Use of a psoriasis plaque test in the development of a gel formulation of calcipotriol and betamethasone dipropionate for scalp psoriasis.

BACKGROUND: The efficacy and safety of calcipotriol plus betamethasone dipropionate ointment in the treatment of psoriasis vulgaris has consistently been demonstrated in several clinical trials. For treatment of scalp psoriasis, more convenient formulations are required. Therefore, new lipophilic alcohol-free gel formulations containing calcipotriol (50 µg/g) and betamethasone (0.5 mg/g; as dipropionate) (two-compound gels) for treatment of scalp psoriasis were developed. OBJECTIVE: To identify the optimal gel formulation by evaluating the antipsoriatic effect in a psoriasis plaque test model. METHOD: The use of a psoriasis plaque test enables investigation of the antipsoriatic effect of several formulations and compounds in a limited number of patients, and is a useful method for predicting treatment efficacy in psoriasis vulgaris. Five different gel vehicles were investigated in two plaque test studies. RESULTS AND CONCLUSION: The optimised two-compound gels showed superior antipsoriatic effect over marketed betamethasone dipropionate solution. The results suggest that use of the psoriasis plaque test early in the development process can improve the development of topical formulations for dermatological use and can be a beneficial tool for selecting the most promising formulations for further clinical studies in psoriasis vulgaris.

Comparison of the antipsoriatic effect and tolerability of calcipotriol-containing products in the treatment of psoriasis vulgaris using a modified psoriasis plaque test.

BACKGROUND AND OBJECTIVE: In 1972, Dumas and Scholtz developed the psoriasis plaque test to evaluate the potency of local corticosteroids. Through further modification of this method, the efficacy between antipsoriatic products can be differentiated. This method allowed for the simultaneous application of several products to different test sites in the same psoriasis patient. The objective of this current study was to compare the antipsoriatic effect of six topical products using a modified version of the original psoriasis plaque test with emphasis on the predictive capacity of this model. Validation of the use of immunohistochemical and histological scoring of biopsy material, in conjunction with clinical scoring, in the prediction of antipsoriatic effects was an additional objective. METHODS: This study was a single-centre, investigator-blinded, within-subject randomized, active- and vehicle-controlled, intraindividual comparison of six topical products in patients with psoriasis vulgaris. The products evaluated were calcipotriol ointment (50 µg/g); calcipotriol cream (50 µg/g); two-compound ointment (calcipotriol 50 µg/g; betamethasone dipropionate 0.5 mg/g); two-compound gel (calcipotriol 50 µg/g; betamethasone dipropionate 0.5 mg/g) [all in their marketed formulations]; an investigational ointment (calcipotriol 25 µg/g; hydrocortisone 10 mg/g); and a vehicle control. Psoriasis patients (≥18 years of age; n = 24) received simultaneous topical application of each of the products 6 days a week for a period of 21 days, at different test sites located on psoriasis plaques. Clinical assessment of the test sites was completed twice a week. Test site biopsies were taken at the final visit for histological analysis. The primary endpoint was the absolute change in total clinical score (TCS; erythema, scaling and infiltration) from baseline. RESULTS: For all products, the change in TCS correlated well with changes in histological and immunohistochemical values. The two-compound ointment and the two-compound gel both resulted in a large and significant reduction in TCS. Calcipotriol ointment and the calcipotriol/hydrocortisone ointment were less effective, although they were still more effective than the calcipotriol cream and the ointment vehicle. CONCLUSION: This study has demonstrated that the modified psoriasis plaque test can provide a relatively quick and effective method to evaluate the antipsoriatic effect of several topical treatments in small cohorts and that, by combining clinical scoring and histological assessment, a more accurate prediction of the antipsoriatic effect can be made. The two-compound formulations (ointment and gel) had a comparable antipsoriatic effect, which was superior to the other products tested. Furthermore, these data indicate that the gel formulation could provide an alternative effective treatment option to the well established two-compound ointment for psoriasis patients. CLINICAL TRIAL REGISTRATION: Registered as EudraCT no: 2007-005463-10.

Comparison of the effects of vitamin D products in a psoriasis plaque test and a murine psoriasis xenograft model.

The aim of the present study was to compare the effects of Daivobet and calcipotriol on clinical score and biomarker responses in a modified version of the Scholtz-Dumas psoriasis plaque assay. Furthermore, it was the aim to compare the effects of calcipotriol and betamethasone in the murine psoriasis xenograft model. Twenty four patients with psoriasis were treated topically once daily for three weeks, whereas the grafted mice were treated for four weeks. Clinical responses were scored twice weekly and biopsies were taken at the end of each study to analyse for skin biomarkers by histology and immunohistochemistry. The results clearly demonstrate effects on both clinical signs and biomarkers. In the patient study the total clinical score was reduced significantly with both Daivobet and calcipotriol. Both treatments reduced epidermal thickness, Ki-67 and cytokeratin 16 expression. T cell infiltration was significantly reduced by Daivobet but only marginally by calcipotriol. Both treatments showed strong effects on the epidermal psoriatic phenotype.Results from the xenograft model essentially showed the same results. However differences were observed when investigating subtypes of T cells.The study demonstrates the feasibility of obtaining robust biomarker data in the psoriasis plaque test that correlate well with those obtained in other clinical studies. Furthermore, the biomarker data from the plaque test correlate with biopsy data from the grafted mice.

Calcipotriol plus betamethasone dipropionate scalp formulation is effective and well tolerated in the treatment of scalp psoriasis: a phase II study.

BACKGROUND: There is a need for more effective therapy for scalp psoriasis. OBJECTIVE: To assess the efficacy and safety of a 2-compound scalp formulation including calcipotriol and betamethasone dipropionate in the treatment of scalp psoriasis. METHODS: Patients (n = 218) with scalp psoriasis were randomized to treatment with the 2-compound scalp formulation (n = 108) or betamethasone dipropionate in the same vehicle (n = 110). The treatments were applied once daily on the scalp for up to 8 weeks. RESULTS: The 2-compound scalp formulation showed a significantly higher efficacy than betamethasone dipropionate on the total sign score at the end of treatment (p = 0.042) and after 2 weeks (p = 0.005). CONCLUSION: The calcipotriol plus betamethasone dipropionate scalp formulation was superior to betamethasone dipropionate in the same vehicle when used once daily for up to 8 weeks in the treatment of scalp psoriasis.