Phase 3b Safety and Efficacy Study of Apremilast to Treat Moderate to Severe Plaque-plaque Psoriasis

Inclusion Criteria: * 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 Exclusion Criteria: * 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 thro…