3. A diagnosis of stable plaque-type psoriasis vulgaris with at least one pair of symmetric lesions on either the trunk, arms, or legs that would serve as target lesions. Paired target lesions must be in similar anatomic locations (e.g., right and left elbows or right and left knees) and have roughly equivalent (no more than one point difference) modified Psoriasis Area Severity Index (PASI) scores. Each paired target lesions must have PASI scores equal to or greater than 7;