Treatment with infliximab, a chimeric monoclonal IgG1 antibody against tumor necrosis factor, can result in the formation of antibodies against infliximab.
In this study, researchers from Belgium evaluated the clinical significance of these antibodies in patients with Crohn's disease.
The research team assessed 125 consecutive patients with Crohn's disease who were treated with infliximab infusions.
They evaluated the concentrations of infliximab and of antibodies against infliximab, clinical data, and side effects. They also considered the use of concomitant medications both before and 4, 8, and 12 weeks after each infusion.
The research team found that a mean of 3.9 infusions per patient were administered over a mean period of 10 months.
|Antibodies against infliximab were detected in 61% of patients.|
|New England Journal of Medicine|
The team detected antibodies against infliximab in 61% of patients.
Antibody concentrations of 8 µg per ml or greater before an infusion predicted a shorter duration of response, as well as a higher risk of infusion reactions.
In addition, infliximab concentrations were significantly lower at 4 weeks in patients who had had an infusion reaction, compared with patients who had never had an infusion reaction.
The team found that patients who had infusion reactions had a median response duration of 38.5 days, compared with 65 days in patients who did not have an infusion reaction.
However, concomitant immunosuppressive therapy was found to be predictive of low titers of antibodies against infliximab, and high concentrations of infliximab 4 weeks after an infusion.
Dr Filip Baert's team concluded, "The development of antibodies against infliximab is associated with an increased risk of infusion reactions and a reduced duration of response to treatment".
"Concomitant immunosuppressive therapy reduces the magnitude of the immunogenic response."