Interferon therapy in relapsing-remitting multiple sclerosis: a systematic review and meta-analysis of the comparative trials.

BACKGROUND Early and more recent systematic reviews of placebo controlled trials disagree about the relative efficacy of the commercially available INF-ß treatments in studies of adults with RRMS. A limitation of these reviews is that they have derived their findings almost entirely from the pivotal trials and placebo controlled studies. OBJECTIVE To provide the first meta-analytic study of head-to-head and comparative trials of INF-ß agents in RRMS treatment. METHODS OVID Medline and Cochrane Library electronic databases were searched using keywords "multiple sclerosis", "interferon beta-1a", and "interferon beta-1b". Using a standardized abstraction form, three reviewers independently abstracted MRI, relapse rate, and disability (EDSS) data. RevMan5 software was used to calculate relative risk (RR) and absolute risk differences (RD) based on event rates. RESULTS High dose treatment demonstrated superior relapse reduction and MRI stability compared to low dose treatment. There was also a trend observed in the aggregate analyses of disability progression (EDSS) favoring high dose treatment. CONCLUSIONS High dose INF-ß treatment demonstrated superior relapse control and MRI stability compared to low dose treatment in a systematic review of comparative studies. These results contradict those of earlier systematic reviews and support the conclusions of more recent systematic reviews of the placebo controlled trials.