Fast and sharp decrease in calprotectin predicts remission by infliximab in anti-TNF naïve patients with ulcerative colitis.

AIM: To evaluate the effect of infliximab induction therapy on calprotectin levels in patients with ulcerative colitis (UC). PATIENTS AND METHODS: In this prospective study 53 patients with active UC from 17 centers were treated with infliximab therapy (5mg/kg) at baseline, week 2, and week 6. Faecal calprotectin was measured every week. Sigmoidoscopies were performed at baseline, week 6 and week 10. RESULTS: Median calprotectin levels decreased from 1260 (IQR 278.5- 3418 ) at baseline to 72.5 (IQR 18.5 - 463) at week 10 (p<0.001). After 10weeks, infliximab therapy induced endoscopic remission and a decrease in calprotectin to<50mg/kg or at least a 80% decrease from baseline level in 58% of patients. A significant and steep decrease of calprotectin levels was seen at week 2 for patients with an endoscopic remission at week 10 as compared to patients who did not show a remission. (p<0.001). At week 10 an excellent correlation was found between endoscopic remission and clinical Mayo score reflected by an AUC of ROC analyses of 0.94 (0.87-1) and with calprotectin measurements (AUC 0.91 (0.81-1)) : all patients with calprotectin levels <50mg/kg, and a normal clinical Mayo score (=0) were in endoscopic remission. CONCLUSIONS: Infliximab induces a fast and significant decrease of faecal calprotectin levels in anti-TNF naive patients with ulcerative colitis predictive for remission of disease.