This is a randomized , double-blind, placebo-controlled study of approximately 70 patients with ulcerative colitis.

Inclusion Criteria:

• Able and willing to provide written informed consent
• 18-70 years of age
• Males and females with reproductive potential: Willing to use a reliable method of contraception
• Diagnosis of ulcerative colitis
• Eligible to receive biologic therapy
• Disease duration of >=12 weeks

Exclusion Criteria:

• Requirement for hospitalization due to severity of ulcerative colitis
• Moderate to severe anemia
• Any manifestation of ulcerative colitis or other conditions likely to require, in the investigator's judgment, treatment with >20 mg/day of prednisone, or prednisone equivalent, during the course of the study
• Pregnant or lactating
• Lack of peripheral venous access
• Inability to comply with study protocol
• History or presence of contraindicated diseases
• Congenital immune deficiency
• Active or prior infection with HIV or hepatitis B or C
• History of severe systemic bacterial, fungal, viral, or parasitic infections
• History of any other opportunistic infections within 12 weeks prior to initiation of study treatment
• Received a live attenuated vaccine within 4 weeks prior to screening
• Hospitalized within 4 weeks prior to screening
• Received any contraindicated therapy within 12 weeks prior to screening