Evaluation of Therapeutic Strategy to Prevent Crohn's Disease Endoscopic poSToperatIve recurreNce Based on earlY Dosage of Faecal Calprotectin

Crohn's disease (CD) (\> 200,000 patients in France) is a chronic inflammatory disease that can lead to progression of intestinal destruction and impaired quality of life. Despite the widespread use of biotherapies, intestinal resections remain frequent (50% of patients over time). Unfortunately, surgery is not curative since 75% of patients experienced post-endoscopic operative recurrence (POR) (i.e., recurrence of ulcerations) during the first year after surgery. Prevention of endoscopic POR (defined as a Rutgeerts index ≥ i2) is essential because endoscopic POR is highly predictive of clinical POR (i.e., recurrence of CD-related symptoms): \> 40% and \> 80% within 5 years for a Rutgeerts index ≥ i2 or ≥ i3, respectively. The recommended management is to start treatment after surgery to avoid endoscopic POR, and to perform a colonoscopy at 6 months (M6) with therapeutic escalation if endoscopic POR. Despite anti-TNF or ustekinumab treatment, the endoscopic POR rate remains high (30-40% at M6) leading to \> 40% clinical POR despite therapeutic escalation (90 mg/4 weeks with ustekinumab) potentially due to late therapeutic escalation. Innovative strategies are therefore needed to prevent endoscopic POR, such as the use of fecal calprotectin, a non-invasive biomarker associated with endoscopic CD activity. We have previously demonstrated that its variation between surgery and M3 allows for a value at M3 predictive of endoscopic POR at M6. In this study, we hypothesize, for the first time, that a strategy integrating fecal calprotectin measurement at M3 with earlier therapeutic escalation (M3 vs M6) in case of abnormal value or kinetics could decrease the rate of endoscopic POR at M6.