Patients diagnosed with moderate to severe CD or UC by the end of the study period were selected. After obtaining informed consent, treatment with infliximab-based drugs was initiated. Basic patient information and medical history were collected. The treatment process was followed, and the drug treatment plan was adjusted based on physician experience. Follow-up and disease assessments were conducted at 0, 4, 8, 16, 24, 48, and 54 weeks. At corresponding follow-up time points, blood, stool, and tissue samples were collected for gastrointestinal endoscopy, imaging examinations, laboratory tests, symptom self-assessment by participants, adverse reaction assessment, and nutritional risk screening. The efficacy and safety of IL-23 inhibitor treatment for CD or UC were comprehensively evaluated.

After the study began, regular check-ups and evaluations were required when necessary or before medication administration. Venous blood samples were collected, or fecal collection boxes were provided for stool collection. When intestinal endoscopy was required for re-examination, one piece of normal and one piece of diseased intestinal mucosa tissue were collected each time. When surgery was required, two pieces of normal and two pieces of diseased intestinal mucosa tissue were collected each time. Sample collection does not affect the disease treatment and evaluation process. If any discomfort occurs during IL-23 inhibitor treatment, or if there are new changes in the condition or any unexpected situations, including hospitalization at other medical institutions, disability, etc., regardless of whether they are related to the study, participants should notify the investigator promptly to allow for judgment and appropriate medical treatment or advice to ensure safety.

Inclusion Criteria:

1. Male or female subjects aged between 18 and 65 years at the baseline visit;
2. Patients diagnosed with CD and UC as per the Chinese Guidelines for the Diagnosis and Treatment of Crohn's Disease (2023 · Guangzhou) and the Chinese Guidelines for the Diagnosis and Treatment of Ulcerative Colitis (2023 · Xi'an);
3. If the subject is a fertile female, a pregnancy test must be conducted at the baseline to rule out pregnancy. The entire trial process must follow the contraceptive recommendations of this project (see below); women without reproductive potential (defined as post-menopause or permanent surgical sterilization) do not need to undergo a pregnancy test at the baseline;
4. The subjects fully understand the purpose of the trial, and should have a basic understanding of the pharmacological effects of the trial drugs and the possible adverse reactions; in accordance with the spirit of the Helsinki Declaration, they voluntarily sign the informed consent form and comply with the requirements of this research protocol.

Exclusion Criteria:

1. Diagnosed with ischemic enteritis, infectious enteritis, radiation enteritis, NSAIDs-related enteritis, and other autoimmune enteropathies;
2. Unable to administer IL-23 inhibitors regularly by intravenous or subcutaneous injection;
3. Evidence of toxic megacolon was detected during screening;
4. Previously underwent small bowel resection, ileocecal resection, extensive colon resection, subtotal resection or total colon resection, rectal resection, ileostomy, colostomy;
5. Subjects who need surgery due to the condition or plan to undergo elective surgery during the study;
6. Complicated with severe liver and kidney dysfunction;
7. Complicated with active bacterial or viral infections, chronic infections;
8. Biologic agents are contraindicated such as active tuberculosis with positive chest X-ray or strongly positive tuberculin skin test, active tuberculosis within the past five years, myocardial infarction, heart failure or demyelinating neurological diseases;
9. Had severe opportunistic infections during screening, such as severe or recurrent herpes zoster, active cytomegalovirus infection, Pneumocystis jirovecii, Histoplasma capsulatum, etc. infections;
10. Have a history of gastrointestinal dysplasia, or any biopsy during endoscopic examination has revealed dysplasia, excluding completely resected low-grade dysplastic lesions; Patients with a known history of lymphoid tissue proliferative diseases (including lymphoma), or with signs and symptoms of lymphoid tissue proliferative diseases (such as lymphadenopathy and/or splenomegaly); Patients with current or past malignant tumors.