A Study of Mirikizumab (LY3074828) in Pediatric Participants With Moderately to Severely or Active Ulcerative Colitis

Inclusion Criteria: * Males or females weighing ≥10 kg and ≥2 and \<18 years old at the time of consent for screening. * Have moderate to severe UC. * Have failed corticosteroids, biologics, (for example, anti-tumor necrosis factor (TNF) antibodies or anti-integrin antibodies), immunomodulators (for example, azathioprine, thiopurines or methotrexate) or Janus Kinase (JAK)-Inhibitor treatment. * Have UC at least 3 months in duration before baseline, which includes endoscopic evidence of UC corroborated by a histopathology report. Exclusion Criteria: * Have Crohn's disease, Inflammatory Bowel Disease Unclassified, ulcerative proctitis or primary sclerosing cholangitis. * Have immune deficiency syndrome. * Previous bowel resection or intestinal surgery. * Evidence of toxic megacolon. * History or current evidence of cancer of the gastrointestinal tract.