Calcipotriol versus coal tar: a prospective randomized study in stable plaque psoriasis

Abstract

Background: Topical therapies are the first line of treatment for patients with stable plaque psoriasis (SPP) affecting a limited body surface area. Very few trials comparing newer agents, such as 0.005% topical calcipotriol, with conventional modes of therapy, such as coal tar ointment, have been reported.

Methods: A prospective, right-left randomized, investigator-blinded study with a 12-week treatment period and an 8-week follow-up period was performed. Thirty-six patients with nearly bilaterally symmetrical SPP lesions on the limbs were instructed to apply 5% coal tar ointment overnight on one side once daily and 0.005% calcipotriol ointment on the other side twice a day. All patients were advised to expose both sides to the sun for 2 h every day. Psoriatic lesions and progress during treatment were evaluated using the severity (0-3) scale of erythema, scaling and induration (ESI score). Evaluation was carried out every 2 weeks during the treatment period and monthly during follow-up. At the end of 12 weeks, patients with > 75% reduction in the ESI score were considered to be markedly improved, those with 51-75% reduction to be moderately improved, those with 26-50% reduction to be minimally improved and those with < 25% to be non-responders. Self-assessment by the patients regarding the efficacy and acceptability of the two modalities was on a five-point scale. Serum calcium, serum phosphate, total and differential serum proteins, 24-h urinary calcium and phosphate were monitored both at baseline and after completion of therapy.

Results: Thirty of the 36 recruited patients completed the study. The difference in clinical response between the two sides was statistically significant at 4, 6 and 8 weeks, with the percentage reduction in ESI score with calcipotriol being 65.7 +/- 12.2% compared with 45.8 +/- 16.6% with coal tar at 8 weeks (P < 0.01, t = 6.4). However, the difference in clinical response at 10 and 12 weeks between the two sides was not significant, with a mean reduction of 71.9 +/- 13.3% in ESI score on the calcipotriol-treated side compared with 69.4 +/- 15.4% with coal tar ointment (P > 0.05). In the follow-up period of 8 weeks, recurrence of lesions was noted in 10% of patients treated with calcipotriol compared with 16.7% in those treated with coal tar after an average period of 6 +/- 1.2 and 5 +/- 1.3 weeks, respectively (P > 0.05).

Conclusions: It was found that 0.005% calcipotriol ointment produced a faster initial response and had better cosmetic acceptability in patients, although after a long period of treatment, i.e. 12 weeks, 5% coal tar ointment had comparable efficacy. There was no statistically significant difference in the relapse rates between the two modalities.