The percentage of subjects who achieve a reduction of 75% or greater from Baseline in the Psoriasis Area and Severity Index (PASI-75) The PASI is a measure of the average redness, thickness, and scaliness of the lesions (each graded on a 0-4 scale) and is weighted by the area of involvement. The minimum possible score on this scale is '0', while the maximum score on this scale is 72. A lower score on this scale at the end of the study indicates an improvement in the condition of subject.

The Percentage of subjects who achieve the Investigator's Global Assessment (IGA) score of clear or almost clear (IGA score 0 or 1) Score Grade Definition 0 Clear: No signs of psoriasis 1. Almost clear: No thickening to minimal plaque elevation; Normal to slight pink coloration/faint erythema; Focal to minimal scaling 2. Mild: Slight elevation/thickening; Pink to light red coloration; Predominantly fine scaling partially or mostly covering lesions 3. Moderate: Clearly distinguishable/distinct thickening; Definite red coloration; Coarse scaling covering most plaques 4. Severe: Marked thickening with hard/sharp edges; Bright to deep dark red coloration; Thick/coarse scaling covering almost all or all lesions A lower score on this scale at the end of the study indicates an improvement in the disease condition.