Interferon-beta therapy in multiple sclerosis: evidence for a clinically relevant dose response.

Abstract

There have been considerable advances made recently in the treatment of multiple sclerosis (MS). In particular, interferon (IFN)beta has been demonstrated in several independent, multicentre clinical trials to lower unequivocally the biological activity of this illness. The results of these trials have been remarkably consistent, demonstrating a reduction in both disease activity and cumulative disability, using a combination of clinical and magnetic resonance imaging outcome measures. Nevertheless, the importance of the total weekly IFNbeta dose in the clinical management of individual patients has been controversial. However, there is considerable information available regarding the effect of IFNbeta dose on the various biochemical and clinical markers that are affected by IFNbeta, which is derived both from pre-clinical studies and multicentre clinical trials. On balance, convincing evidence is provided to support the notion that there is a clinically relevant dose-response in the use of IFNbeta to treat patients with relapsing/remitting MS. However, many of the clinical trials of IFNbeta in MS have confounded the potential effects of dose with the possible effects of frequency of IFNbeta administration. As a result, it is possible that the apparent dose-response observed in these clinical trials may be due, in part, to the more frequent dose administration schedule rather than the total weekly dose.