Long-term continuous versus intermittent cyclosporin: therapy for psoriasis.

A multicenter randomized controlled study was conducted to assess the long-term efficacy and safety of cyclosporin A therapy for psoriasis using either a continuous or an intermittent regimen. Initially, both regimens consisted of 3-5 mg/kg/day administration of CyA. Once remission was obtained, CyA dose was maintained between 0.5 and 3 mg/kg/day under the continuous regimen, while under the intermittent regimen, CyA dose was tapered off and, when necessary, topical corticosteroids were used until relapse occurred. Thirty-one patients were followed for at least 48 months (mean follow-up period: 55.9+/-4.6 months): 15 received continuous therapy, and 16 received intermittent therapy. With both regimens, the PASI (Psoriasis Area and Severity Index) score was maintained at 5-12 points throughout the follow-up period. The score was decreased by more than 70% from baseline with both regimens: the responses between them were not significantly different. However, overall control of psoriasis, as assessed from the averaged PASI score, was better in the patients receiving continuous therapy. Although the overall frequency of adverse reactions was similar for the two regimens, cancer occurred in two patients on continuous therapy (gastric cancer and hepatocellular carcinoma in one patient each). We could not, however, definitely attribute the cancers in the two patients to continuous therapy itself. There was a significantly higher incidence of renal impairment in elderly patients receiving either regimen when compared with younger patients. In conclusion, CyA administered to psoriasis patients under both regimens exhibited long-term efficacy and tolerability. Despite a lower overall efficacy, it seems proper to conclude that intermittent therapy is more useful than continuous therapy due to the occurrence of malignancies with continuous therapy. Further investigation is required to determine whether intermittent therapy is really safer than continuous therapy, and, if so, how it should be designed to minimize long-term adverse reactions and achieve overall control comparable to that of continuous CyA therapy.