Lecanemab-irmb (Leqembi – Eisai/Biogen), the IV amyloid-directed monoclonal antibody that received accelerated approval from the FDA in January 2023 for treatment of early Alzheimer's disease, has now received full approval from the FDA based on a trial showing that it slowed cognitive and functional decline in patients with mild cognitive impairment (MCI) or mild Alzheimer's disease dementia and confirmed presence of brain amyloid. The IV amyloid-directed monoclonal antibody aducanumab (Aduhelm) has received only an accelerated FDA-approval for the same indication.

Lecanemab-irmb (Leqembi – Biogen/Eisai), an IV amyloid beta-directed monoclonal antibody, has received accelerated approval from the FDA for treatment of Alzheimer's disease. The label states that treatment with Leqembi should be initiated in patients with mild cognitive impairment (MCI) or mild dementia, the population in which the drug was initiated in clinical trials. Lecanemab is the second IV amyloid-beta directed monoclonal antibody to be approved for this indication; aducanumab (Aduhelm) was approved in 2021 and has the same restrictions on treatment initiation.

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

View the Comparison Table: Drugs for Alzheimer's Disease

A once-weekly transdermal formulation of the acetylcholinesterase inhibitor donepezil (Adlarity – Corium) has been approved by the FDA for treatment of mild, moderate, and severe Alzheimer's disease (AD) dementia. Donepezil is the second acetylcholinesterase inhibitor to become available in a transdermal formulation; transdermal rivastigmine (Exelon Patch), which is applied once daily, has been available for years for the same indication. Donepezil is also available in oral formulations (Aricept, and generics) for treatment of AD dementia.

In June 2021, the FDA approved the IV amyloid beta-directed monoclonal antibody aducanumab (Aduhelm) for treatment of Alzheimer’s disease. The approval did not restrict use of the drug to patients with mild cognitive impairment or mild dementia, which was the population enrolled in the clinical trials. Now, Biogen, with the permission of the FDA, has made an addition to the labeling of the drug that says: Treatment with Aduhelm should be initiated in patients with mild cognitive impairment or mild dementia stage of disease, the population in which treatment was initiated in clinical trials. There are no safety or effectiveness data on initiating treatment at earlier or later stages of the disease than were studied.

Aducanumab-avwa (Aduhelm – Biogen/Eisai), an IV amyloid beta-directed monoclonal antibody, has received accelerated approval from the FDA for treatment of Alzheimer's disease. The approval was based on the surrogate endpoint of reduction in amyloid beta plaques in the brain. The manufacturer is required to conduct an additional randomized controlled trial to establish that reducing amyloid beta plaques with aducanumab improves clinical outcomes in patients with Alzheimer's disease.