Interferon beta-1 (Avonex (TM)): clinical and MRI impacts.

This article presents critical aspects of the pivotal phase III study that led to approval of interferon beta-1a (Avonex(TM)) as treatment for relapsi ng-remitting multiple sclerosis (MS). An update on data from the pivotal st udy or other open studies, further demonstrating the practical clinical imp act of Avonex(TM), are also presented. The purpose of the pivotal study was to determine whether Avonex(TM) could slow the progressive irreversible neurological disability of relapsing-MS. 301 patients were randomised into a double-blind placebo-controlled, multic entric trial of Avonex(TM). Avonex(TM) 6.0 MUI (30 mu g) was administered b y intramuscular injection weekly. The primary outcome variable was time to sustained physical disability at 6 months progression of at least 1.0 point on the EDSS. Avonex(TM) produced a significant delay in time to sustained EDSS progression (p = 0.02). The Kaplan-Meier estimate of the proportion of patients progressing by the end of 104 weeks was 34.9 p. 100 in the placeb o group and 21.9 p. 100 in the Avonex(TM) treated group, representing a 37 p. 100 reduction in the risk of accumulating disability. Further analysis s howed that the clinical efficacy related to disability did not depend on th e definition of disability progression. Significantly fewer Avonex(TM) reci pients progressed to EDSS milestones of 4.0 or 6.0. The exacerbation freque ncy was decreased by 32 p. 100 in the Avonex(TM) group. Patients treated wi th Avonex(TM) had also a significantly lower number and volume of gadoliniu m-enhanced lesions on MRI. There was no major adverse events related to tre atment. Injection site reactions were rare and no reports of skin necrosis have been recorded. There was no significant and clinically relevant biolog ical disturbances due to Avonex(TM).