The present invention is based on the clinical finding that twice daily administrations of 2 mg of 1-[N6-(3-iodobenzyl)-adenin-9-yl]-Beta-D-ribofuronamide (IB-MECA) (total daily administration of 4mg) to subjects having moderate to severe psoriasis, was significantly more effective in treatment of the psoriatic plaques than treatment of psoriasis at two administration doses of 1 mg or 4 mg (total daily doses of 2 or 8mg, respectively). Thus, the present invention provides a pharmaceutical composition for the treatment of psoriasis comprising as the active ingredient IB-MECA in an amount suitable for a total daily dose administration of about 4 mg. In one preferred embodiment IB-MECA is administered twice a day to a subject in need of psoriasis treatment, the pharmaceutical composition comprising an administration dose of 2mg.
