This study is for adults with Ulcerative Colitis (UC), a condition causing inflammation in the colon. The study aims to test the effectiveness of two drugs, Vedolizumab and Tofacitinib, first together for 8 weeks, and then Vedolizumab alone for another 44 weeks if the initial treatment works. Vedolizumab and Tofacitinib are medicines targeting the immune system to reduce inflammation. Participants are checked for their response after 8 weeks and continue if they respond well. The study will last up to 76 weeks, with follow-up for safety.

• The study will take place in the United States and Canada.
• Participants will be checked for progress and safety throughout the study.
• Involves 8 weeks of combination therapy and potentially 44 weeks of single therapy.

Eligible participants should have moderate to severe UC and should have tried no more than two previous treatments that didn't work well. People with certain complications or infections, or who have used specific drugs recently, may not join. It's important to check with your doctor if you meet the criteria or have questions about joining the study.