Lymphocytotoxic nucleoside analog cladribine (2-chlorodeoxyadenosine) has recently been reported to favourably alter the clinical course of chronic progressive multiple sclerosis (MS). In the present study 10 patients with the remitting-relapsing form of MS were treated with six courses of this drug (5 mg subcutaneously or 10 mg orally, once daily, repeated on five consecutive days) given once a month, followed by two additional courses at three month intervals. The patients were observed for two years after the initiation of the therapy. The treatment resulted in the reduction of lymphocyte counts to approx. 40% of the initial value at 6 months, with a trend toward recovery evident only at 24 months. Neurological status of the patients (expressed semiquantitatively according to the EDSS scale) showed a significant improvement between 6 and 15 month of the study. The number of relapses, compared to the two-year period immediately before the treatment, remained unchanged in three patients, and was markedly reduced (almost five times on average) in the remaining seven patients. Patients who experienced the reduced relapse rate also seemed to show longer and more pronounced improvement in their neurological status.

Keywords: Multiple Sclerosis, cladribine, Immunosuppression