Treatment of Alzheimer Disease

Symptom-oriented treatment has been the mainstay of Alzheimer disease (AD) pharmacotherapy for decades. This article reviews the evidence basis for symptomatic treatments for AD and the emerging data on amyloid-lowering therapies with possible disease-slowing effects.

Amyloid-lowering monoclonal antibody therapies entered clinical use in 2021. In July 2023, lecanemab became the first of these to gain full US Food and Drug Administration (FDA) approval and limited Medicare payment coverage. Donanemab gained similar approval status in July 2024. The approved agents remove amyloid plaque from the brain and appear to slow clinical disease progression but can produce significant adverse events known as amyloid-related imaging abnormalities with cerebral edema or effusion and with cerebral hemorrhages. Extensive safety monitoring is therefore required, including scheduled MRI scans. Also in 2023, brexpiprazole became the first agent specifically approved by the FDA for agitation associated with AD. Suvorexant, an orexin receptor antagonist, previously was approved for the treatment of insomnia in people with mild and moderate AD.

There is robust evidence for the use of acetylcholinesterase inhibitors for patients with mild, moderate, and severe dementia due to AD, including outcomes beyond changes in cognitive screening test scores. More limited studies support the use of memantine in moderate and severe stages. These agents have a primary effect of delaying decline in cognition and function and postponing the emergence of adverse behaviors. Pharmacotherapy for behavioral and psychological symptoms is less predictable, and most clinical trials have had negative results. Anti-amyloid therapies provide the first FDA-approved option to alter AD pathology, but an understanding of overall utility and value to patients remains in its infancy.