• F6-1;
  • 25(OH)2D3 ointment;
  • psoriasis vulgaris;
  • randomized controlled trial

Background  Vitamin D analogues are useful in topical therapy of psoriasis.

Objectives  To evaluate the effect of hexafluoro-1,25-dihydroxyvitamin D3 (F6-1,25(OH)2D3) in treatment of psoriasis.

Methods  Fifteen patients with plaque-type psoriasis were enrolled in a single centre double-blind, right/left comparison, placebo-controlled study, and received 0·1 g of petrolatum containing 5 µg of F6-1,25(OH)2D3 or 0·1 g of petrolatum (placebo) for 3 months. After completion of this double-blind study, a subset of these patients (n = 12) applied F6-1,25(OH)2D3 ointment (50 µg g−1 of petrolatum) to all their lesions (total area, 100–5000 cm2, mean area: 3300 m2) for 2 months as a single application at night.

Results  The mean severity score in the right/left-sided controlled topical F6-1,25(OH)2D3 (50 µg g−1) therapy group showed a decrease of 85%. In contrast, the mean severity score for the placebo-treated areas showed a decrease of 45% (P < 0·001). In the 12 patients who subsequently applied F6-1,25(OH)2D3 (50 µg g−1) ointment to all of their lesions, 91·6% showed moderate to excellent improvement. The mean Psoriasis Area and Severity Index score decreased by 44·9% (from 33·6 ± 15 to 18·5 ± 13). No effect on calcium homeostasis was noted. Adverse events included mild irritation in two patients that resolved during therapy.

Conclusions  Topical F6-1,25(OH)2D3 is a safe and effective once a day treatment for psoriasis.