- All systemic psoriasis medications, including psoralen long-wave ultraviolet radiation treatments, or other systemic immunosuppressives, are not allowed within 5 half lives prior to Day-1 (Methotrexate and cyclosporin are not allowed within 8 weeks of Day -1; Psoralen long-wave Ultraviolet (UV) is not allowed within 4 weeks of Day-1). Subjects should not be included if the investigator considers that the subject is at high risk of requiring rescue with prohibited medication for duration of study up to follow-up. This assessment should be based on current disease activity or a history of frequent and/or severe flares requiring systemic immunosuppression.