Betamethasone Dipropionate Spray 0.05% Alleviates Troublesome Symptoms of Plaque Psoriasis
Patients consider pruritus and scaling to be the most bothersome symptoms of psoriasis. Psoriatic plaques on the knees and elbows are widely considered difficult to treat because of the thicker stratum corneum, which reduces skin hydration and topical absorption. Betamethasone dipropionate (BD) spray 0.05% is a topical steroid with demonstrated efficacy in treating plaque psoriasis. Post hoc analyses of 2 phase 3 trials were done to assess the efficacy of BD spray in relieving the symptom of itching and improving the signs of erythema, scaling, and plaque elevation on plaques located on the knees and elbows vs its vehicle and an augmented BD (AugBD) lotion 0.05%. Betamethasone dipropionate spray reduced the incidence of pruritus, with approximately half of patients who reported itching at baseline showing complete itch relief by day 4. Betamethasone dipropionate spray also reduced the signs of psoriasis on knee and elbow plaques in more patients than AugBD lotion at day 4, though the differences were not statistically significant. Efficacy was similar between the 2 formulations on days 8 and 15. Betamethasone dipropionate spray rapidly relieved2 of the most bothersome symptoms of psoriasis and improved psoriatic signs in hard-to-treat knee and elbow plaques.
Practice Points
- Pruritus is one of the most bothersome symptoms of psoriasis; plaques located on the knees and elbows remain hard to treat.
- Topical corticosteroids are the initial form of treatment of localized plaque psoriasis.
- The choice of vehicle can change the penetration of the medication, alter the efficacy, and minimize side effects of the drug.
- Betamethasone dipropionate spray 0.05% is a mid-potent corticosteroid that provides fast symptom relief and early efficacy in clearing plaques, similar to a high-potency topical corticosteroid but with less potential for systemic absorption and adverse events.
Assessments
Two post hoc analyses were conducted on data pooled from the 2 phase 3 trials: (1) incidence of itching, and (2) total sign score (TSS) for lesions located on the knees and elbows.
Itching
Itching was assessed proactively by asking patients if they were experiencing itching (yes/no) at each visit (baseline and days 4, 8, 15, and 29) or had experienced itching since their last visit. As itching could be an adverse event of topical application, application-site pruritus was also recorded.
Total Sign Score
For each patient, a target plaque was selected that was representative of their psoriasis. The plaque was assessed on a 3-point grading scale for each of 3 key signs of plaque psoriasis: erythema, scaling, and plaque elevation (Table 1) at baseline and days 4, 8, 15, and 29. Total sign score was calculated by summing the scores for these 3 signs, resulting in a score ranging from 0 to 9. Treatment success was measured as (1) achieving a score of 0 or 1 (ie, reducing the plaque to clear or slight to mild) for the individual signs of erythema, scaling, and plaque elevation; and (2) achieving a TSS of 0 or 1 for all 3 signs—erythema, scaling, and plaque elevation—for each target lesion. Total sign score was assessed proactively for all patients.15,16 The post hoc analysis reported here examined patients whose target lesion was located on either the knee or the elbow.
Statistical Analyses
Because both study protocols were identical, data were pooled from the 2 phase 3 trials. All statistical analyses were performed using SAS software (SAS Institute). Two-sided hypothesis testing was conducted for all analyses using a significance level of P=.05. Post hoc analyses used Fisher exact test. No imputations were made for missing data.
Statistical analyses of itching compared the incidence of itching at each assessment time point (baseline and days 4, 8, 15, and 29) between BD spray and vehicle and between BD spray and AugBD lotion. Additional analysis included a statistical test on the incidence of itching in the subgroup of patients who reported itching at baseline.
Statistical analyses for the knees and elbows included only patients with their target lesion located on either the knee or the elbow. Analyses compared BD spray with vehicle and BD spray with AugBD lotion at days 4, 8, 15, and 29. Comparison with AugBD lotion treatment was up to day 14 only, consistent with application time limits in the AugBD lotion product label.18
