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

Inclusion Criteria:

• Male or female aged >=18 to <= 80 years at the Baseline Visit. Where locallypermissible, subjects 16 to < 18 years of age who meet the definition of Tannerstage 5 for development at the Baseline Visit.

• Confirmed diagnosis of ulcerative colitis (UC) for at least 3 months prior toBaseline.

• Active UC as assessed by Adapted Mayo Score and Endoscopic Subscore.

• Demonstrated intolerance or inadequate response to conventional therapy andtofacitinib (not a biologic) and one or more biologic therapies.

• Females must be postmenopausal for more than 1 year or surgically sterile orpracticing specific forms of birth control.

Exclusion Criteria:

• Participant with a current diagnosis of Crohn's disease (CD), inflammatory boweldisease-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 screeningendoscopy.

• Participant with currently known complications of UC (e.g., megacolon).

• No known active Coronavirus Disease - 2019 (COVID-19) infection.