- Stable, moderate to severe plaque psoriasis in at least three distinct plaque areas, each separated by at least a 2.5-cm band of normal skin. Study plaque areas, each covering a contiguous area up to 15 x 35 cm in size, should have a minimum plaque size of 2 cm2. All study plaque areas must be on the trunk or extremities (excluding palms, soles, scalp, and facial or intertriginous sites).