- Receiving 5-ASA treatment for at least two months and a stable dose of oral 5 ASA for at least two weeks prior to randomization. Concurrent treatment with prednisone, or equivalent glucocorticoid ≤ 20 mg/day is acceptable as follows: minimum dosing of 4 weeks prior to screening AND stable dose for 2 weeks prior to screening AND expected to remain on a constant dose during the trial. Use of 5-ASA compounds is not required for those subjects who have failed treatment with 5-ASA compounds, or are allergic or intolerant.