Faecal calprotectin assay after induction with anti-Tumour Necrosis Factor α agents in inflammatory bowel disease: Prediction of clinical response and mucosal healing at one year.

BACKGROUND Faecal calprotectin levels correlate with inflammation in inflammatory bowel disease. We evaluated the role of faecal calprotectin after anti-Tumour Necrosis Factor α induction in inflammatory bowel disease patients to predict therapeutic effect at one year. METHODS Faecal calprotectin levels were measured in stools of 63 patients before and after induction of anti-Tumour Necrosis Factor α therapy. Clinical activity, measured by clinical indices, was assessed before and after biologic treatment. Clinical responders after induction were included in the study and colonoscopy was performed before and after one year of treatment to assess mucosal healing. RESULTS 63 patients (44 Crohn's disease, 19 ulcerative colitis) were prospectively included (41.2% males, mean age at diagnosis 33 years). A sustained clinical response during the first year was observed in 57% of patients; median faecal calprotectin was 106 μg/g after induction versus 308 μg/g pre-induction (p<0.0001). Post-induction faecal calprotectin was significantly lower in responders versus non-responders (p=0.0002). Post-induction faecal calprotectin had 83% sensitivity and 74% specificity (cut-off ≤ 168 μg/g) for predicting a sustained clinical response at one year (p=0.0001); also, sensitivity was 79% and specificity 57% (cut-off ≤ 121 μg/g) for predicting mucosal healing (p=0.0001). CONCLUSIONS In inflammatory bowel disease faecal calprotectin assay after anti-Tumour Necrosis Factor α induction can be used as a marker to predict sustained clinical response and mucosal healing at one year.