Multicentre double-blind study of effect of intrathecally administered natural human fibroblast interferon on exacerbations of multiple sclerosis.

In this randomised, double-blind, placebo-controlled, 2-year multicentre study intrathecally administered natural human fibroblast interferon (IFN-B) was effective in reducing exacerbations of multiple sclerosis (MS) in patients with exacerbating/remitting disease. The mean reduction in exacerbation rate of 34 patients who received IFN-B (recipients) was significantly greater during the study than that of 35 patients who received placebo (p less than 0.04). The prestudy exacerbation rates were comparable in recipients and controls, but the rate at the end of the study was significantly lower in recipients than in controls (p less than 0.001). IFN-B was given by nine or ten lumbar punctures over the first 6 months of the study, and patient observations continued for 2 years. IFN-B was well tolerated in 95% of the recipients, and the side-effects experienced were clearly acceptable for the benefits achieved. Low doses of indomethacin reduced the toxicity of IFN-B and played an important role in successful double-blinding.