Biogen announced results from the ATTAIN study which is investigating the long-term safety and efficacy of Plegridy (peginterferon beta-1a) over three years in patients with relapsing-remitting multiple sclerosis (RRMS). The study results will be presented at the 67th American Academy of Neurology’s (AAN) Annual Meeting in Washington, D.C.

ATTAIN is a two-year extension study of the Phase 3 ADVANCE study. Interim results from the first year of ATTAIN, show benefits with continued Plegridy treatment on clinical outcomes. The efficacy data from the first year of the ATTAIN study represent patients who have three years of continuous, fixed-dose treatment with Plegridy. The efficacy findings are consistent with the Phase 3 ADVANCE study and continue to support Plegridy’s efficacy over time.

Patients with RRMS given Plegridy every two weeks over the three year period maintained positive efficacy results on clinical outcomes including annualized relapse rate (ARR), the proportion of patients suffering a relapse, and the proportion of patients with 24-week confirmed disability progression. Plegridy also showed continued efficacy over the three-year period across important MRI measures: number of gadolinium (Gd+) enhanced lesions, new T1-hypointense lesions, and new or newly enlarging T2-hyperintense lesions.

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Additionally, the results from the study included a post-hoc analysis on NEDA outcomes, which in ATTAIN were defined as no evidence of disease activity on clinical and MRI measures, indicating no relapses and no onset of 24-week disability progression, no Gd+ lesions, and no new or enlarging T2-hyperintense lesions. The percentage of patients in the intent-to-treat (ITT) population who achieved NEDA were 34.8% in year one and 54.3% in year two of the ADVANCE study, and 48.7% in year one of the ATTAIN study, demonstrating continued efficacy over a period of three years.

Plegridy is already indicated for relapsing forms of multiple sclerosis (MS).

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