Improvement in Signs and Symptoms of Plaque Psoriasis After 1 Week of Treatment With Clobetasol Propionate 0.05% Spray

December 2012 | Volume 11 | Issue 12 | Original Article | 1455 | Copyright © December 2012


Robert Brodell MDa,b and Norman Preston PhDc

aDivision of Dermatology, University of Mississippi Medical Center, Jackson, MS bDepartment of Dermatology, University of Rochester School of Medicine and Dentistry, Rochester, NY cGalderma Laboratories, L.P., Fort Worth, TX

Abstract
Clobetasol propionate 0.05% spray (CPS) is a topical, super-high-potent corticosteroid indicated for the treatment of moderate to severe plaque psoriasis. Two pivotal trials of CPS investigated the efficacy and safety of treatment in subjects with moderate to severe plaque psoriasis. Overall disease severity (ODS), erythema, plaque elevation, scaling, and pruritus were assessed on a 5-point scale of 0 (clear) to 4 (severe/very severe). Overall disease severity treatment success was defined as achieving a score of ≤2 at week 2 and a score of ≤1 at week 4. Treatment success for all other parameters was defined as achieving a score of ≤1 at all time points. Based on Cochran-Mantel-Haenszel analysis, treatment success was achieved in the CPS group in both studies compared with vehicle after 2 weeks, but not after 1 week. Only subjects who achieved treatment success were considered for analysis. Thus, subjects who did not meet the criteria for treatment success were not examined for improvement. A post hoc analysis was conducted using all the data and the median as the measure of central tendency. It was shown that ODS, erythema, plaque elevation, scaling, and pruritus improved by 1 grade from baseline at week 1 in subjects given CPS. The data presented here suggest CPS is effective in improving the signs and symptoms of plaque psoriasis 1 week after initiating treatment.

J Drugs Dermatol. 2012;11(12):1455-1459.

INTRODUCTION

Plaque psoriasis is a chronic inflammatory disease of the skin affecting approximately 2% of the US population.1 The physical signs of plaque psoriasis (erythema, scaling, dryness, pigmentary changes, and plaque elevation) and associated symptoms (pruritus, burning, tenderness, and pain) can profoundly affect quality of life (QOL). Physical and mental functioning in these subjects is comparable with those afflicted with other serious ailments, including depression, heart disease, and cancer.2 No cure for psoriasis exists. Treatment relies on management of the disease utilizing topical therapies, traditional systemic agents, and biologic drugs.
Clobetasol propionate is a superpotent topical corticosteroid indicated for moderate to severe plaque psoriasis. It is generally well tolerated and is available in several formulations, including a spray.3-6 Clobetasol propionate 0.05% spray (CPS) was an effective treatment for plaque psoriasis in clinical trials comprising more than 2,200 subjects.7 In these trials, treatment was successful (clear or almost clear in the overall disease severity [ODS] scale or in the target plaque severity scale) in more than 78% of subjects at the end of the 4-week treatment period.3-6 Quality of life, as measured by the PQOL-12 psoriasis QOL portion of the Koo-Menter Psoriasis Instrument and the Dermatology Life Quality Index, also improved in subjects treated with CPS.6,8,9 Because of the risk of adverse events with prolonged use, super-high-potent topical corticosteroid agents are usually limited to 2-week treatment periods. These studies, however, demonstrated that CPS is safe and effective over a 4-week period, with most patients treated with CPS achieving excellent results after just 2 weeks.3-6
In 2 pivotal trials that established the efficacy and tolerability of CPS in plaque psoriasis, measurements of efficacy were dichotomized into success or failure, and the Cochran-Mantel-Haenszel (CMH) analysis was used to compare treatment success between the treatment groups.4,10 Significant success in treatment (clear or almost clear) was achieved in ODS in the CPS group in both studies compared with the vehicle group after 2 weeks, but not after 1 week. Reexamination of the distribution of scores at week 1 revealed a shift toward more rapid improvement in the CPS groups. This raised the question whether dichotomizing the scores into success or failure rates had masked improvements in the distribution of scores that were otherwise lost. In fact, dichotomizing scores into success or failure and analyzing using the CMH test masks more gradual improvements in the distribution of scores not categorized as success. Subjects who did not achieve success in ODS by week 1 may have demonstrated significant improvements in ODS and in individual sign/symptom scores (erythema, plaque elevation, scaling, and pruritus) from baseline. Thus, the CMH test may not be the most appropriate analytic tool if the percentages of success are near 0% or 100%.11
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