• Dermatology Live Quality Index (DLQI) response at week 12
• Subject's assessment of itching and improvements from baseline in joint pain (visual analog scale [VAS]) at week 12
• Psoriasis pain (VAS) at week 12
• Functional Assessment of Chronic Illness Therapy (FACIT) fatigue scale at week 12
• PASI 50, 75 and 90 response and improvement from baseline in PASI score during long-term therapy
• Static physician's global assessment of psoriasis (sPGA) from baseline during long-term therapy
• Adverse events, infections injection site reactions during long-term therapy
• Serious adverse events and infections during long-term therapy
• Clinical laboratory values, vital signs and antibodies to etanercept during long-term therapy

The purpose of this study is to determine the effect of etanercept 50 mg twice weekly compared to placebo over 12 weeks on the psoriasis area and severity index (PASI) in subjects with psoriasis. This study will also evaluate the safety and tolerability of etanercept 50 mg twice weekly; determine the effect of etanercept 50 mg twice weekly on patient reported outcomes (PRO); and characterize the pharmacokinetics (PK) profile of etanercept 50 mg twice weekly.

• Tyring S, Gottlieb A, Papp K, Gordon K, Leonardi C, Wang A, Lalla D, Woolley M, Jahreis A, Zitnik R, Cella D, Krishnan R. Etanercept and clinical outcomes, fatigue, and depression in psoriasis: double-blind placebo-controlled randomised phase III trial. Lancet. 2006 Jan 7;367(9504):29-35.
• Tyring S, Gordon KB, Poulin Y, Langley RG, Gottlieb AB, Dunn M, Jahreis A. Long-term safety and efficacy of 50 mg of etanercept twice weekly in patients with psoriasis. Arch Dermatol. 2007 Jun;143(6):719-26.
• Krishnan R, Cella D, Leonardi C, Papp K, Gottlieb AB, Dunn M, Chiou CF, Patel V, Jahreis A. Effects of etanercept therapy on fatigue and symptoms of depression in subjects treated for moderate to severe plaque psoriasis for up to 96 weeks. Br J Dermatol. 2007 Dec;157(6):1275-7. Epub 2007 Oct 4. No abstract available.

Inclusion Criteria: - Active, but clinically stable, plaque psoriasis involving greater than or equal to 10% of the body surface area - A minimum PASI score of 10 obtained during the screening period Exclusion Criteria: - Active guttate, erythrodermic, or pustular psoriasis at the time of the screening visit - Evidence of skin conditions at the time of the screening visit (e.g., eczema) that would interfere with evaluations of the effect of an investigational product on psoriasis