Azathioprine in multiple sclerosis--a 3 year controlled study of its effectiveness.

The results of a prospective, long-term controlled study on the treatment of multiple sclerosis with azathioprine are reported. The effect of a daily 2 mg/kg body weight dosage on 56 randomly chosen patients with multiple sclerosis is compared with a non-treated control group of 51 randomly selected multiple sclerosis patients. The azathioprine therapy was continued in all cases for more than one year, on average for 732 days. To assess the effect of therapy, the course of the disease was followed by regular examinations evaluating the severity of the disease by use of an objective weighting-scale covering the whole range of neurological signs. The individual course of the disease within the observation period was determined by means of regression analysis. On average, the disease deteriorated less rapidly for those undergoing azathioprine therapy, this being most marked for patients who had had the disease for less than two years. For those who had been affected for longer, no significant differences in the progression of the disease could be detected. The annual relapse rate was the same for both categories.