Enhanced vasoconstrictor potency of the fixed combination calcipotriol plus betamethasone dipropionate in an innovative aerosol foam formulation vs. other corticosteroid psoriasis treatments

BackgroundAn aerosol foam formulation of fixed combination calcipotriol 50 g/g (Cal) and betamethasone 0.5 mg/g (as dipropionate; BD) has been developed for psoriasis vulgaris treatment. ObjectiveTo compare Cal/BD aerosol foam pharmacodynamic activity with Cal/BD ointment and with other topical corticosteroids of different potencies by assessing vasoconstrictor potential. MethodsA Phase I, single-centre, investigator-blinded, vehicle-controlled, intra-individual comparison vasoconstriction study. Healthy volunteers received a single application on selected sites of: Cal/BD aerosol foam, clobetasol propionate 0.5 mg/g cream (CP; very potent), Cal/BD ointment (potent), fluocinolone acetonide 0.25 mg/g ointment (FA; moderately potent), BD aerosol foam and aerosol foam vehicle. A seventh untreated site acted as a negative control. Skin blanching was assessed by visual (primary response criterion) and colorimetric a* and L* measurements (secondary criteria), and was analysed over time (6-32 h post-application). ResultsThirty-five healthy volunteers were included. All active treatments led to significantly greater skin blanching than control. By visual assessment, skin blanching with Cal/BD aerosol foam was significantly less compared with CP cream [mean AUC(0-32) 2560 vs. 3831; mean difference = -1272; 95% confidence interval (CI): -1598, -945; P < 0.001], similar to BD aerosol foam (mean AUC(0-32) 2560 vs. 2595; mean difference = -35; 95% CI: -362, 292; P = 0.83) and significantly greater than Cal/BD ointment (mean AUC(0-32) 2560 vs. 2008; mean difference = 552; 95% CI: 225, 878; P = 0.001) and FA ointment (mean AUC(0-32) 2560 vs. 1981; mean difference = 578; 95% CI: 251, 905; P < 0.001). Colorimetric assessments a* and L* also indicated significantly reduced skin blanching with Cal/BD aerosol foam compared with CP cream. No adverse events (AEs) were reported. ConclusionCal/BD aerosol foam can be considered a more potent formulation than Cal/BD ointment and the moderately potent FA ointment, but less potent than the very potent corticosteroid, CP cream.