Efficacy and Safety Study of Apremilast to Treat Active Ulcerative Colitis

The purpose of the study is to evaluate the clinical efficacy, safety and tolerability of apremilast (30 mg twice daily \[BID\] and 40 mg BID), compared with placebo, in participants with active Ulcerative Colitis (UC).

Approximately 165 participants (55 subjects per arm) will be randomized in a 1:1:1 ratio to receive oral apremilast (30 mg BID or 40 mg BID), or identically appearing placebo BID for up to 12 weeks, followed by 40 weeks of blinded treatment with apremilast (30 mg BID or 40 mg BID). At the end of the Blinded Active-treatment Phase (Week 52), participants who have a Mayo endoscopy score ≤ 1 will have the opportunity to participate in the Extension Phase. Participants enrolled in the Extension Phase will receive apremilast for an additional 52 weeks (Weeks 52 to 104). With the implementation of Amendment 4, participants entering the Extension Phase will receive apremilast 30 mg BID. Subjects currently in the Extension Phase who are receiving apremilast 40 mg BID will be switched to 30 mg BID at the next scheduled visit.