Time to antibody detection and associated factors for presence of anti-drug antibodies in pediatric inflammatory bowel disease patients treated with anti-TNF therapy.

Background: Loss of response in pediatric inflammatory bowel disease patients treated with biologic medications can be due to development of anti-drug antibodies. Natural history of anti-drug antibodies development has not been well described in pediatric inflammatory bowel disease. The primary aim of this study was to describe a single-center experience for the temporal onset of anti-drug antibodies detection.

Methods: We performed a retrospective, single-center chart review of pediatric inflammatory bowel disease patients at the Division of Pediatric Gastroenterology, Hepatology, and Nutrition at Rainbow Babies and Children's Hospital from 2010 to 2015. Patients were treated with infliximab or adalimumab and had at least two evaluations for anti-drug antibodies with the homogenous mobility shift assay. Demographics, laboratory and medication data, and clinical disease activity were collected.

Results: A total of 75 subjects are included in the analysis. Eighty-one percent of subjects were treated with infliximab. Eleven subjects developed anti-drug antibodies; average time to anti-drug antibodies detection was 13.2 ± 7.3 months. Longer duration of inflammatory bowel disease, L1 location in Crohn's disease, and not having immunomodulatory therapy before biologic was associated with higher risk of antibody detection. Antibody detection occurred more frequently with infliximab vs. adalimumab. Time-to-antibody detection for infliximab and adalimumab was 14.83 and 23.48 months, respectively.

Conclusion: Chances of anti-drug antibodies detection in the infliximab group were higher than the adalimumab group. Time-to-antibody detection was 8.65 months longer in patients who received adalimumab when compared to infliximab. These results may have implications for long-term therapy and help guide use of concomitant immunomodulators.