Study of the Efficacy, Safety, Pharmacokinetics, Pharmacodynamics, and Immunogenicity of BCD-261 in Subjects With Moderate to Severe Active Ulcerative Colitis

Subjects meeting the eligibility criteria will be randomized in 5 groups to receive one of four studied dosage regimens of BCD-261 or placebo. The study groups will differ in drug dosages of BCD-261 (low, medium, high) during the induction and maintenance periods of therapy. After the primary endpoint assessment subjects in placebo group will be switched to BCD-261 medium studied dose.