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 μg/g stool (range <5-24,000) declined to 372 μg/g (range 5-2430) by week 6, with a low level (<100 μg/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 µg/g, IQR: 197-819 and median 219 µg/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.