The long-term outcome of anti-tumor necrosis factor-α therapy related to fecal calprotectin values during induction therapy in pediatric inflammatory bowel disease

Objective. Monitoring fecal calprotectin (FC) could assist in the assessment of the therapeutic response of inflammatory bowel disease (IBD). There are few studies on long-term prognosis related to the FC value response to infliximab induction therapy, thus providing the aim of this study on pediatric patients. Methods. FC levels were measured during the induction and maintenance phase of infliximab therapy (5 mg/kg) in 76 pediatric IBD patients introduced to maintenance therapy. The long-term outcomes and clinical disease activity were retrospectively related to the FC response to induction. Results. The median pretreatment FC level of 817 mu g/g stool (range <5-24,000) declined to 372 mu g/g (range 5-2430) by week 6, with a low level (<100 mu g/g) in 35% (pooled comparable data for ulcerative colitis and Crohn's). Clinical activity indices showed remission in 59% (pediatric Crohn's disease activity index: <10, n = 33; pediatric ulcerative colitis activity index: <10 n = 12). In 49 patients (64%), infliximab therapy was discontinued (inadequate effect/surgery = 27; remission/bridging to azathioprine = 12; adverse effect = 6; antibodies to infliximab n = 4) during the study period with a median follow up of 1.1 years (interquartile range [IQR]: 0.71-4.4). Those who discontinued the therapy within the first year due to an inadequate effect had higher median FC level during induction than the other patients (median 633 mu g/g, IQR: 197-819 and median 219 mu g/g, IQR: 71-508, respectively; p < 0.025) and were less frequently in clinical remission at week 6 (p < 0.01). Conclusions. The long-term prognosis of infliximab therapy is related to the response to induction therapy in pediatric IBD and reflected in low FC values between weeks 2 and 6 and clinical remission.