A study on the safety & effectiveness of RO7790121 in the treatment of moderately to severely active UC

Ulcerative colitis (UC) is a condition in which the lining of the large intestine (colon) and rectum become inflamed. It is a form of inflammatory bowel disease (IBD) and occurs in both children and adults. For patients with moderately to severely active UC there is an  unmet medical need for treatments with better benefit-risk profiles that lessen inflammation, prevent relapses and subsequently improve the long-term prognosis of patients with UC.

The purpose of this study is to compare the effects, good or bad, of RO7790121 versus placebo in patients with ulcerative colitis. In this study, participants will get either RO7790121 or placebo (a placebo looks like a drug but has no active ingredient). Once a participant completes the study, or if the study doctor determines that the patient's condition has not improved or has worsened during the study, the patient will have the opportunity to participate in an open-label extension phase of the study. The open-label extension phase will also assess the long-term effects (good or bad) of RO7790121, and, if there is a good effect, how long this effect may last.