A Study on the Safety of TAK-279 and Whether it Can Reduce Inflammation in the Bowel of Participants With Moderately to Severely Active Ulcerative Colitis

The main aim of this study is to learn if TAK-279 reduces bowel inflammation and symptoms compared to placebo. Another aim is to compare any medical problems that participants have when they take TAK-279 or placebo and how well the participants tolerate any problems. The participants will take capsules of either TAK-279 or placebo for up to 3 months (12 weeks). Then all the participants will receive TAK-279 for the rest of the treatment part of the study (1 year or 52 weeks). During the study, participants will visit their study clinic several times.