Acute Severe Ulcerative Colitis

The goal of this clinical trial is to learn comparative effectiveness and safety of Upadacitinib vs Corticosteroids as First-Line Therapy for Acute Severe Ulcerative Colitis. The main questions it aims to answer are: 1. Whether upadacitinib can effectively induce remission in acute severe ulcerative colitis with an efficacy non-inferior to that of corticosteroids. 2. What adverse reactions may occur with upadacitinib in the treatment of acute severe ulcerative colitis? Researchers will compare upadacitinib with corticosteroids to evaluate the efficacy of upadacitinib in the treatment of acute severe ulcerative colitis.Participants will: 1. Upadacitinib group: Upadacitinib extended-release tablets 45 mg once daily for 8 weeks, then adjusted to 30 mg once daily. 2. Corticosteroid group: Methylprednisolone for injection 60 mg/day. If clinical response is achieved, switch to oral prednisone acetate tablets after 5 days (calculated at 0.75 mg/kg/day), followed by a weekly prednisone taper of 5 mg. When the dose is reduced to 20 mg, taper by 2.5 mg weekly until discontinued, with mesalazine 4 g/day as maintenance therapy. 3. Take drug Upadacitinib or Corticosteroid every day for 3 months 4. Visit the clinic once every 2 weeks for checkups and tests 5. Record the patient's bowel movements and the presence of symptoms such as abdominal pain, while performing colonoscopy, ultrasound examination, and blood tests at the specified time points.

This clinical trial aims to evaluate the comparative efficacy and safety of upadacitinib versus infliximab as second-line treatments for acute severe ulcerative colitis, addressing the following key questions: (1) Can upadacitinib as a second-line therapy effectively induce remission in acute severe ulcerative colitis with efficacy non-inferior to infliximab? (2) What adverse reactions may occur with upadacitinib in the treatment of acute severe ulcerative colitis? Researchers will also compare the efficacy of upadacitinib with that of corticosteroids to assess its therapeutic effect. Participants will be assigned to either the upadacitinib group (receiving upadacitinib extended-release tablets 45 mg once daily for 8 weeks, followed by 30 mg once daily) or the infliximab group (receiving an initial dose of 5 mg/kg, with additional doses at week 2, week 6, and every 8 weeks thereafter at the same dose). The treatment duration is 3 months, with outpatient visits for examinations and tests every two weeks. Patients will record their bowel movements and symptoms such as abdominal pain, and undergo colonoscopy, ultrasound examinations, and blood tests at specified time points.

In adults hospitalized with acute severe ulcerative colitis who fail to respond to intravenous steroids, does treatment with a combination of infliximab and tofacitinib, compared with infliximab alone or tofacitinib alone, result in higher rates of early clinical remission and mucosal healing, and fewer treatment-related complications over a 10 week period

Ulcerative colitis (UC) is a chronic disease characterized by acute episodes of bloody diarrhea with varying degrees of severity. The most feared event, acute severe UC, can lead to life-threatening and systemic complications. Little is known about the determinants of severity in UC. The investigators hypothesize that distinct severity phenotypes of UC arise from intricated host-microbiota mechanisms influencing repair mechanisms. Our first and main objective is to study the natural history of UC during a one-year time period in a cohort of patients.