Strategy for bone marrow transplantation in eculizumab-treated paroxysmal nocturnal hemoglobinuria

Although the recent introduction of eculizumab has had a significant impact on the management of paroxysmal nocturnal hemoglobinuria (PNH), bone marrow transplantation (BMT) remains the only therapeutic option for patients who develop severe aplasia in the clinical course of PNH. However, information regarding BMT for eculizumab-treated PNH patients is scarce, and two major points—the optimal duration of eculizumab therapy, and the optimal BMT conditioning regimen—remain unclear. Here, we describe the clinical course of a PNH patient who was successfully treated with unrelated reduced-intensity BMT. Eculizumab was discontinued 2 weeks prior to the initiation of the conditioning regimen, which consisted of fludarabine 180 mg/m 2 , cyclophosphamide 100 mg/kg, rabbit anti-thymocyte globulin 2 mg/kg, and TBI 3 Gy. Complete donor chimerism was rapidly achieved in association with a rapid decrease in the proportion of PNH erythrocytes. The patient became transfusion-free immediately after BMT, and had no recurrence of hemolysis. The present case suggests that discontinuation of eculizumab before BMT and the use of a highly lymphoablative conditioning regimen may act as a successful treatment strategy in BMT for PNH. Further studies are warranted to evaluate the efficacy and safety of this treatment strategy.