The Food and Drug Administration (FDA)’s Peripheral and Central Nervous System Drugs Advisory Committee voted against the approval of aducanumab (Biogen) for the treatment of Alzheimer disease.

Aducanumab is an investigational human monoclonal antibody that is derived from a de-identified library of B cells collected from healthy elderly subjects with no signs of cognitive impairment or cognitively impaired elderly subjects with unusually slow cognitive decline. The investigational treatment, which is administered as a monthly intravenous infusion, binds to aggregated β-amyloid and promotes removal of amyloid from the brain.

During the meeting, the expert panel reviewed data from the phase 3 EMERGE study, which enrolled 1638 adults aged 50 to 85 years with early Alzheimer disease. Results showed that aducanumab high dose met the primary end point achieving a statistically significant reduction of 22% in Clinical Dementia Rating-Sum of Boxes (CDR-SB) scores at week 78 vs placebo (P =.01).

While the phase 3 ENGAGE study did not meet its primary end point, it was noted by the Company that a subset of the data appeared to support the outcome in the EMERGE study. Data from the phase 1b PRIME study, which showed that the effect of aducanumab on amyloid plaque was dose and time dependent, were also included in the review.

The panel was then asked to vote on several questions regarding the evidence that was presented. On the question of whether the EMERGE study, viewed independently and without regard for the ENGAGE study, provided strong enough evidence to support the effectiveness of aducanumab for the treatment of Alzheimer disease, the panel voted 1 yes, 8 no and 2 uncertain.

The panel also voted 0 yes, 7 no and 4 uncertain on whether the PRIME study provided supportive evidence on the effectiveness of aducanumab for Alzheimer disease; 5 yes, 0 no and 6 uncertain on whether there was strong evidence of a pharmacodynamic effect of aducanumab on Alzheimer disease pathophysiology; and 0 yes, 10 no, and 1 uncertain on whether it would be reasonable to consider the EMERGE study as primary evidence of effectiveness of aducanumab for Alzheimer disease, based on the totality of data from all 3 studies.

Commenting on the vote, Michel Vounatsos, Chief Executive Officer of Biogen said: “We appreciated the opportunity to share our data with the Advisory Committee, and we will continue to work with the FDA as it completes its review of our application.”

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Although not bound by the committees’ recommendations, the FDA does take them into consideration when making decisions on approval. A Prescription Drug User Fee Act target action date for the aducanumab application has been set for March 7, 2021.

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  1. Update on FDA advisory committee’s meeting on aducanumab in Alzheimer’s disease. [press release]. November 6, 2020.
  2. Combined FDA and applicant PCNS Drugs Advisory Committee Briefing document.  November 6, 2020.