A Study to Evaluate Efficacy and Safety of MK-8690 in Participants With Moderately to Severely Active Ulcerative Colitis (MK-8690-002)

The main inclusion criteria include but are not limited to the following: * Has had ulcerative colitis (UC) (from onset of symptoms) for at least 3 months before Randomization * Has moderately to severely active UC * Has a weight ≥40 kg * Satisfies at least 1 of the criteria: Has had an inadequate response or loss of response to 1 or more protocol-specified treatments; protocol specified corticosteroid dependence; has been intolerant to 1 or more protocol-specified UC treatments * Is on treatment with any protocol-specified drugs during the study and meets drug stabilization requirements, as applicable The main exclusion criteria include but are not limited to the following: * Has a diagnosis of Crohn's Disease (CD) or indeterminate colitis (inflammatory bowel disease (IBD)-undefined) or other types of colitis or enteritis that may confound efficacy assessment * Has a current diagnosis of fulminant colitis and/or toxic megacolon * Has UC…