Interferon β-1b: latest published results, 1995

Interferon β-1b (Betaseron) has been shown in a randomized, double-blind, placebo-controlled study to reduce relapse rate, relapse severity and MRI progression in patients with relapsing-remitting MS. The recently published Betaseron extension trial and studies from the National Institutes of Health provide additional evidence suggesting an important treatment effect The major new findings from these studies are reviewed in this paper. Other findings from these recent studies merit attention, however. Specifically, neutralizing antibody formation was seen in 38% of patients receiving high-dose Betaseron at 3 years. With the development of these antibodies, there was no longer clinical evidence that the drug remained effective. This observation must be considered carefully when initiating Betaseron therapy. The Betaseron trial suggests that MRI is an imperfect predictor of clinical disease activity. Of particular interest was the finding that patients receiving low-dose Betaseron developed ‘confirmed treatment failure’ sooner than placebo-treated patients, despite a clear treatment benefit on MRI-detected evidence of subclinical disease activity.