Comparison of outcomes after plasma therapy or eculizumab in pediatric patients with atypical hemolytic uremic syndrome

Background Atypical hemolytic uremic syndrome (aHUS) is an ultra-rare and life-threatening disease. For decades, plasma therapy was used to manage patients with aHUS. Since eculizumab, a recombinant humanized anti-C5 monoclonal antibody, was approved for treatment of aHUS, it has been used to treat patients with aHUS. Here, we examined the effectiveness of eculizumab and plasma therapy, respectively in the treatment of pediatric patients with aHUS. Methods Data were collected from questionnaires sent to 75 institutions known to be treating thrombotic microangiopathy (TMA). Results A total of 24 patients were evaluable, in which no recurrence of TMA was reported at last observation. There were four therapy groups: two patients receiving supportive therapy, one receiving plasma therapy alone, 17 switching from plasma therapy to eculizumab (therapy switched), and four receiving eculizumab alone. Among 17 patients of therapy-switched group, only one patient achieved complete remission at the end of plasma therapy, 15 patients achieved complete remission after eculizumab initiation, and two patients reached end-stage renal disease. Adverse events were reported in nine cases; among these, meningococcal infection, anaphylaxis, and eculizumab-related infusion reaction were reported among those treated with eculizumab. Conclusion This study provided substantial evidence from a Japanese population that the conversion from plasma therapy to eculizumab therapy should be considered in patients with aHUS who show an incomplete response to plasma therapy. In addition, although no new safety events were detected, careful attention should be paid to meningococcal infection, eculizumab-related infusion reactions and allergic reactions with administration of eculizumab.