[Calcipotriol].

Abstract

Calcipotriol is a vitamin D derivative synthesized in 1985 by the Léo Laboratories. Its mode of action is identical to that of 1-25 vitamin D3 (calcitriol), essentially by regulating the activity of genes capable of responding to vitamin D. Calcipotriol leads to reduction in keratinocyte proliferation and induces their differentiation as well as having important immunomodulator functions. Toxicology studies have demonstrated that phosphorus calcium metabolism anomalies are only observed for doses above those recommended for clinical use (100 g per week). The half-life of Calcipotriol is much shorter than that of calcitriol and its metabolites are inactive. The effects of Calcipotriol on phosphorus calcium metabolism are much less pronounced than those of calcitriol. Therapeutic trials in psoriasis have demonstrated the superiority of Calcipotriol over its excipient, class 2 dermatocorticoids, and reducers. Given in combination with phototherapy, cyclosporin or retinoids, Calcipotriol provides more complete improvement in lesions and allows a reduction in the cumulative doses of these treatments. Calcipotriol is effective in certain keratinization disorders (ichtyoses) as well as in localized sclerodermia and vitiligo, although the effect is less certain for the latter conditions. At recommended doses, adverse effects are limited to skin reactions with lesional and perilesional irritation in about 20 p. 100 of the cases. Contact dermatitis is rare. Photosensitivization can be observed when Calcipotriol is applied in patients undergoing UVB phototherapy. The marketing approval in France includes indications for psoriasis not involving more than 40 p. 100 of the skin surface. Several studies have demonstrated the efficacy and safety of Calcipotriol in children using the dose of 50 g per week per m2 body surface area. Contraindications include hypercalcemia, pregnancy and nursing. Three formulations are available (salve, cream, and lotion, all at 0.005 p. 100 concentration) for different administration schemes: two applications per day, alternative applications with dermocorticoid or in combination with systemic treatment for psoriasis. Long-term treatment protocols have not been determined.