Intralesional cyclosporine for psoriasis. Relationship of dose, tissue levels, and efficacy

BACKGROUND AND DESIGN--To avoid systemic side effects, topical and intralesional administration of cyclosporine has been used; however, only intralesional administration has been successful. To understand more about the dosing requirements and resultant tissue levels of intralesional cyclosporine, we injected psoriasis plaques in a double-blind fashion with three different concentrations of cyclosporine (17 mg/mL in seven patients, 10 mg/mL in 13 patients, and 2.5 mg/mL in 11 patients) or matching vehicle three times weekly for 4 weeks. RESULTS--Statistically significant improvement was observed in plaques treated with 17 mg/mL (P = .003) compared with vehicle-treated plaques; the improvements in plaques treated with 10 mg/mL (P = .078) and 2.5 mg/mL (P = .054) achieved marginal statistical significance compared with vehicle treatment. Four weeks after discontinuation of therapy, the change from pretherapy in plaques that had received 17 mg/mL of cyclosporine was statistically significantly better (P less than .0001) than that with vehicle treatment. A similar finding but of marginal statistical significance (P = .059) occurred in the plaques that had received 10 mg/mL of cyclosporine. Throughout the study, untreated psoriasis plaques did not improve. Transient pain was the most common side effect noted with both cyclosporine and vehicle injections. Tissue levels of cyclosporine tended to be highest in plaques receiving the 17-mg/mL concentration; blood levels of cyclosporine were low throughout the study.

--Intralesional cyclosporine requires a sufficient dosage to improve psoriasis, apparently by a local mechanism of action. Improvement may persist for 4 weeks or longer.