Safety and efficacy of eculizumab in paroxysmal nocturnal hemoglobinuria evolving from patients with myelodysplastic syndrome and aplastic anemia

7033 Background: Myelodysplastic syndrome (MDS) and aplastic anemia (AA) have been reported to be associated with the development of the acquired clonal hemolytic and bone marrow failure disorder, paroxysmal nocturnal hemoglobinuria (PNH). Two recent phase 3 clinical studies have demonstrated significant benefit of the complement inhibitor eculizumab (Soliris) in a heterogeneous population of patients with PNH (n=140). Methods: To investigate whether eculizumab was safe and effective in PNH patients with a history of MDS or AA (n=37), efficacy parameters were examined in the MDS/AA patient subpopulation. Results: Intravascular hemolysis, as assessed by plasma levels of the enzyme lactate dehydrogenase (LDH), was reduced from a mean of 1871 ± 159 U/L at baseline to 300 ± 21 U/L at week 26 in patients with a history of MDS or AA (p<0.001, signed rank test; normal range 103–223 U/L). Anemia was improved as packed RBC transfusion requirements were substantially reduced with eculizumab in these patients from a...