Eculizumab (Soliris) for paroxysmal nocturnal hemoglobinuria (PNH)

FDA recently (March 19) approved Eculizumab - a humanized monoclonal antibody with long-acting C5 terminal complement inhibitor property. It is a new class in immunotherapy selectively blocking terminal complement activation - one of the main component of innate immune system. Patients with PNH are hypersensitive to complement mediated intravascular hemolysis as their RBCs lacks complement-regulating surface proteins, i.e. decay-accelerating factor (DAF) or CD55, homologous restriction factor (HRF) or C8 binding protein, and membrane inhibitor of reactive lysis (MIRL) or CD59. However, Soliris helps only in preventing complement mediated hemolysis and decreasing need for excess blood transfusions but it does not alter the course of PNH as well as potential risks of thrombosis and aplastic anemia associated with PNH. A boxed warning showing risk for serious meningococcal infection and need for meningococcal vaccination is affixed following results of clinical trials.

Reference:
1. FDA Okays Eculizumab (Soliris) for Paroxysmal Nocturnal Hemoglobinuria - MedPage Today
2. Hilmen P et al. | Effect of Eculizumab on Hemolysis and Transfusion Requirements in Patients with Paroxysmal Nocturnal Hemoglobinuria | N Engl J Med 2004;350:552-559
3. eMedicine.com article on PNH
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