A MULTICENTER, PARALLEL-GROUP COMPARISON OF CALCIPOTRIOL OINTMENT AND SHORT-CONTACT DITHRANOL THERAPY IN CHRONIC PLAQUE PSORIASIS

Short-contact treatment with dithranol (anthralin) is a widely used treatment for chronic plaque psoriasis. Although effective, it causes staining and irritation, and is therefore inconvenient. Calcipotriol is a recently developed vitamin D analogue which is effective and easy to use. To evaluate the relative efficacy, safety and acceptability of these treatments a multicentre, open, randomized, parallel-group comparison was performed. Four hundred and seventy-eight patients with chronic plaque psoriasis were randomized to use one of the two treatments for 8 weeks. One group applied calcipotriol ointment (50-mu-g/g) twice daily. The other used a single application for 30 min each day of Dithrocream(R) in the highest concentration tolerated. Severity of psoriasis was assessed by modified PASI score at baseline, and after 2, 4, and 8 weeks of treatment. A five-point scale was used by subjects and by investigators as an additional assessment of overall response, and a similar scale was used by subjects to grade acceptability. Total serum calcium was monitored at baseline and after 2 and 8 weeks on treatment. The mean PASI score fell from 9.1 to 4.7 after 8 weeks on dithranol (P < 0.001), and from 9.4 to 3.4 on calcipotriol (P < 0.001). The difference between the two treatments was significant in favour of calcipotriol at 2 weeks (P < 0.001), and remained so at subsequent assessments. At 8 weeks the difference between mean improvements in scores for the two groups was 1.6 (95% confidence interval 0.5-2.7). Efficacy grading by subjects and investigators, and acceptability grading by subjects, were all significantly better for calcipotriol. The mean serum calcium showed no increase in either group. Calcipotriol was more effective and better accepted than short-contact dithranol. Both treatments appeared free from serious adverse effects.