A Phase 2 Safety and Efficacy Study of Tulisokibart (MK-7240/PRA023) in Subjects With Moderately to Severely Active Ulcerative Colitis (MK-7240-005)

The purpose of this study is to assess the safety and efficacy of tulisokibart in participants with moderately to severely active Ulcerative Colitis (UC). After the completion of the 12-week induction, all participants have the option to continue in the open-label extension for up to 170 weeks.

Inclusion Criteria: The main inclusion criteria include but are not limited to the following: * Confirmed diagnosis of ulcerative colitis (UC) * Has moderately to severely active UC as defined by 3-component Modified Mayo score * Must have corticosteroid dependence or have had no response, insufficient response, loss of response, and/or intolerance to at least one of the following therapies: corticosteroid, immunosuppressants, or an approved anti-tumor necrosis factor (anti-TNF), anti-integrin, anti-interleukin 12/23 (anti-IL12/23), Janus kinase (JAK) inhibitor, Sphingosine 1-phosphate receptor (S1PR) modulator. Exclusion Criteria: The main exclusion criteria include but are not limited to the following: * Has diagnosis of Crohn's disease or indeterminate colitis * Has current evidence of fulminant colitis, toxic megacolon, bowel perforation, total proctocoloectomy or partial colectomy * Has current or impending need for colostomy or ileostomy * Has had surgical bowel resection within 3 months before screening * Has past or current evidence of definite low-grade or high-grade colonic dysplasia not completely removed