Etretin therapy for severe psoriasis. Evaluation of initial clinical responses.

We have investigated the clinical responses of 21 patients with severe psoriasis to therapy with etretin, a metabolite of etretinate. In a preliminary double-blind dose-finding study, the optimum dose of etretin was determined to be 50 mg/d (mean, 0.66 mg/kg/d). In an open study, patients receiving etretin therapy were followed up for a minimum of six months. An excellent or good response (greater than 50% clearance) was obtained in 18 of 21 patients. The incidence of mucocutaneous side effects from etretin therapy was similar to that previously reported with etretinate therapy. As a group, patients who received etretin therapy for six or more months showed no significant aberrations from normal levels of serum lipids or serum liver enzymes. However, five patients had mild elevation of liver enzymes or blood lipids, which were corrected by dose reduction. Etretin showed equivalent efficacy to that previously reported with etretinate in severe recalcitrant plaque psoriasis vulgaris. Taken with the reportedly more rapid clearance of etretin from the body, there may be clinical advantages of the use of etretin over the use of etretinate.