- Subjects previously treated with MTX or infliximab; subjects who are taking specific drugs within the specified time frame prior to Baseline as follows: any therapeutic agent targeted at reducing tumor necrosis factor (TNF) or any biologic, live virus or bacterial vaccinations within 3 months; any systemic medications or treatments that could affect psoriasis or PASI evaluations, or any systemic immunosuppressants or lithium within 4 weeks; any topical medications or treatments that could affect psoriasis or PASI evaluations within 2 weeks. The only allowed topical treatments for psoriasis are shampoos (containing tar or salicylic acid only) and topical moisturizers. Subjects should not use these topical agents during the morning prior to a study visit. Non-medicated shampoos may be used on the morning of a visit.