INTRODUCTION
One of the biggest challenges in managing plaque
psoriasis is lack of adherence to treatments by patients,
which negatively affects treatment outcomes.1 Forty
percent of surveyed subjects with plaque psoriasis reported
nonadherence to their medication, which included under use
and over use.2 Frequently reported reasons for under use
included a lack of efficacy, staining of clothes or surfaces by the
medication, and time consuming application. Reasons for over
use included a desire for more rapid clearing of lesions, lack
of effectiveness, and perceived increase in efficacy. Therefore,
treatments with rapid efficacy that are easy to apply may help
improve patient adherence and, thereby, treatment outcomes.
Topical corticosteroids are the mainstay of treating plaque
psoriasis.3 Clobetasol propionate is a highly potent topical
corticosteroid available in a spray formulation that is indicated to
treat moderate to severe plaque psoriasis, and is the only class
1 topical steroid FDA-approved for up to 4 weeks of use.4-7 Multiple
studies, comprising over 2,200 subjects, have demonstrated that
clobetasol propionate 0.05% spray (CPS) is a safe and effective
regimen for treating moderate to severe plaque psoriasis as a
monotherapy or in combination therapy.8-10 Over 78% of subjects
achieved treatment success (defined as a score of clear or almost
clear for overall disease severity [ODS] or target plaque severity)
at the end of the 4 week treatment period and subjects also
reported improvements in QoL.4-7 CPS has been highly rated by
subjects who felt it was easy to apply, was easily absorbed into
the skin, and did not stain clothing or skin.11
A post hoc analysis of week 1 data from the 2 pivotal CPS
trials demonstrated that a significant number of subjects
experienced improvements in the signs and symptoms of
plaque psoriasis (ODS, pruritus, plaque elevation, scaling, and
erythema) as early as 1 week after initiation of treatment.12 Early
improvement in signs and symptoms of plaque psoriasis after
1 week of treatment with CPS could improve patient adherence
and treatment outcomes.
While the previous analysis indicated that a patient is likely to
see improvements within a week of initiating treatment with
CPS, it is unknown how these improvements at week 1 relate
to improvements at week 4. Data from the 2 pivotal CPS trials
was modeled using a generalized linear model in an effort to
understand how improvements at week 1 affected treatment
success at week 4. The purpose of this present post hoc analysis
is to explore the predictive relationship between the response of
ODS or pruritus to CPS after 1 week of treatment and treatment
success of ODS after 4 weeks of treatment.
METHODS
Clobetasol Propionate 0.05% Spray Pivotal Studies
Two identical multicenter, randomized, double-blind, vehicle
controlled, parallel group, phase 3 studies investigated the efficacy
and safety of CPS compared to vehicle spray for the treatment
of moderate to severe plaque psoriasis.5,7,13 Both studies were
conducted in accordance with the Declaration of Helsinki, Good
Clinical Practices, and all other applicable regulations.
