Phase 3b safety and efficacy study of Apremilast to treat moderate to severe plaque-plaque psoriasis

- Males or females, ≥ 18 years of age - Diagnosis of chronic, moderate to severe plaque psoriasis for at least 12 months prior to Screening, and a candidate for phototherapy and/or systemic (including etanercept) therapy - Had an inadequate response, intolerance, or contraindication to at least 1 conventional systemic agent for the treatment of psoriasis. - No prior exposure to biologics for treatment of psoriatic arthritis or psoriasis

- Other than psoriasis, history of any clinically significant and uncontrolled systemic diseases; any condition, including the presence of laboratory abnormalities, which would place the subject at unacceptable risk if he/she were to participate in the study. - Pregnant or breast feeding. - Have failed more than 3 systemic agents for treatment of psoriasis. - History of allergy to any component of the investigational product (IP), including human immunoglobulin (Ig) proteins or allergy to etanercept. - Hepatitis B surface antigen or anti-hepatitis C antibody positive at Screening. - Latent, active tuberculosis (TB) or inadequately treated TB; nontuberculous mycobacterial infection or opportunistic infection (eg, cytomegalovirus, Pneumocystis carinii, aspergillosis, Clostridium difficile). - Have a history of, or ongoing, chronic or recurrent infectious disease - Have received, or are expected to receive, any live virus or bacterial vaccination within 3 months before first administration of IP, or through Week 20 during the study. - Had a Bacillus Calmette-Guérin (BCG) vaccination within 1 year prior to screening. - History of positive human immunodeficiency virus (HIV), or have congenital or acquired immunodeficiency (eg, common variable immunodeficiency disease). - Active substance abuse or a history of substance abuse within 6 months prior to Screening. - Malignancy or history of malignancy, except for treated [ie, cured] basal cell or squamous cell in situ skin carcinomas and cervical intraepithelial neoplasia [CIN] or carcinoma in situ of the cervix with no evidence of recurrence within the previous 5 years. - Psoriasis flare or rebound within 4 weeks prior to Screening. - Topical therapy within 2 weeks of randomization or systemic therapy for psoriasis within 4 weeks prior to randomization - Use of phototherapy within 4 weeks prior to randomization or prolonged sun exposure or use of tanning booths or other ultraviolet (UV) light sources. - Any investigational drug within 4 weeks prior to randomization, or 5 pharmacokinetic/pharmacodynamic half lives, if known (whichever is longer). - Prior treatment with apremilast or etanercept.