This is a 12 week bilateral study, consisting of 6 weeks of treatment and 6 weeks of follow-up. The purpose of the study is to compare the safety and effectiveness of combining and then following a high potency topical corticosteroid treatment with LCD treatment for moderate-to-severe localized plaque psoriasis.

Superpotent topical corticosteroids such as clobetasol propionate are highly effective in treating plaque psoriasis but are not indicated for long term use due to their side effects. Therefore, steroid-sparing combination and sequential regimens, in which the corticosteroid gets supplemented with a non-steroid medication, such as calcipotriol or tazarotene, have become the standard of care, especially in the management of localized psoriasis lesions. A new steroid-free 15% liquor carbonis distillate (LCD) solution (Psorent) was recently found to be more successful than 0.005% calcipotriol cream (Dovonex) at improving and delaying worsening of psoriasis symptoms in a controlled clinical trial. The goal of this pilot study is to evaluate if this LCD solution can be used in combination with acute topical corticosteroid therapy as a new steroid-sparing / enhancing regimen. We hope to explore the compatibility, patient tolerability, and clinical benefit of using LCD solution during and after treatment with clobetasol propionate in adults with moderate to severe plaque psoriasis. This is a randomized, double-blind, vehicle-controlled, bilateral study. Men and women 18 years of age or older, with chronic plaque psoriasis affecting less than or equal to 10% body surface area (BSA) in areas other than the scalp, face, palms, soles, axillae, and groin, are recruited. Those with a Physician Global Assessment (PGA) score greater than 3 and are in general good health will qualify as candidates. On one side of the body, LCD solution and clobetasol propionate will be administered twice daily for the first 2 weeks of treatment, followed by 4 weeks of LCD solution only, followed by 6 weeks of no treatment. On the second half of the body, subject will apply a vehicle solution and clobetasol propionate twice daily for the first 2 weeks, only the vehicle solution twice daily for the next four weeks, and then no treatment for the next 6 weeks. Subjects will be evaluated at weeks 2, 4, 6, 8, 10 and 12. investigators will use the PGA scale [Clear (0) - Severe (5)] to determine treatment effects as well as Target Lesion assessments of Erythema, Scaling, Induration and overall severity [None (0) - Very Severe (4)]. patients will also be required to complete Self-Assessment questionnaires on their psoriasis [None (0) - Severe (6)]. as well as an assessment of the study solution [Excellent (9) - Poor (1)]. . Photographs will be taken at each study visit and adverse events will be monitored throughout the study.

Inclusion Criteria:

• 18 years of age or older
• able to provide written informed consent
• able to attend study visits, apply medications, and follow instructions
• moderate to severe localized plaque psoriasis lesions (<10% BSA on each side of the body)

Exclusion Criteria:

• other current treatments for psoriasis
• hypersensitivity to steroids, liquor carbonis detergens, alcohol, fragrance
• pregnant or nursing

Fifteen patients with localized chronic plaque psoriasis (less than or equal to 6% BSA and PGA score greater than or equal to 3) were enrolled. Eleven patients completed the study. Three patients were removed due to an adverse event, and 1 patient was lost to follow-up after week 2.

Adverse event information was monitored throughout the entire 12 week study.

This was a bilateral study in which 15 subjects total were recruited and randomized to receive both interventions simultaneously by dividing treatment arms to each side of the body.