Abstract
Diminished efficacy in terms of clinical relapses and lesion load on magnetic resonance images for patients developing neutralising antibodies (NAbs) to recombinant IFN-β may be found in multiple sclerosis. NAbs become detectable over the first few years of therapy, disappearing during the treatment course in some patients and persisting longer in some others. Therefore, the administration of concomitant therapies to recombinant IFNβ to prevent the formation of NAbs could be indicated mainly in the latter group of patients at the early stage of the treatment. Among those therapies, steroids meet the best criteria in terms of either safety or impact on the development of NAbs, at the present time.