Practical issues in using eculizumab for children with atypical hemolytic uremic syndrome in the acute phase: a review of 4 patients

Aim Recently eculizumab, a monoclonal antibody to C5, was found to improve the disease course of atypical hemolytic uremic syndrome (aHUS) and has been recommended as the first line treatment by an international consensus guideline. However, several practical issues in the use of eculizumab for the acute phase of aHUS have yet to be resolved. Methods Children who received eculizumab with diagnosis of aHUS between March 2010 and December 2015 at Tokyo Metropolitan Children's Medical Center were enrolled. aHUS was diagnosed according to the hemolytic uremic syndrome (HUS) criteria after excluding Shiga toxin-inducing Escherichia coli (STEC) -associated HUS and thrombocytopenic purpura. We retrieved and analyzed data from the electronic medical records at our institution. Results We reviewed 4 patients with suspected aHUS. Eculizumab was discontinued in 1 patient in whom STEC-HUS was later diagnosed. Treatment was continued in the remaining 3 patients without recurrence. Practical issues included difficulty in diagnosing aHUS, particularly in the acute phase, risk of infection by encapsulated organisms, especially Neisseria meningitis, and infusion reaction. In addition to issues relating to the acute phase, discontinuing eculizumab in stable patients in the chronic phase must be considered. Conclusion Eculizumab, the first line treatment for children with aHUS, is usually effective. However, certain problems associated with its use require caution to be exercised. As clinical information on eculizumab are still very limited, and the rationale for its long-term use has yet to be established, physicians are advised to exercise care when using eculizumab to manage aHUS.