P444 Fecal calprotectin response to anti-tumor necrosis factor alpha induction and maintenance in Pediatric Inflammatory Bowel Disease

Abstract

Background Fecal calprotectin (FC) is a sensitive surrogate marker of mucosal inflammation in inflammatory bowel disease (IBD). Our aim was to asses the effect of anti-tumor necrosis factor alpha (TNFα) induction and maintenance therapy on FC levels in children with IBD. Methods The medical records of pediatric patients with IBD who were treated with anti-TNFα agents from 2015 to 2020 were reviewed retrospectively. We identified 63 patients who had FC levels measured prior to anti TNFα induction with sequential measurements during the first months of therapy. The main outcome measures were time to FC response according to cut-offs of 250,150,100 and 50µgr/gr. Variables affecting FC response were analyzed using multivariate analysis. Results Out of 63 patients, mean age 13.6 (±3) years, females 28(44.4%),54 (85.7%) had Crohn’s disease. The median (interquartile range) FC at baseline was 715 µgr/gr (312–1700). The outcomes of <250, <150, <100 and <50 µgr/gr were achieved by 52 (82%), 51 (81%), 44 (70%) and 32 (50%) patients, respectively. The mean time (± standard error) for achieving these cut-offs were 4.8 ±0.8, 7.9±1.3, 10±1.8 and 18.5±7.2 months, respectively. There was no statistically significant correlation between age, gender, type of disease, Paris classification, extra-intestinal manifestation, albumin levels, erythrocyte sedimentation rate, C-reactive protein and the pediatric disease activity indexes at baseline and FC response. Furthermore, there was no statistically significant correlation between anti TNFα trough concentration during induction and FC response. Conclusion In pediatric patients with IBD, FC response (<250µgr/gr) was achieved by the majority of patients within a relatively short period of time. Nevertheless, calprotectin normalization (<100µgr/gr) required an average period of approximately one year in responders.