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# Biogen Alzheimer’s BLA Review Extended
- URL: https://www.fdaweb.com/biogen-alzheimers-bla-review-extended/
- Published: 2021-01-29T12:00:00.000Z
- Updated: 2026-09-14T16:44:43.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5148556

FDA has extended by three months the review of a Biogen BLA for aducanumab, indicated for treating Alzheimer’s disease. The updated user fee review action target date is 6/7\. The extension was triggered by a Biogen-submitted “information request” response that included FDA-requested analyses and clinical data, which it considers a major amendment requiring additional time for review.

In November, FDA’s Peripheral and Central Nervous System Drugs Advisory Committee voted 8 to 1 that a study involving the drug did not provide strong evidence to support its effectiveness. The panel also voted 7 to 0 (4 votes uncertain) that a second study did not provide evidence of the aducanumab’s effectiveness for the treatment of Alzheimer’s. If FDA goes against the recommendations, aducanumab would be the first new Alzheimer’s drug approved in nearly 20 years.

During the meeting, panel members were not persuaded by an FDA briefing document’s discussion on effectiveness. An agency medical reviewer [said ](https://www.fda.gov/media/143502/download?ref=fdaweb.com)one of the clinical studies submitted by Biogen “provides substantial evidence of effectiveness to support approval.” Panel members also were concerned about FDA’s statistical reviewer, **Tristan Massie**, who wrote in the briefing paper that the one positive trial of aducanumab could not overcome the negative one. “There is no compelling evidence of treatment effect or disease slowing and … another study is needed to confirm or deny the positive study and the negative study,” she wrote. FDA Office of Neuroscience director **Billy Dunn** told the panel that issues with the negative trial don’t “meaningfully detract from the persuasiveness” of the positive trial. He suggested the drug might still have a clear path to approval.

Aducanumab is a monoclonal antibody licensed from Neurimmune under a collaborative development agreement. The submission is based on data from the EMERGE and ENGAGE Phase 3 multicenter, randomized, double-blind, placebo-controlled, parallel-group studies. The primary objective was reducing cognitive and functional impairment as measured by changes in the Clinical Dementia Rating-Sum of Boxes score, Biogen and Eisai say. Secondary objectives were to assess the effect of monthly doses of aducanumab as compared to placebo on clinical decline as measured by the Mini-Mental State Examination, Alzheimer’s Disease Assessment Scale-Cognitive Subscale 13 Items and Alzheimer’s Disease Cooperative Study-Activities of Daily Living Inventory Mild Cognitive Impairment Version.