Pediatric inflammatory bowel disease: Fecal calprotectin response to Anti-tumor necrosis factor alpha

Background Fecal calprotectin (FC) is a marker of mucosal inflammation in inflammatory bowel disease (IBD). We aimed to assess the effect of anti-tumor necrosis factor alpha (TNF alpha) therapy on FC levels in children with IBD. Methods The medical records of pediatric patients treated with anti-TNF alpha agents (2015-2020) were reviewed retrospectively. 63 patients had FC levels measured prior to anti TNF alpha induction with sequential measurements during follow-up. The main outcome measures were time to FC response according to cutoffs of 250, 150, 100 and 50 mu gr/gr. Results Mean age was 13.6 +/- 3 years [females 28 (44.4%), Crohn's 55 (87%)]. Outcomes of < 250, < 150, < 100 and < 50 mu gr/gr were achieved by 52 (82%), 51 (81%), 44 (70%) and 32 (50%), respectively. The median time for achieving these cutoffs was 4.8 (1.8-15.6), 7.9 (2.6-16.4), 10.0 (3.5-20.5) and 18.5 (7.0-64.7) months, respectively. Shorter time from diagnosis to treatment was associated with achievement of FC < 50 mu gr/gr (p = 0.03). There was no association between age, disease type, anti-TNF alpha type, inflammatory markers, disease activity indices at baseline and induction anti-TNF alpha trough concentration and FC response. Conclusions FC response was achieved by the majority of patients treated with anti-TNF alpha within a short period of time. FC normalization in responders required almost one year. Impact Fecal calprotectin response was achieved by the majority of pediatric patients within a relatively short period of time after anti-TNF alpha induction and maintenance therapy. Fecal calprotectin normalization required an average period of approximately one year in responders. The faster response of fecal calprotectin is associated with shorter time from diagnosis to anti-TNF alpha treatment. Inflammatory bowel disease treating physicians should be aware of the relatively prolonged time to fecal calprotectin normalization and to allow enough time for anti-TNF alpha therapy to express its full potential prior to significant interventions