This Phase 3 study has been designed to determine and compare the efficacy and safety of 000-0551 Lotion and Vehicle Lotion applied twice daily for two weeks in subjects with plaque psoriasis.

Inclusion Criteria:

• Subject has a clinical diagnosis of stable plaque psoriasis involving a minimum of 2% and no more than 12% affected body surface area.
• Subject has an Investigator's Global Assessment (IGA) score of at least three (moderate) at study start.
• If subject is a woman of childbearing potential, she must have a negative urine pregnancy test and agree to use an effective form of birth control for the duration of the study.

Exclusion Criteria:

• Subject has spontaneously improving or rapidly deteriorating plaque psoriasis.
• Subject has guttate, pustular, erythrodermic or other non-plaque forms of psoriasis.
• Subject has used any phototherapy (including laser), photo-chemotherapy or other forms of photo based therapy for the treatment of their psoriasis within 30 days prior to study start.
• Subject has used any systemic methotrexate, retinoids, systemic corticosteroids [including intralesional, intra-articular, and intramuscular corticosteroids], cyclosporine or analogous products within 90 days prior to study start.
• Subject has used any systemic biologic therapy (i.e., FDA-approved or experimental therapy) within five half-lives of the biologic prior to study start.
• Subject had prolonged exposure to natural or artificial sources of ultraviolet radiation within 30 days prior to study start or is intending to have such exposure during the study.
• Subject has used topical body (excluding the scalp) psoriasis therapy (including coal tar, anthralin, steroids, retinoids, vitamin D analogs) within 14 days prior to study start.
• Subject has used emollients/moisturizers on areas to be treated within four hours prior to clinical evaluation at study start.
• Subject is currently using lithium or Plaquenil (hydroxychloroquine).
• Subject is currently using a beta-blocking medication (e.g., propanolol) or angiotensin converting enzyme (ACE) inhibitor at a dose that has not been stabilized.
• Subject is pregnant, lactating, or is planning to become pregnant during the study.
• Subject is currently enrolled in an investigational drug or device study.
• Subject has used an investigational drug or investigational device treatment within 30 days prior to study start.
• Subject has been previously enrolled in this study and treated with a test article.