An Induction Study of Mirikizumab in Participants With Moderately to Severely Active Ulcerative Colitis (LUCENT 1)

Inclusion Criteria: * Diagnosis of UC for at least 3 months prior to baseline. * Confirmed diagnosis of moderately or severely active UC, as assessed by the modified Mayo score (MMS). * Demonstrated an inadequate response to, a loss of response to, or an intolerance to conventional or to biologic therapy for UC. * If female, must meet the contraception requirements. Exclusion Criteria: * Participants with a current diagnosis of Crohn's disease or inflammatory bowel disease-unclassified (indeterminate colitis). * Participants with a previous colectomy. * Participants with current evidence of toxic megacolon. * Prior exposure to anti-IL12p40 antibodies (e.g. ustekinumab) or anti-IL-23p19 antibodies (e.g. risankizumab, brazikumab, guselkumab or tildrakizumab).