The Purpose of This Study is to Evaluate the Efficacy and Safety of 627 in the Treatment of UC

Inclusion criteria

• Able to understand and comply with the requirements of the study protocol, and sign the written informed consent form (ICF).
• Male or female subjects aged 18-75 years old when signing the ICF.
• Subjects must have been diagnosed with UC for at least 3 months prior to randomization.
• Moderate to Severe Active Ulcerative Colitis (UC).
• Inadequate or lost response, intolerance to one or more therapies, or corticosteroid dependence.
• Female subjects of childbearing potential and male subjects (and their female partners) must use highly effective contraception from the screening period through at least 6 months after the last dose. The subjects must have no plans for pregnancy, sperm donation, or oocyte donation during the same period (from screening through at least 6 months post-last dose).

Exclusion criteria

• History of severe opportunistic infection within 2 months prior to screening or randomization that remains not adequately controlled.
• Receiving protocol-prohibited treatments prior to screening or randomization.
• Presence of any laboratory test abnormalities during screening and/or determination by the investigator that enrollment in the study may pose uncontrollable safety risks to the subject.
• Positive hepatitis B test result, positive hepatitis C virus antibody (HCV Ab), positive human immunodeficiency virus antibody (HIV Ab), or positive serum Treponema pallidum antibody (TP Ab) during screening, as specified in the protocol.
• History of clinically significant cardiovascular and cerebrovascular diseases within 6 months prior to screening.
• History of any malignancy within 5 years prior to screening or currently active malignancy.
• Allergy to the investigational medicinal product, any of its components, or excipients.
• History of alcohol or substance abuse within 6 months prior to screening.
• Undergone major surgery within 6 months prior to screening or planned major surgery during the study period.
• Blood donation or significant blood loss within 4 weeks prior to screening.
• Participation in any drug clinical trial within 3 months prior to screening or within 5 half-lives of the investigational drug (whichever is longer).
• Vaccination with live/attenuated live vaccines within 4 weeks prior to screening or planned vaccination during the study period.
• Pregnant or lactating female subjects.
• Other conditions deemed unsuitable for trial participation by the investigator.