Observing How IL-23 Inhibitors Work in Adults With Active Crohn's Disease

Who can take part

• Age 18 to 75 years
• Diagnosis of Crohn's disease based on clinical presentation, endoscopy, imaging, and/or histopathology, consistent with ECCO criteria or Chinese IBD consensus criteria
• Active Crohn's disease with a baseline Crohn's Disease Activity Index (CDAI) score of 150 to 450, and at least one of the following objective inflammatory findings: (1) Endoscopic activity within 1 month before enrollment, defined as Simple Endoscopic Score for Crohn's Disease (SES-CD) >=6 for ileocolonic or colonic disease, or SES-CD >=4 for isolated ileal disease, (2) Active intestinal inflammation on bowel ultrasound, computed tomography enterography (CTE), or magnetic resonance enterography (MRE), (3) Serum C-reactive protein (CRP) above the upper limit of normal, (4) Fecal calprotectin (FC) >=250 ug/g
• Planned initiation of IL-23 inhibitor therapy in routine clinical practice, including guselkumab or risankizumab, with no prior exposure to IL-23 inhibitors
• Prior treatment history for the IL-23 inhibitor cohort may include biologic-naive or biologic-experienced patients; prior exposure to TNF inhibitors, vedolizumab, or ustekinumab is permitted
• If receiving concomitant medications, doses should be stable for at least 2 to 4 weeks before enrollment, including oral corticosteroids, azathioprine, 6-mercaptopurine, methotrexate, or 5-aminosalicylic acid
• Able to understand the study procedures, provide written informed consent, and comply with follow-up and biospecimen collection requirements
• Additional criteria for the concurrent prospective TNF inhibitor cohort used in the nested comparative analysis: (1) Participants must be bio-naive, defined as no prior exposure to any biologic agent (including TNF inhibitors, vedolizumab, ustekinumab, etc.) or targeted small-molecule therapy (such as JAK inhibitors), (2) Participants must also meet Inclusion Criteria 1, 2, 3, 6, and 7 above, (3) Participants must be planned to initiate TNF inhibitor therapy in routine clinical practice

Who cannot take part

• Prior exposure to any IL-23 inhibitor, including guselkumab, risankizumab, mirikizumab, or other IL-23-targeted agents
• Diagnosis of inflammatory bowel disease other than Crohn's disease, or other intestinal disorders that may confound diagnosis, including ulcerative colitis, IBD-unclassified, intestinal tuberculosis, ischemic colitis, or radiation enteritis
• Crohn's disease requiring urgent surgery or associated with severe complications, including active bowel perforation, uncontrolled fistula with severe infection, or complete bowel obstruction
• Active infection or high-risk infectious condition, including active tuberculosis, latent tuberculosis without appropriate prophylaxis, active hepatitis B or C, HIV infection, or severe/recurrent infection history
• Current or prior malignancy, except adequately treated non-melanoma skin cancer or cervical carcinoma in situ with no evidence of recurrence
• Severe systemic disease or other condition that, in the investigator's judgment, makes participation unsuitable, including severe cardiac, hepatic, or renal dysfunction, uncontrolled autoimmune disease, or psychiatric disease affecting adherence
• Pregnancy, breastfeeding, or planned pregnancy during the study period
• Inability to complete follow-up, poor compliance, or recent participation in another interventional clinical trial