Chronic Plaque Psoriasis Study With Topical Formulation Of GW786034

Inclusion criteria: * Stable (2-3 months) chronic plaque psoriasis covering greater than 5% body surface area (as determined by PASI palm method). * Other than having chronic plaque psoriasis, subject is health and ambulatory. * Women will be eligible to enter the study if they are of non-child-bearing potential (i.e. physiologically incapable of becoming pregnant, including any female who is post-menopausal or surgically sterile). * Must have at least two clinically similar lesions with the following characteristics as deemed by the dermatologist: Moderate to severe in elevation (thickness), erythema, and scaling (with a total score of at least 6 for each target lesion, when assessed using a 0-4 PASI score). Located on the trunk, buttocks, thighs or upper arms. Are of a sufficient size that will allow the application of three occlusive patches. Exclusion criteria: * Guttate, erythrodermic, or pustular psoriasis. * Psoriasis is spontaneously improving. * Have had psoriasis that was unresponsive to adequately dosed (\> 10 weeks) cyclosporine. * Any systemic disorder or active skin disease (other than psoriasis) or subjects who present with scars, moles, tattoos, body piercings, sunburn in the test area. * History of congestive heart failure (NYHA Class 3 or 4), myocardial infarction, coronary artery bypass graft, percutaneous transluminal balloon angioplasty, cerebrovascular accident, chronic or intermittent oedema. * Blood pressure of greater than 150mmHg systolic and /or 95mmHg diastolic following triplicate measurements taken 5 minutes apart. * Presence of unstable or severe angina or coronary insufficiency. * Uncontrolled bacterial, viral, or fungal infection. * Congenital or acquired immunodeficiency. * History of malignancy within the last five years, except for surgically cured skin carcinoma or cervical dysplasia (CIN I-II). * An unwillingness of male subjects to use a condom/spermicide in addition to having their female partner use another form of contraception if the woman could become pregnant from the time of the first dose of study medication until 5 half-lives of the drug have elapsed following removal of the last dose of study medication. * An unwillingness of male subjects to abstain from sexual intercourse with pregnant or lactating women from the time of first dose of study medication until five half-lives or 5 days (whichever is longer) following removal of the last dose of study medication. * Prolonged exposure to the sun (or tanning beds) during the study. * Systemic anti-psoriasis therapy, including but not limited to: acitretin, cyclosporine, isotretinoin, infliximab, entercept, alefacept, oral steroids and psoralen during the 4 weeks prior to the first dose of study medication and throughout the study. * Concomitant use of phototherapy or photochemotherapy. * Concomitant use of lithium, antimalarials, interferons. * Systemic beta-blockers are permitted provided the dose is stable for four weeks before baseline and remains stable throughout the study. * Concomitant use of anti-arthritis therapies with known propensity for hepatotoxicity (i.e. diclofenac, gold, D-penicillamine, leflunomide). * Use of topical or intralesional treatments for psoriasis (e.g. mid- or high-potency topical corticosteroids) within 2 weeks prior to Day 1 and throughout the study, except for class VI or VII topical steroid treatments (Desonide, or 2.5% hydrocortisone) which will be allowed on the face. * Concomitant use of non-drug therapies (i.e. herbal products or alternative therapies) for psoriasis.