Exocrine Pancreatic Insufficiency's Prevalence in Active Crohn's Disease

Inclusion Criteria: * Age of 18 years or more * Crohn's disease diagnosed for more than 3 months. * Active Crohn's disease : CDAI score \> 150 + \[CRP \> 5 mg/L or faecal calprotectin \> 250mcg/g or endoscopic lesion or MRI lesion\] * Indication of a biological therapy (anti-TNFα, vedolizumab ou ustekinumab). Exclusion Criteria: * Crohn's disease that doesn't fit the previous criteria * Extended resection of small intestine (\>40cm) * Chronic pancreatitis diagnosed before inclusion * Contraindication to biological therapy (anti-TNFα, vedolizumab ou ustekinumab) * Pancreatic enzyme replacement therapy * Pregnant or breastfeeding woman * Patient under the protection of a conservator