In this prospective observational study, patients with confirmed ulcerative colitis, who are going to receive vedolizumab, ustekinumab, or tofacitinib will be enrolled after an informed consent. In the screening period, inclusion/exclusion criteria will be checked and if eligible and consented, demographic data, medical history, disease characteristics and disease activity data will be collected. Before drug administration (week 0), baseline lower GI endoscopy will be performed and colon tissues will be collected. Blood sample and fecal sample will also be collected. After induction therapy with each drug, clinical and endoscopic response will be evaluated at week 14 to week 16 and patients will be classified into responders non-responders. Combing clinical data, blood laboratory data, fecal inflammatory biomarker, genetic data, and colonic transcriptomic data, a prediction model for response to induction therapy will be developed and it will be validated in another patient group. Similarly, based on evaluation at week 52, a prediction model for maintenance response will also be developed and validated.
