Immunogenicity of infliximab: how to handle the problem?

BACKGROUND The introduction of infliximab has greatly advanced the therapeutic armamentarium of the inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis. Although the benefit/risk ratio for infliximab is positive, of particular concern has been the problem of immunogenicity ascribed to the chimeric properties of the drug. Antibody formation is associated with allergic reactions and loss of response. AIMS AND METHODS A literature search was undertaken on the magnitude of the problem of immunogenicity and on the clinical consequences. A survey was conducted about the clinical practice and management of acute and delayed allergic reactions to infliximab in different centres in Belgium. For this, a questionnaire was sent to all members of the Belgian IBD research group (n = 38 belonging to 29 centers). RESULTS AND CONCLUSION Infusion reactions are important immunologic events induced by the presence of a substantial concentration of antibodies against infliximab (ATI) in the serum. Concomitant immunosuppressive treatment may optimize response to infliximab by preventing the formation of antibodies. Steroid administration prior to an infliximab infusion can further reduce the immunogenicity. Probably the most effective strategy to optimize treatment and avoid immunogenicity is maintenance therapy. If infliximab therapy can be discontinued is yet unclear but when treatment goals have been reached, we feel this should be attempted. In the case of relapse, infliximab should be restarted as maintenance long term. Practical guidelines on how to handle the problem of immunogenicity to infliximab are important for clinicians treating patients with IBD.