Object Mizoribine (MZR), imidazole nucleotide, inhibits purine synthesis and helper T cell functions. It is used as an immunosuppressant in chronic rheumatic arthritis in Japan. Twenty-four patients with relapsing-remitting and chronic progressive multiple sclerosis (MS) were studied for the long-term effects of MZR over 8 years. Methods Average daily MZR doses of 200 mg along with prednisolone (PSL) were administered in the patients studied. Ten of 24 patients were treated for more than 5 years. Results The mean relapse rate per year at entry (1.50±0.24, mean±SE, n=22) decreased [0.46±0.24 (n=19)] after two years. In 70% of the patients, the disability did not worsen. Eleven of 18 patients showed a mild decrease of the total lesion size in magnetic resonance imaging (MRI). Conclusion MZR was well tolerated and could be used for long-term in MS as an adjunctive immunosuppressant to PSL, and the PSL doses could be decreased. A further randomized controlled trial with PSL is necessary.
(Internal Medicine 38: 636-642, 1999)