A comparative study of calcipotriol and anthralin for chronic plaque psoriasis in a day care treatment center.

Abstract

Eighteen patients with symmetric plaque-type psoriasis were recruited for an open, controlled, bilateral half-body comparison study to evaluate the efficacy of calcipotriol/tar/UVB vs. anthralin/tar/UVB in a day care treatment setting. No patient had been on systemic antipsoriatic agents for at least 3 months prior to enrolment. One half-body was arbitrarily assigned to treatment with gradually increasing concentrations of anthralin as tolerated. The other half-body received calcipotriol ointment twice daily. Both sides received UVB and additional coal tar distillate in accordance with our standard day care regimen. Patients who were admitted to the day care program attended the clinic for UVB, anthralin, and calcipotriol on weekdays for two consecutive weeks. Anthralin was applied to psoriatic plaques on one side in the following fashion: anthralin 0.1% with salicylic acid 3% in zinc oxide paste on days 1 and 2; anthralin 0.2% with salicylic acid 3% in zinc oxide paste on days 3-5; anthralin 1% with salicylic acid 3% in hydrophilic petrolatum for 60 min on days 8-10 to thicker lesions; and anthralin 2% with salicylic acid 3% in hydrophilic petrolatum for 60 min on day 11 to thicker lesions. On the contralateral side, calcipotriol ointment 0.05 microgram/mL (Leo Pharmaceuticals, Ajax, Ontario) was applied to lesions twice daily. No anthralin or calcipotriol was applied on weekends. All patients applied coal tar oil 50% (Doak Oil Forte, Trans CanaDerm, St-Laurent, Québec, equivalent to 5% coal tar distillate) with salicylic acid 5% in hydrophilic petrolatum to their lesions at home in the evenings and on weekends. UVB (FSX72T12 lamps, National Biologic Corporation, Twinsburg, Ohio) was administered twice daily on weekdays in increasing doses as tolerated (to erythema) prior to the application of the topical medications. No trial medications were applied to the face, scalp, or genital regions. For clinical evaluation, the standard Psoriasis Activity and Severity Index (PASI) score was modified by splitting the score for area under 10%; the modified score (mPASI) for an area of coverage of 1%-4% was 0.5 and for an area of 5%-9% was 1. The head and neck area was excluded from the analysis since neither anthralin nor calcipotriol was used at these sites. Each half-body was considered to represent 100% in the area score determination. The maximum modified score for each side was 64.8 (vs. 72 in the standard PASI scoring system). Clinical evaluations were completed at days 0 (baseline), 3, 7, 10, and 42. The primary end-point was day 10. On day 10, patients were asked to compare the calcipotriol ointment to the anthralin on a five-point scale in terms of efficacy and irritancy and to state their future preferred treatment modality. Following discharge from day care, patients were continued on outpatient UVB and tar treatments three times weekly and asked to return for a repeat clinical assessment after 4 weeks (day 42). Blood samples taken prior to treatment and at day 10 were analyzed for serum calcium. Comparisons of treatment efficacy were based on changes in the mPASI scores from onset of treatment to day 10, as well as on the corresponding percentage changes. Analyses were carried out using the Wilcoxon test. Subjective patient comparisons of effectiveness and irritancy, as well as patient preference, were tested for equiprobability using the chi-square goodness-of-fit test with an examination of the adjusted residuals.