Fecal biOmarker Response Evaluation for Super-Early Efficacy in Ulcerative Colitis

Dynamic Changes of Fecal Calprotectin and Fecal Immunochemical Test for Early Prediction of Biologic Treatment Efficacy in Ulcerative Colitis: A Multicenter, Prospective Cohort Study

This multicenter prospective cohort aims to evaluate whether combined changes in fecal calprotectin (FC) and fecal immunochemical test (FIT) at **Week 2 and Week 4** after initiating biologic therapy (vedolizumab or infliximab) can predict clinical response at **Week 14** and mucosal healing at **Week 52** in moderate-to-severe ulcerative colitis (UC) patients. Primary outcome: clinical remission rate at Week 14.

Inclusion Criteria:**

• Age 18-75 years, UC diagnosis with endoscopic Mayo score (MES) ≥2
• Moderate-to-severe activity (Full Mayo Score ≥6)
• Initiating vedolizumab or infliximab within 7 days after baseline
• Biologic-naïve or prior exposure to only one TNF-α inhibitor

**Exclusion Criteria:**

• Pregnancy/lactation
• Contraindications to biologics (e.g., active TB, severe infection)
• Experimental drug use within 4 weeks prior to baseline