To Evaluate the Efficacy and Safety of FE 999315 in Japanese Subjects With Mild to Moderate Active Ulcerative Colitis

Inclusion Criteria: * Male and female patients, 16 to 75 years old, diagnosed with ulcerative colitis. * Diagnosis of ulcerative colitis in active phase of mild to moderate entity. * Female patients must fulfill at least one of the following criteria: Post-menopausal (women ≥45 years with no menstrual period for at least 12 months without an alternative medical cause), surgically sterile, using a medically approved contraception throughout the trial period or her male partner using medically approved contraception throughout the trial period. * Male patients must agree to use medically approved contraception throughout the trial period. Exclusion Criteria: * Patients with limited distal proctitis. * Patients with infectious colitis. * Patients with history of colectomy. * Patients with severe diseases in other organs and systems. * Evidence or history of toxic megacolon. * Women who wish to become pregnant during the trial period