L. DurelliA. OggeroE. VerdunP. BarberoA. PipieriG. IsoardoA. Ricci M. ClericoG. BradacB. BergamascoM. Bergui

Interferon beta (IFN-β) reduces exacerbation rates in patients with relapsing-remitting multiple sclerosis (MS), but some patients do not respond to treatment. Recent stud- ies have shown a clear dose-response effect on the reduction of exacerbation rates, and on burden of disease accumulation and active lesion frequency seen on MRI. During treatment with 8 MIU IFN-β we noticed a 30% rate of treatment fail- ure. We then treated non-responders with 12 MIU IFN-β and observed significant improvement in the clinical signs of dis- ease activity. In order to compare the efficacy of two differ- ent doses of IFN-β-1b, a multicenter study for the optimiza- tion of interferon for MS (OPTIMS) has been organized. The design of the study is presented here.