red blood cells as damaged. This leads to uncontrolled activation of the complement cascade, initiated at C3, and results in the destruction of oxygen-carrying red blood cells (hemolysis).² Hemolysis occurs in PNH through two mechanisms: intravascular hemolysis (IVH), which occurs inside blood vessels, and extravascular hemolysis (EVH), which occurs in the liver and spleen.

Biogen has a longstanding commitment to advancing care for people living with rare diseases, focusing our research on addressing areas with significant unmet need. Building on our expertise in rare disease, we are continuing our work to understand and provide support for people living with PNH.