Safety and Efficacy Trial of RPC1063 for Moderate to Severe Ulcerative Colitis

Inclusion Criteria: * Aged 18 to 75 years (at screening for Cohort 1 and 2) * UC confirmed on endoscopy * Moderately to severely active UC (May score 6-12) * Currently receiving treatment with aminosalisylate, prednisone, or budesonide * Can be receiving azathioprine, mercaptopurine, or methotrexate, but treatment will be stopped prior to randomization Exclusion Criteria: * Have severe extensive colitis as evidence by: * Physician judgment that the patient is likely to require colectomy or ileostomy within 12 weeks of baseline. * Current or recent (within 3 months) evidence of fulminant colitis, toxic megacolon, or bowel perforation. * Diagnosis of CD, indeterminate colitis, or the presence of fistula consistent with CD or microscopic colitis, radiation colitis, or ischemic colitis * Clinically relevant cardiovascular conditions or other relevant diseases that could impact the implementation or interpretation of the trial, or put the patient at risk * History of uveitis or unknown macular edema * Pregnancy, lactation, or a positive serum β-human chorionic gonadotropin (β-hCG) measured during screening