Study to Evaluate the Efficacy and Safety of Ponesimod (VSP-128) in Patients With Moderately to Severely Active Ulcerative Colitis

Inclusion Criteria: * Male and female subjects aged 18-75 years * Able to provide written informed consent * Diagnosis of ulcerative colitis for ≥90 days prior to screening * Three-component Mayo score of 5-9 with endoscopy subscore ≥2 and rectal bleeding subscore ≥1 * History of inadequate response, loss of response, or intolerance to at least one approved UC therapy Exclusion Criteria: * Severe or fulminant UC likely to require hospitalization or surgery * Diagnosis of Crohn's disease or other non-UC colitis * Prior exposure to S1P receptor modulators * Active or chronic infections * Clinically significant cardiovascular, hepatic, or other uncontrolled systemic disease * History of an allergic reaction or significant sensitivity to constituents of study drug