ATTAIN study results for Plegridy (peginterferon beta-1a) in Multiple Sclerosis- Biogen

Biogen announced new data from the ATTAIN study which demonstrate the long-term safety and efficacy of Plegridy (peginterferon beta-1a) over three years in people with relapsing-remitting multiple sclerosis (RRMS). The interim results from the first year of ATTAIN, a two-year extension study of the Phase III ADVANCE study, show the benefits of continued Plegridy treatment on clinical outcomes and further define its safety profile. The study results will be presented at the 67th American Academy of Neurology's (AAN) Annual Meeting in Washington, DC. The safety and tolerability of Plegridy observed in all patients enrolled in the ATTAIN study were in line with the profile demonstrated in the ADVANCE study. The most common AEs reported were injection site reactions and flu-like symptoms, the majority of which were mild or moderate. The rate of neutralizing antibodies was one percent after three years.

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 III ADVANCE study and continue to support Plegridy's robust efficacy over time: Patients with RRMS who were administered Plegridy subcutaneously 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. 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.

Comment: Plegridy faces a crowded market of new drugs led by Tecfidera (dimethyl fumarate), also from Biogen. Its attraction is a twice a week (or four weekly) doses by subcutaneous injection and Plegridy is intended for treatment of relatively mild disease offering convenience, efficacy and fewer side effects.