Clinical finding shows that twice daily administrations of 2 mg of 1-deoxy-1-[N6-(3-iodobenzyl)-adenin-9-yl]-N-methyl-&bgr；-D-ribofuronamide (IB-MECA) (total daily administration of 4 mg) 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 8 mg, respectively). A pharmaceutical composition for the treatment of psoriasis includes 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 including an administration dose of 2 mg.
