#92: What Is the Optimal Management of Patients Immunosuppressed with the Anti-compliment Monoclonal Antibody, Eculizumab? A Case Report and Review
Authors: Tinoco I , Jarrell A , Correa L , Bissler J , DeVincenzo J , Tinoco Ivan , Jarrell Amber , Correa Lauren , Bissler John J , DeVincenzo John P 
Published: March 2021

Abstract

Background
Patients with deficiencies of terminal components of complement are at hundreds to thousands fold increased risk of severe and fatal Neisseria spp. infections compared with the general population. Eculizumab is a newly approved monoclonal antibody C5 complement inhibitor. It is indicated for the treatment of atypical hemolytic uremic syndrome (atypical HUS), myasthenia gravis, and paroxysmal nocturnal hemoglobinuria. Because of the complement-depleting effect of Eculizumab dosing (Soliris®, Alexion Pharmaceuticals, Munich, Germany), patients are immunosuppressed for specific infectious pathogens (including Neisseria species) against which protection partially relies on normal complement activity. Because Eculizumab treatment is associated with a dramatically increased risk of Neisseria species. infections, recommendations for Neisseria meningitidis vaccination and antibiotic prophylaxis are contained in Eculizumab prescribing information. However, the most appropriate prevention of infections after Eculizumab has yet to be determined.

Methods
Case report and literature review.

Results
A previously healthy 7-year-old male was diagnosed with atypical HUS which included renal failure progressing to dialysis, persistent thrombocytopenia, hemolytic anemia, and hemoglobinuria. Stool cultures and a stool multiplex PCR panel did not detect Shiga-like producing E. coli nor E. coli O157/H7. Eculizumab dosing was therefore planned and Infectious Diseases consultation was obtained for appropriate preventions. The FDA Prescribing Information recommends Neisseria meningitidis vaccination before starting Eculizumab or, if immediate Eculizumab is necessary, to use antibiotic prophylaxis until 2 weeks after vaccination. The accepted protective titer after meningococcal vaccination is population based and uses the serum bactericidal assay (SBA). An antibody titer of &gt;1:4 (human compliment) or 1:8 (rabbit complement) is considered protective. However, this “gold standard” assay incorporates the use of exogenous human or rabbit complement. The protective SBA titers in subjects with terminal complement component deficiencies may not be properly assessed using these same SBA titer protective thresholds. Furthermore, serious meningococcal infections have occurred after appropriate vaccination in patients receiving chronic Eculizumab treatments (ie for paroxysmal nocturnal hemoglobinuria). Finally, SBA protective levels after single Neisseria meningitidis vaccination have not been achieved in majorities of patients with renal failure receiving dialysis and or transplant immunosuppression.

Conclusions
The current Eculizumab prescribing information recommendations for vaccination and antimicrobial prophylaxis may be inadequate to prevent serious Neisseria infections. Repeated Neisseria meningitidis vaccination and extended antibiotic prophylaxis may afford better protection in patients chronically dosed with Eculizumab.