This clinical trial is focused on studying the effects of a medication called Vedolizumab in children and teenagers with a condition known as Ulcerative Colitis. Ulcerative Colitis is a disease that causes inflammation and sores in the lining of the large intestine, which can lead to symptoms like abdominal pain and diarrhea. The study aims to evaluate how effective and safe Vedolizumab is when used as a long-term treatment for those who have shown improvement after initial treatment with the same medication.

Participants in the study will receive Vedolizumab through an intravenous infusion, which means the medication is given directly into a vein. The study will compare two different dosing schedules of Vedolizumab to see which is more effective in maintaining remission, which means keeping the disease under control without symptoms. The study will last for about 54 weeks, during which the participants’ health and response to the treatment will be closely monitored. Some participants may receive a placebo, which is a substance with no active medication, to help researchers understand the true effects of Vedolizumab.

Throughout the study, the participants’ progress will be assessed using a scoring system that measures various symptoms of Ulcerative Colitis, such as stool frequency and rectal bleeding. The goal is to determine if Vedolizumab can help achieve and maintain remission in young patients with moderate to severe Ulcerative Colitis. The study will also look at the safety of the medication by monitoring any side effects or adverse reactions that may occur during the treatment period.