Efficacy and Safety Study of Apremilast to Treat Active Ulcerative Colitis

Approximately 165 subjects (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), subjects who have a Mayo
endoscopy score ≤ 1 will have the opportunity to participate in the Extension Phase. Subjects
participating in the Extension Phase will receive apremilast for an additional 52 weeks
(Weeks 52 to 104). With the implementation of Amendment 4, subjects 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.

Inclusion Criteria:

Subjects must satisfy the following criteria to be enrolled in the study:

- Male or female aged 18 and over at the time of signing the informed consent.

- Must understand and voluntarily sign an informed consent form prior to any study
related assessments/procedures being conducted.

- Diagnosis of Ulcerative Colitis (UC) with a duration of at least 3 months prior to the
Screening Visit..

- Total Mayo Score (TMS) ≥ 6 to ≤ 11 (range: 0-12) at baseline, prior to randomization
in the study.

- Endoscopic subscore ≥ 2 (range: 0-3) on the Mayo score prior to randomization in the
study.

- Subjects must have had a therapeutic failure, been intolerant to, or have a
contraindication to, at least one of the following: oral aminosalicylates (ie,
5-aminosalicylic acid [5-ASA] compounds or sulfasalazine [SSZ]), budesonide, systemic
corticosteroids, or immunosuppressants (eg, 6-mercaptopurine [6-MP], azathioprine
[AZA], or methotrexate [MTX]).

Exclusion Criteria:

The presence of any of the following will exclude a subject from enrollment:

- Diagnosis of Crohn's disease, indeterminate colitis, ischemic colitis, microscopic
colitis, radiation colitis or diverticular disease-associated colitis.

- Ulcerative colitis restricted to the distal 15 cm or less (eg, ulcerative proctitis).

- Subjects who have had surgery as a treatment for UC or who, in the opinion of the
Investigator, are likely to require surgery for UC during the study.

- Clinical signs suggestive of fulminant colitis or toxic megacolon.

- Prior use of any TNF inhibitor (or any biologic agent).

- Prior use of mycophenolic acid, tacrolimus, sirolimus, cyclosporine or thalidomide.

- Use of IV corticosteroids within 2 weeks of the Screening Visit.

- Use of immunosuppressants (AZA, 6-MP or MTX) within 8 weeks of the Screening Visit.

- Use of topical treatment with 5-ASA or corticosteroid enemas or suppositories within 2
weeks of the Screening Visit.

- History of any clinically significant neurological, renal, hepatic, gastrointestinal,
pulmonary, metabolic, cardiovascular, psychiatric, endocrine, hematological disorder
or disease, or any other medical condition that, in the investigator's opinion, would
preclude participation in the study.