This is a multicenter, double-blind, randomized study to compare the safety, effectiveness and immunogenicity (level and body resistance to drugs) of two biological drugs administered intravenously - vedolizumab (a drug not registered in pediatric patients) and infliximab (used as standard therapy) in pediatric patients with ulcerative colitis aged 6-17 years.
Assessment of the safety and effectiveness of vedolizumab induction therapy compared to standard infliximab therapy in pediatric patients with ulcerative colitis "VEDI-UC”