Last reviewed: 20 Sep 2021
Last updated: 21 Jul 2021
21 Jul 2021

FDA approves aducanumab for Alzheimer disease

Aducanumab, an antibody directed against amyloid beta, has been approved by the Food and Drug Administration (FDA) for the treatment of Alzheimer disease (AD).

Patients with mild AD receiving aducanumab showed a significant dose- and time-dependent reduction of amyloid beta plaque in phase 3 trials; patients in the control arm showed no reduction.[191][192] While a reduction of amyloid beta plaque in the brain, a surrogate endpoint, is reasonably likely to predict a reduction in cognitive decline, the FDA notes that there are residual uncertainties regarding the clinical benefit of aducanumab. The accelerated approval necessitates that post-approval studies are conducted; continued approval is contingent upon verification of clinical benefit in these trials.

Treatment should be initiated only in patients with mild cognitive impairment or mild dementia stage of disease, to reflect the population in the clinical trials. There are no safety or effectiveness data on initiating treatment at earlier or later stages of Alzheimer disease.

See Management: emerging

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History and exam

Key diagnostic factors

  • memory loss
  • disorientation
  • nominal dysphasia
  • misplacing items/getting lost
  • apathy
  • decline in activities of daily living and instrumental activities of daily living (IADLs)
  • personality change
  • unremarkable initial physical exam

Other diagnostic factors

  • mood changes
  • poor abstract thinking
  • constructional dyspraxia
  • prosopagnosia
  • autoprosopagnosia

Risk factors

  • advanced age
  • family history
  • genetics
  • Down syndrome
  • cerebrovascular disease
  • lifestyle factors and medications
  • less than high school education
  • traumatic brain injury
  • depression
  • hearing loss
  • hyperlipidemia
  • female sex
  • elevated plasma homocysteine level
  • artificially sweetened soft drink consumption

Diagnostic investigations

1st investigations to order

  • bedside cognitive testing
  • CBC
  • metabolic panel
  • serum thyroid-stimulating hormone (TSH)
  • serum vitamin B12
  • urine drug screen
  • CT
  • MRI

Investigations to consider

  • cerebrospinal fluid (CSF) analysis
  • serum rapid plasma reagin/Venereal Disease Research Laboratory (VDRL)
  • serum HIV
  • formal neuropsychological testing
  • genetic testing
  • fluorodeoxyglucose-PET (FDG-PET)
  • single-photon emission CT (SPECT)
  • electroencephalogram (EEG)

Treatment algorithm



Judith Neugroschl, MD

Associate Professor of Psychiatry

Icahn School of Medicine at Mount Sinai

New York



JN declares that she has no competing interests.


Dr Judith Neugroschl would like to gratefully acknowledge Dr Brandy R. Matthews, Dr Asif S. Bhutto, and Dr Julie K. Gammack, the previous contributors to this topic.


BRM, ASB, and JKG declare that they have no competing interests.

Peer reviewers

Roy J. Goldberg, MD, FACP, AGSF, CMD

Medical Director

Kings Harbor Multicare Center

New York



RJG declares that he has no competing interests.

Philip Scheltens, MD, PhD

Professor of Neurology

Department of Neurology/Alzheimer Center

VU University Medical Center


The Netherlands


PS declares that he has no competing interests.

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