Interferon-beta therapy in multiple sclerosis - Evidence for a clinically relevant dose response

There have been considerable advances made recently in the treatment of mul tiple sclerosis (MS). In particular, interferon (IFN)beta has been demonstr ated in several independent, multicentre clinical trials to lower unequivoc ally the biological activity of this illness. The results of these trials h ave been remarkably consistent, demonstrating a reduction in both disease a ctivity and cumulative disability, using a combination of clinical and magn etic resonance imaging outcome measures. Nevertheless; the importance of th e total weekly IFN beta dose in the clinical management of individual patie nts has been controversial. However, there is considerable information available regarding the effect o f IFN beta dose on the various biochemical and clinical markers that are af fected by IFN beta, which is derived both from pre-clinical studies and mul ticentre clinical trials. On balance, convincing evidence is provided to su pport the notion that there is a clinically relevant dose-response in the u se of IFN beta to treat patients with relapsing/remitting MS. However, many of the clinical trials of IFN beta in MS have confounded the potential eff ects of dose with the possible effects of frequency of IFN beta administrat ion. As a result, it is possible that the apparent dose-response observed i n these clinical trials may be due, in part, to the more frequent dose admi nistration schedule rather than the total weekly dose.