Data presented today show that TECFIDERA ® (dimethyl fumarate) continues to offer consistent and strong efficacy combined with a favorable safety profile in a broad range of patients with relapsing-remitting multiple sclerosis (RRMS), including those patients who are newly diagnosed with the disease. These data were presented by Biogen Idec (NASDAQ: BIIB) at the 29 th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) in Copenhagen, Denmark from 2-5 October. Interim analyses from the ENDORSE long-term extension study show that TECFIDERA maintained its effect in reducing disease activity in patients treated for four years. No new or worsening safety signals were observed in patients who had received TECFIDERA for up to six and a half years. In addition, a separate post-hoc analysis of the Phase 3 DEFINE and CONFIRM clinical trials shows that TECFIDERA significantly reduced multiple sclerosis (MS) relapses in treatment-naïve patients, while delaying the overall progression of the disease over time. “Because MS is a chronic, life-long disease, physicians and patients need to know they are taking a treatment that will offer them sustained efficacy over the long-term with a consistent safety profile,” said Doug Williams, executive vice president, Research and Development, Biogen Idec. “These analyses provide important information on the benefits of TECFIDERA’s strong efficacy and favorable safety for a wide range of patients with RRMS – from those treating their MS for the first time to those who have been on TECFIDERA treatment for up to six and a half years.” ENDORSE Interim Clinical Efficacy and MRI OutcomesENDORSE is a global, dose-blind extension study to determine the long-term safety and efficacy of TECFIDERA (240 mg, dosed twice a day (BID) or three times a day (TID)). Patients who received two years of TECFIDERA in DEFINE and CONFIRM continued on the same dose in ENDORSE. Patients who previously received placebo or glatiramer acetate (GA; 20 mg subcutaneous daily injection; CONFIRM only) in DEFINE or CONFIRM were randomized 1:1 to TECFIDERA BID or TID. All currently enrolled patients included in the interim analyses had completed four years in the TECFIDERA clinical program (two years in DEFINE or CONFIRM plus two years in ENDORSE). At present, some patients have received TECFIDERA treatment for up to six and a half years. Interim efficacy results found that patients who continued on TECFIDERA treatment in ENDORSE for two years experienced sustained clinical efficacy (as measured by relapse and disability progression endpoints), similar to what was observed after two years in DEFINE and CONFIRM. These patients also experienced a similarly low frequency of MRI lesions over four years (as measured by new or enlarging T2-hyperintense lesions; new non-enhancing T1-hypointense lesions; and gadolinium-enhanced (Gd+) lesions).