Calcipotriol improves the response of psoriasis to PUVA

Combining PUVA with other therapeutic agents which reduce the UVA dose required for clearance of psoriasis may be of benefit by reducing the long-term risk of cutaneous malignancy and by increasing the efficacy of treatment. We have therefore studied the effect of calcipotriol in 13 patients with plaque-type psoriasis who were about to start twice weekly PUVA. In each patient, from the start of PUVA treatment, two plaques on symmetrical body sites were selected for assessment. Calcipotriol ointment was applied to one twice daily, and placebo to the other. Response was assessed weekly for 6 weeks: an investigator, unaware of treatment allocation, compared psoriasis severity within each of the plaques, and blood flux was measured using a scanning laser-Doppler velocimeter. Of the 11 patients who completed the study, in nine the calcipotriol-treated plaque either cleared before the placebo-treated plaque (n = 7), or was consistently judged to be better (n = 2). From the third week of the trial, mean blood flux was significantly lower in the calcipotriol-treated plaques than in those treated with placebo. In the seven patients whose psoriasis was clear in at least one plaque at the end of the study period, there was a median reduction in UVA dose of 26.5% for calcipotriol compared with placebo. With the exception of one patient, the improved response was not associated with earlier relapse.