A Multicenter, Randomized, Double-Blind, Placebo Controlled Induction Study to Evaluate the Efficacy and Safety of Risankizumab in Participants With Moderately to Severely Active Ulcerative Colitis

Open to people ages 16-80

• Male or female aged >=18 to <= 80 years at the Baseline Visit. Where locally permissible, subjects 16 to < 18 years of age who meet the definition of Tanner stage 5 for development at the Baseline Visit.
• Confirmed diagnosis of ulcerative colitis (UC) for at least 3 months prior to Baseline.
• Active UC as assessed by Adapted Mayo Score and Endoscopic Subscore.
• Demonstrated intolerance or inadequate response to conventional therapy and tofacitinib (not a biologic) and one or more biologic therapies.
• Females must be postmenopausal for more than 1 year or surgically sterile or practicing specific forms of birth control.

• Participant with a current diagnosis of Crohn's disease (CD), inflammatory bowel disease-unclassified (IBD-U) or a history of radiation colitis or ischemic colitis.
• Participant receiving prohibited medications and treatment.
• Extent of inflammatory disease limited to the rectum as assessed by screening endoscopy.
• Participant with currently known complications of UC (e.g., megacolon).
• No known active Coronavirus Disease - 2019 (COVID-19) infection.