A Study to Evaluate the Safety, Pharmacokinetics, and Preliminary Efficacy of ENC1018 Capsules in Patients With Moderate-to-severe Active Ulcerative Colitis (UC)

Inclusion Criteria:

1. Aged between 18 and 75 years, male or female.

2. Ulcerative colitis has been diagnosed at least 3 months before screening, and thediagnosis must be confirmed by endoscopy or radiology and histology.

3. Have moderate to severe active ulcerative colitis, defined as a modified Mayo score ≥6.

4. Poor response or intolerance to at least one conventional therapy (aminosalicylicacids, corticosteroids, or immunomodulators) or biologics (anti-TNF, anti-α4β7integrin, or anti-IL-12/23 antibody drugs) as determined by the investigator.

5. If subjects are taking oral aminosalicylic acids or oral glucocorticoids, theirdoses must remain stable for at least 2 weeks prior to enrollment and for theduration of the study.

6. Voluntarily sign the informed consent and be willing to follow the researchprocedures and complete the test in accordance with the protocol.

Exclusion Criteria:

1. Diagnosed with undefined colitis, infectious colitis, ischemic colitis, fulminantcolitis, toxic megacolon, or other chronic intestinal diseases other than UC such asCrohn's disease (CD), intestinal tuberculosis, radiation enteritis, and intestinalbelcet's disease.

2. Never received any previous treatment for UC.

3. Participated in any other clinical trial within 3 months prior to screening (exceptthose who have only participated in clinical trial screening without using theexperimental drug).

4. Subjects with a history of alcohol or drug abuse and complete abstinence for lessthan 6 months before enrollment.

5. Received any live vaccine within 6 weeks prior to enrollment or planned to receiveany live vaccine during the study period or within 6 weeks after the last use of theinvestigational drug.

6. Experienced major trauma or major surgery within 4 weeks before enrollment;

7. Have any other gastrointestinal diseases that may affect the absorption of oraldrugs or have undergone gastrectomy or gastric bypass surgery.

8. Assessed by investigator as needing or receiving total parenteral nutrition and/ortotal enteral nutrition.

9. Allergy to the test drug or its ingredients.

10. Surgical treatment for ulcerative colitis, including but not limited to ostomy,ileal pocket anal anastomosis, and intestinal resection, is required during prior oranticipated study.

11. Pregnant and lactating women; Or women of childbearing age who have positive bloodpregnancy test results during screening; Or had a birth plan throughout the trialperiod and within 3 months after the end of the study; Or unwilling to use one ormore types of physical contraception during the trial and for three months after theend of the study.

12. The investigator believes that participation in this study is not appropriate forother reasons; Or other conditions that may confuse or interfere with the safety,tolerability, or pharmacokinetic evaluation of the investigational drug.