Open-label V565 Target Engagement Study

Inclusion Criteria: * Established diagnosis of UC for 12 months or more * Distal disease, accessible by flexible sigmoidoscopy * Mild to moderate UC as defined as Mayo score between 3 - 10 with Mayo endoscopic sub score ≥1 Exclusion Criteria: * A known hypersensitivity to any of the inactive ingredients of the study treatment * A diagnosis of any IBD except UC * Isolated proctitis * Stool culture positive for C. difficile or other enteric infection * Untreated tuberculosis (TB); positive QuantiFERON-TB Gold Test result (performed by Central Laboratory) * Evidence of previous or present hepatitis B or C infection * Known severe viral infection within six weeks prior to Visit 1 * Current use of topical mesalazine or anti-infectives for serious infection (or within 1 week) * Anti-TNFα therapy other than the study drug * Parenteral or enteral nutrition therapy * Current use of any biologic agent * Primary failure or secondary loss of response (LOR) to use of a TNFα inhibitor * Contraindication to TNFα inhibitor * Clinically significant abnormal laboratory test result at screening * Taken an investigational drug within 3 months or 5 half-lives (whichever is longer) prior to the first dose in this study.