A Maintenance Study to Investigate the Efficacy and Safety of Duvakitug in Participants With Moderately to Severely Active Ulcerative Colitis

This is a multicenter, randomized, double-blind, placebo-controlled Phase 3 maintenance study to evaluate the efficacy and safety of duvakitug in participants with moderately to severely active Ulcerative Colitis (UC). Study details include: The study duration may be up to 286 weeks including: * 40-week Pivotal Maintenance Sub-Study * 240-week Open-Label Extension (OLE) Sub-Study * 45-day Follow-up Visit Note: For the participants who do not enroll into OLE Sub-Study, the duration will be up to 46 weeks, including the 40-week maintenance period and a 45-day follow-up visit. The treatment duration may be up to 280 weeks including: * 40 weeks in Pivotal Maintenance Sub-Study * 240 weeks in OLE Sub-Study The total number of on-site visit will be up to 32: * 21 visits in the Pivotal Maintenance Sub-Study. * 11 visits in the OLE Sub-Study.