- Subject has at least 2 stable plaques assessed at Screening and Day -1. One of a suitable size and in a site suitable for repeat biopsy, and one for index lesion Plaque Lesional Severity Score (PLSS) scoring. Both must have a PLSS lesional score of >=2 for the induration component (moderate or above), >=1 for erythema and scaling with a total score of >=5. The biopsy lesion must not be on the face, groin or scalp and must be protected from the sun