[Prolonged treatment of multiple sclerosis with average doses of azathioprine. An evaluation of 15 years' experience].

Since 1967, 211 probable or definite multiple sclerosis (MS) patients have received azathioprine (100 mg daily) as primary immunosuppressive treatment. Treatment results are evaluated in 145 patients who have received prolonged (one year or more) continuous therapy and whose disability had been evaluated prospectively. The main characteristics of these patients are the following: male 45, female 100; mean age of onset of MS: 27 years; mean duration of treatment and follow-up: 67 and 115 months, respectively. 48 patients were in the progressive phase of MS at the onset of treatment; 17 of these had a stable disability score during therapy; however, the number of stabilized patients decreased significantly with duration of treatment. Among 97 patients in the remittent phase of the disease, 22 had no further bout during treatment, 41 had bouts but had no increase in disability, and 34 were aggravated; in 14 of these, secondary progression occurred during therapy. Haematologic, cutaneous, digestive and infectious side-effects occurred but were always reversible. In the subgroup of 131 patients who had received no other immunosuppressive treatment than azathioprine and in whom information was obtained at the end of 1982, 10 cancers (all of them epitheliomas) were diagnosed. The frequency of malignancy in the patients followed for 5 years or more was 10 p. 100. Five patients died from cancer (4 of 6 deaths in the remittent group). These results are compared with those of other series. It is suggested that the use of azathioprine in MS should be restricted.