[Interferon β for multiple sclerosis. How much is good enough?]

Interferon β-1b (IFNB-1b, Betaferon®) was the first therapy for multiple sclerosis (MS) showing efficacy in a randomized controlled clinical trial. Early studies suggested a dose-dependency of the clinical efficacy of IFNB-1b. However, until recently no reliable clinical data were available to assess the potential of higher dosing to increase therapeutic efficacy. In addition, no clinical trials have been conducted to directly compare the efficacy of IFNB-1b with that of glatiramer acetate, an alternative first line treatment option for relapsing-remitting MS. Just recently, the prospective, randomized, multicenter study BEYOND was published which addressed both issues. In this review the BEYOND trial is reviewed and placed in the context of advantages and disadvantages of currently available first line therapies for MS.