Safety and Efficacy of Topically Applied CTA018 in Plaque Psoriasis

Inclusion Criteria: * clinical diagnosis of chronic plaque psoriasis for 6 months to a max 15% body surface area excluding face, scalp, groin, axillae, palms, soles of feet * at least two evaluable plaques with CPSS \>/= 6 * baseline PSGA \>/= 2 * women of childbearing potential msut agree to use an effective form of contraception Exclusion Criteria: * cannot have guttate, pustular, erythrodermic or other non-plaque forms of psoriasis * cannot have concomitant serious illness/condition that may interfere with participation in the study * cannot have used topical therapy within 2 weeks prior to baseline visit * cannot have used photo-therapy or systemic psoriasis therapy within 4 weeks prior to baseline visit * cannot have had prolonged exposure to natural or artificial UV radiation within 4 weeks of baseline visit or intend to have exposure during the study * cannot have used systemic immunomodulatory therapy within 12 weeks prior to baseline visit * cannot have a history of hypercalcemia or kidney stones * cannot be unable or unwilling to discontinue calcium and/or vitamin D supplementation during the study * cannot be pregnant or a nursing mother * cannot be participating in or have participated in an interventional study within 30 days of study start