Approximately 2 percent of adults in the United Kingdom are affected by psoriasis. The condition cannot be cured. Although many treatment options are available to control symptoms and minimize the impact of psoriasis on daily activities, effective treatment of patients with psoriasis remains a challenge. Currently, calcipotriol (a synthetic vitamin D₃ analog) is one of the most popular topical treatments in the United Kingdom for this condition. Ashcroft and colleagues reviewed the evidence of efficacy of this agent in the treatment of patients with mild to moderate chronic plaque psoriasis.

A quantitative, systematic search was conducted of electronic databases for randomized controlled trials of calcipotriol. Information was also requested from the drug manufacturer. Of the 62 trials identified, 37 trials involving more than 6,000 patients were included in the analysis. Overall, eight placebo-controlled trials involving 1,185 patients compared calcipotriol to placebo. At eight weeks, calcipotriol was more effective than placebo in adults. The results from one of these trials revealed that calcipotriol was no more effective than placebo in children. Results from two of the eight trials that compared calcipotriol to potent topical corticosteroids revealed that calcipotriol was as effective in reducing the area of skin involvement and the severity of psoriasis after six weeks; however, at eight weeks, the corticosteroids were more effective. Calcipotriol was as effective as highly potent topical corticosteroids in two trials, but a combination of a potent corticosteroid plus calcipotriol was more effective than calcipotriol monotherapy. Results from one study reported that calcipotriol was superior to many common treatments for psoriasis (e.g., tacalcitol, coal tar and combined coal tar 5 percent, allantoin 2 percent and hydrocortisone 0.5 percent). No difference was found between calcipotriol and ultraviolet B phototherapy. Two trials compared calcipotriol in once-daily versus twice-daily dosage; better results were obtained with the twice-daily application. Adverse effects of calcipotriol included lesional or perilesional irritation, irritation of the scalp or face, or exacerbation of psoriasis; however, skin irritation rarely led to withdrawal from calcipotriol treatment.

The authors conclude that calcipotriol is an effective treatment in patients with mild to moderate chronic plaque psoriasis and is more effective than many alternative medications, including several forms of steroids. Only highly potent topical corticosteroids provide comparable efficacy after eight weeks of therapy. While calcipotriol therapy avoids the many potential adverse effects of corticosteroids, it is associated with skin irritation in a greater number of patients.