Inclusion Criteria:

• Diagnosis of ulcerative colitis (UC) established at least 12 weeks before screening including both endoscopic evidence and a histopathology report consistent with a diagnosis of UC

• Moderately to severely active UC, defined as a baseline (Week I-0) modified Mayo score of 5 to 9, inclusive, using the endoscopy subscore obtained during the central review of the screening video endoscopy

• An endoscopy subscore greater than or equal to (>=) 2 as obtained during central review of the screening video endoscopy

• For adolescent participants >=12 to less than (<) 18 years of age, body weight must be >=40 kilograms (kg) at baseline (Week I-0)

• Adult female participants of childbearing potential and all adolescent female participants must have a negative highly sensitive serum pregnancy test (beta-human chorionic gonadotropin [β-hCG]) at screening and a negative urine pregnancy test at Week I-0 prior to administration of study intervention and agree to further pregnancy tests

• Demonstrated an inadequate response, loss of response, or failure to tolerate previous conventional therapy (advanced drug therapy [ADT]-naïve) or advanced therapy defined as biologics and/or advanced oral agents for the treatment of UC (ADT-inadequate responder [IR]) as defined in the protocol

Exclusion Criteria:

• Participants with current known complications of UC such as fulminant colitis, toxic megacolon, or any other manifestation that might require colonic surgery while enrolled in the study

• Presence of a stoma

• Presence or history of a fistula

• Colonic resection within 24 weeks before baseline or any other intra-abdominal or other major surgery performed within 12 weeks before baseline

• History of extensive colonic resection (that is, less than [<] 30 centimeter [cm] of colon remaining) or colonic resection that could impair the use of disease severity assessments (for example Mayo Score) to assess response to study intervention

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 01/07/2026. Questions regarding updates should be directed to the study team contact.