The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease). PASI 75 response was defined as \>=75% improvement in PASI score when compared to the baseline score.

An adverse event is any unfavorable and unintended change in the structure, function, or chemistry of the body whether or not considered related to the study treatment.

An adverse event is any unfavorable and unintended change in the structure, function, or chemistry of the body whether or not considered related to the study treatment. Participants may be discontinued from study drug due to adverse events, but remain on the study.