The purpose of this study is to test the safety and effectiveness of infliximab in patients with plaque psoriasis who have been receiving the drug etanercept for treatment of their plaque psoriasis for at least four months, without enough improvement in their psoriasis symptoms.

The most common form of psoriasis is plaque-type psoriasis, which is characterized by recurrent flaring of thickened, red, scaly patches of skin.

Although psoriasis is usually not life threatening, these physical discomforts combined with the potential psychological effects of the disease may interfere with everyday activities and negatively impact an individual's quality of life. Infliximab is an antibody made in a laboratory. Antibodies are proteins that fight other substances in the body that may cause infections or diseases. A substance called "tumor necrosis factor" (TNF) naturally occurs in the body. TNF is related to the itchy patches of skin (or plaques) of psoriasis. Infliximab stops the TNF from working. Other studies have shown that stopping the TNF may reduce the plaques. To address the unmet medical need for effective chronic therapies, TNFalpha blockers have recently been used to treat patients with moderate to severe plaque psoriasis. Etanercept also works by stopping the TNF, but in a different way than infliximab. This multi-center, open-label study is designed to test whether or not patients with plaque psoriasis who have not responded well to etanercept treatment may benefit from treatment with infliximab. Key effectiveness measurements will include the time to onset of symptom improvement and health-related quality of life. Safety will be assessed throughout the study.

Two weeks after their last dose of etanercept, all eligible patients will receive open-label 5 mg/kg infliximab infusions at Weeks 0, 2, 6, 14, and 22.

Inclusion Criteria:

• Have plaque psoriasis despite at least 4 months of treatment with etanercept per current product labeling
• Have psoriatic target lesions that have a PGA score greater than 1 (minimal) at screening
• If receiving methotrexate at screening, must have received methotrexate for at least 3 months and at a stable dose of <= 25 mg/week for at least 4 weeks prior to screening
• If receiving cyclosporine at screening, must have received cyclosporine at a stable dose of <= 5 mg/kg daily for at least 4 weeks prior to screening

Exclusion Criteria:

• Have already received infliximab or adalimumab
• Have shown a previous immediate hypersensitivity response, including anaphylaxis, to an immunoglobulin product
• Have a history of latent or active granulomatous infection, including tuberculosis, histoplasmosis, or coccidioidomycosis, prior to screening
• Have a concomitant diagnosis or any history of Congestive Heart Failure
• Are pregnant, nursing, or planning pregnancy
• Have used systemic corticosteroids within the 4 weeks prior to screening
• Have used topical corticosteroids or have initiated treatment with other topical therapies that could affect psoriasis or Psoriasis Area and Severity Index (PASI) evaluation (e.g., tar, anthralin, calcipotriene, tazarotene, methoxsalen) within 2 weeks prior to screening
• Have used new systemic agents/treatments, other than methotrexate, that can affect psoriasis including, but not limited to, immunosuppressants and/or psoralen plus ultraviolet A light (PUVA) within the 4 weeks prior to screening