How do you weigh the risks of re-treatment with infliximab in a patient who has been off it for over a year?

To answer this question, we first need to go back in time. Treatment with infliximab has been known to elicit the formation of antibodies against infliximab. The presence of these antibodies has been associated with infusion reactions in 7-19 % of patients and may also shorten the duration of the effect of infliximab when given repeatedly. This observation was confirmed in a 2003 NEJM study by Baert et al. Patients who developed anti-infliximab antibodies were at higher risk for developing infusion reactions, and a reduced duration of response, to treatment with infliximab. Co-treatment with an immunosuppressive drug was found to suppress the antibody response and prolong the clinical response to infliximab. This study established the benef...

I am generally comfortable restarting infliximab therapy after a gap in time (assuming the reason for stopping in the first place was not lack of response) when the patient was taking concomitant immunomodulatory therapy during the first course, for the reasons Dr. @Dr. First Last outlined. When a patient has had prior treatment with infliximab monotherapy, I am much more cautious. In my experience, these patients are at higher risk for an infusion reaction at the start of the second course, presumably because they have developed antichimeric antibodies to the infliximab. In this case, when retreatment with infliximab is determined to be the most appropriate treatment, I would ensure that the patient is monitored closely during the first fe...