On Jan. 6, 2023, the U.S. Food and Drug Administration (FDA) approved Leqembi (lecanemab-irmb) via the Accelerated Approval pathway for the treatment of Alzheimer’s disease. Leqembi is the second of a new category of medications approved for Alzheimer’s disease that target the fundamental pathophysiology of the disease.

Researchers evaluated Leqembi’s efficacy in a double-blind, placebo-controlled, parallel-group, dose-finding study of 856 patients with Alzheimerﾒs disease. The approval of Leqembi was granted to Eisai R&D.

Alzheimer’s disease is an irreversible, progressive brain disorder affecting more than 6.5 million Americans. The disease slowly destroys memory and thinking skills and eventually, the ability to carry out simple tasks. While the specific causes of Alzheimer’s are not fully known, it is characterized by changes in the brain—including the formation of amyloid beta plaques and neurofibrillary, or tau, tangles—that result in loss of neurons and their connections.

The most common side effects of Leqembi were headache, infusion-related reactions and amyloid-related imaging abnormalities (ARIA), a side effect known to occur with the class of antibodies targeting amyloid.

Leqembi should be initiated in patients with mild cognitive impairment or mild dementia stage of Alzheimer’s disease, the population in which treatment was studied in clinical trials. The labeling states that there are no safety or effectiveness data on initiating treatment at earlier or later stages of the disease than were studied.