Efficacy of Eculizumab in a Patient with Paroxysmal Nocturnal Hemoglobinuria Requiring Transfusions 14 Years after a Diagnosis in Childhood

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired clonal disorder characterized by chronic complement-mediated hemolysis. The humanized anti-05 antibody eculizumab binds to the C5 protein and suppresses hemolysis by inhibiting C5b-9 generation. Here, we report on a 27-year-old woman who was found to have PNH in 1997 (at 13 years of age), without subsequent transfusions, thrombosis, or renal disorder. She had been experiencing frequent malaise and fatigue and was sometimes unable to participate in social activities. She had also experienced repeated hemolytic episodes due to infection, and the hemoglobin level had decreased from 7.0 to 5.0 g/dL several times since February 2010. Red blood cell transfusion was necessary, and 6 months later, treatment with eculizumab was started. The hemoglobin level stabilized, and the patient became transfusion-independent. Furthermore, the patient showed significant improvements in fatigue scale scores and quality of life. Six months after the start of eculizumab therapy, the percentage of PNH-type red blood cells was found to have increased from 82.0% (1.95 x 10(12) cells/L) to 89.1% (2.78 x 10(12) cells/L). Furthermore, during treatment with eculizumab, intravascular hemolysis occurred due to a viral infection accompanied by a high fever. We also observed a persistent elevation in reticulocytes and total bilirubin levels, as well as a persistent reduction in haptoglobin levels. Extravascular hemolytic findings were also observed. Because treatment with eculizumab was started at a young age (27 years) and will be continued for many years, careful observation of the patient is required. (J Nippon Med Sch 2013; 80: 155-159)