Background: With interferon beta-1b (IFN beta-1b), an effective therapeutic option for both relapsing-remitting and secondary progressive multiple sclerosis (RRMS and SPMS, respectively) was on trial. The effectiveness was shown by clinical parameters as well as sophisticated imaging techniques. Moreover, the effectiveness of IFN beta-1b could be directly compared to that of interferon beta-1a (IFN beta-1a) in patients suffering from RRMS in an independent trial. In long-term application, the annual number of episodes under IFN beta-1b drops by about one third compared to placebo. The difference of the detectable cerebral lesion load in the same period totaled 17.3%. For this type of MS, too, studies have shown positive results of treatment with IFN beta-1b. This applies both to clinical results and its effects on cognitive performance, quality of life and the number of cerebral lesions identifiable with MRI. The preliminary evaluation of the data at 1 year of the comparative study "Independent Comparison of Interferon = INCOMIN" shows that IFN beta-1b (on alternate days w s.c.) prevented approximately twice as many attacks as IFN beta-1a (1x/w i.m.) in patients with RRMS. In that study, therefore, IFN beta-1b, administered every 2nd day, proved more effective in the period under observation.

Conclusions: On the basis of clinical and MRI criteria, interferon beta-1b proved to be an effective treatment option in patients with RRMS or SPMS. The data show that IFN beta-1b can also be employed in the early stages of MS. The comparative study underscores the importance of frequent doses of interferon in the treatment of MS.