Inclusion Criteria:

• Females must be of non-childbearing potential evidenced by being surgically sterile, postmenopausal for at least 12 months or be using acceptable contraception methods such as contraceptive pill, or two forms of barrier contraception.
• Disease Activity Index (DAI) Score of 6-10 (inclusive) at the Baseline Visit.
• Previous colonoscopic and biopsy diagnosis of ulcerative colitis with negative evaluation of the ileum within 3 years of the screening visit.
• Endoscopic evidence of moderate or severe mucosal disease as assessed by flexible sigmoidoscopy, with a minimum confirmed diagnosis of moderate ulcerative colitis.

• The following concomitant prescription medications for ulcerative colitis are permitted if the following conditions are met:

  1. Oral 5-aminosalicylic acid (5-ASA )therapy if the following 2 criteria are met:

     1. Must be on a stable dose 2 weeks prior to baseline
     2. Must maintain the stable dose until treatment end.

  2. Azathioprine or 6-mercaptopurine or methotrexate if the 4 following criteria are met:

     1. On therapy continually for at least 3 months prior to baseline.
     2. And on a stable dose for at least 2 weeks prior to baseline.
     3. And must maintain the stable dose until the end of study drug treatment.

Exclusion Criteria:

• History of colonic or rectal surgery, excluding hemorrhoidal surgery or an appendectomy.
• Pregnant or breast-feeding females.
• Diagnosis of diabetes, heart failure, unstable angina, hepatic cirrhosis, kidney failure, adrenocortical insufficiency, or any other unstable medical condition.
• Known hypersensitivity to corticosteroids
• Use of oral 5-aminosalicylic acid (5-ASA) or oral corticosteroids during the immediate screening period.
• Use of immunosuppressive drugs or antibiotics at any time within four weeks prior to screening.
• Diagnosis of Crohn's disease; indeterminate colitis; microscopic colitis; ischemic, infectious (e.g., salmonella, shigella, etc.), or amebic colitis; or gonococcal proctitis; Clostridium difficile colitis.
• History of tuberculosis or HIV
• Clinically significant abnormal laboratory test results, unless regarded by the Investigator as related to ulcerative colitis
• History of alcohol or drug abuse
• Known malignancy or history of malignancy that would reduce life expectancy
• Recent immunization with live viral vaccines
• History of or active peptic ulcer disease or gastritis
• Generalized infections such as systemic fungal or hepatitis B or C
• History of steroid induced severe hypertension, steroid-induced psychosis, or any other severe steroid-related adverse reaction