This Phase III, randomized, double-blind, multicenter, induction and maintenance study will evaluate the safety and efficacy of Afimkibart (RO7790121) in pediatric participants with moderate to severe active ulcerative colitis (UC).
Bodyweight >= 10 kilogram (kg)
Confirmed diagnosis of UC
Demonstrated intolerance or inadequate response (IR) to one or more of the following categories of drugs: systemic corticosteroids, immunomodulators, and/or biologic therapies as outlined in the protocol
Monogenic disorder pertaining to infant onset inflammatory bowel disease (IBD)
Current diagnosis of Crohn's disease (CD), abdominal/intrabdominal/perianal fistula and/or abscess, indeterminant colitis, IBD-unclassified, microscopic colitis, ischemic colitis, infectious colitis, radiation colitis, or active diverticular disease
Presence of an ostomy or ileoanal pouch
Current diagnosis or suspicion of primary sclerosing cholangitis