Randomized Placebo-Controlled Trial of Budesonide Multi-Matrix System (MMX®) 9 Milligrams (mg) in Participants With Ulcerative Colitis Currently on a 5-Aminosalicylic Acid (5-ASA)

Eligible participants will be randomized to 1 of the following 2 treatment arms: 1. Budesonide MMX 9 mg (1 tablet) 2. Placebo (tablet indistinguishable from budesonide MMX 9 mg tablet) The assigned study drug will be taken as a single oral tablet each morning after breakfast. In addition to the study drug, all participants will continue their existing background oral 5-ASA regimen during the treatment period.