Biogen has submitted its Biologics License Application (BLA) to the Food and Drug Administration (FDA) for aducanumab as a treatment of Alzheimer disease (AD).

Aducanumab is an investigational human monoclonal antibody that targets amyloid beta; it is administered as a monthly intravenous infusion. In October 2019, Biogen announced that it would pursue approval of the investigational therapy following a consultation with the FDA regarding new data showing favorable outcomes with a higher dose of aducanumab; the Company had previously announced in March 2019 that it would discontinue the clinical program for aducanumab for early AD based on disappointing results of a futility analysis.

The BLA submission is supported by data from the phase 3 EMERGE and ENGAGE studies, as well as the phase 1b PRIME study. The multicenter, double-blind, parallel-group EMERGE study included 1638 adults aged 50 to 85 years with early AD. Patients were randomized to receive aducanumab high or low dose, or placebo. The pre-specified primary end point was the change from baseline in Clinical Dementia Rating-Sum of Boxes (CDR-SB) scores at week 78. 

Results from EMERGE showed that aducanumab high dose met the primary end point achieving a statistically significant reduction of 22% in CDR-SB scores at week 78 vs placebo (P =.01). Patients treated with high dose aducanumab also demonstrated a consistent reduction of clinical decline as measured by the Mini-Mental State Examination score (18% vs placebo; P =.05), the Alzheimer Disease Assessment Scale-Cognitive Subscale (13 Items) (27% vs placebo; P =.01) and the Alzheimer Disease Cooperative Study-Activities of Daily Living Inventory Mild Cognitive Impairment Version score (40% vs placebo; P =.001). 

Additionally, both doses of aducanumab were associated with statistically significant reductions in amyloid plaque burden vs placebo at weeks 26 and 78 (P <.001). The phase 1b PRIME study and its long-term extension also demonstrated that aducanumab reduced amyloid beta plaque in a dose- and time-dependent manner.

In the ENGAGE study, aducaumab failed to meet the primary end point for change in CDR-SB scores, however the Company noted that a subset of the data appeared to support the outcome in the EMERGE study.

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“The aducanumab BLA is the first filing for FDA approval of a treatment that addresses the clinical decline associated with this devastating condition, as well as the pathology of the disease,” said Michel Vounatsos, Chief Executive Officer at Biogen. “We are committed to driving progress for the Alzheimer disease community and look forward to the FDA’s review of our filing.”

The Company has requested Priority Review, which may shorten the FDA’s review of the application to 6 months if granted. 

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