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

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.