A Study to Investigate Efficacy and Safety of SAR441566 in Patients With Ulcerative Colitis

Eligibility Criteria

• * Male or female participants aged 18 to 75 years inclusive, at the time of signing the informed consent
• * Participants who have clinical evidence of active UC for ≥3 months before screening and confirmed by endoscopy during the screening period
• * Active moderate-to-severe UC at screening as defined by a modified Mayo Score (mMS) of 5 to 9 (without the Physician global Assessment (PGA), with a minimum rectal bleeding (RB) subscore ≥1, a minimum stool frequency (SF) subscore ≥1, a mMES ≥2 confirmed by central reader, a minimum sum of all subscores of 5, and a disease extent \>15 cm from the anal verge
• * Must have received prior treatment for UC (either "a" or "b" below or combination of both):
• 1. No prior exposure to Advanced Therapy (AT), but having inadequate response to, loss of response to or intolerance to standard treatment with any of the following compounds: 5-ASA, 6-MP, AZA, MTX, oral or intravenous (IV) corticosteroids or history of corticosteroid dependence (defined an inability to successfully taper corticosteroids without recurrence of UC) OR
• 2. Inadequate response to, loss of response to or intolerance to treatment with ≥1 approved AT such as a biologic agent (such as TNF antagonists, anti-integrin other than natalizumab, anti-IL-12/23, anti-IL-23, or experimental biologic UC therapeutics), or a small molecule (such as a JAKi or S1PRm) for UC
• * Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.
• * Participants with active CD, indeterminate colitis, ischemic colitis, microscopic colitis
• * Participants with the following ongoing known complications of UC: fulminant colitis, toxic megacolon, or any other manifestation that might require bowel surgery while enrolled in the study
• * Participant with prior colectomy, ostomy or ileoanal pouch, or anticipated colectomy during their participation in the study
• * Participants with fecal sample positive for ova or parasites, bacterial pathogens, or positive for Clostridium difficile B toxin in stools
• * Participants with active tuberculosis (TB) or a history of incompletely treated active TB or latent TB infection per local guidelines
• * Participants with Positive Hepatitis B surface antigen (HBsAg), or Hepatitis B core antibody (HBcAb) and/or Hepatitis C virus antibody (HCVAb) at the screening visit
• * Participants with any other active, chronic or recurrent infection, including recurrent or disseminated herpes zoster or disseminated herpes simplex
• * Participants with a known history of human immunodeficiency virus (HIV) infection or positive HIV-1 or HIV-2 serology at screening
• * Participants presenting with active malignancies, lymphoproliferative disease, or recurrence of either, within the 5 years before screening
• * If the participant has extensive colitis for ≥8 years or disease limited to left side of colon (ie, distal to splenic flexure) for \>10 years, regardless of age, a colonoscopy within 1 year of the screening visit is required to survey for dysplasia. Participants with dysplasia or cancer identified on biopsies will be excluded.
• * Female participants who is pregnant, breastfeeding, or is considering becoming pregnant during the study or within 3 months after the last dose of study drug
• * Infection(s) requiring treatment with IV anti-infectives within 30 days prior to the screening visit or oral/intramuscular anti-infectives within 14 days prior to the screening visit
• * Participants requiring or receiving any parental nutrition and/or exclusive enteral nutrition
• * Participants who received cyclosporine, tacrolimus, mycophenolate mofetil, or thalidomide within 30 days prior to screening
• * Participants who received fecal microbial transplantation within 30 days prior to screening
• * Participants who have ever been exposed to natalizumab (Tysabri®) or oral carotegrast methyl (Carogra®)
• * Participants who received IV corticosteroids within 14 days prior to screening or during screening period
• * Screening laboratory and other analyses show abnormal results.