Efficacy of topical treatment in psoriasis with MC903, a new vitamin D analogue.

In 10 in-patients with chronic plaque psoriasis, the antipsoriatic effect of MC903, a new synthetic analogue of vitamin D was evaluated. In each patient two symmetrical located psoriatic plaques were selected for the study. Topical treatment with MC903 cream (containing 1.2 mg MC903 per g cream) was compared with placebo cream in a double-blind, controlled, left-right, randomized way during 6 weeks of therapy. Compared with baseline, the clinical (erythema, scaling and infiltration) improvement was significant after 1 week of therapy with MC903 cream, while lateral comparison showed MC903 cream significantly better than cream base after 4 weeks of therapy (p less than 0.05). Measurements of skin blood flow by the laser Doppler technique in evaluating the disease activity was not superior to the clinical assessments. In 3 patients the psoriatic lesions treated with MC903 cream cleared completely during 6 weeks of therapy. No essential adverse reactions were observed. MC903 has a potent effect on cell proliferation and cell differentiation, but has minimal effect on calcium metabolism. It is concluded that this synthetic vitamin D analogue is potentially useful in the treatment of psoriasis.