January 6, 2023 – Today, as expected, the US Food and Drug Administration granted accelerated approval to lecanemab, a monoclonal antibody against the beta amyloid protein that accumulates in the brain of people with Alzheimer’s disease. Lecanemab was approved on the basis of the treatment’s demonstrated effect of lowering levels of brain amyloid, as measured by a type of brain scan known as positron emission tomography (PET) imaging. 
Lecanemab is now approved for the treatment of patients with mild cognitive impairment or mild dementia, and should be used in patients in whom that same amyloid PET brain scan (or measures of amyloid in the cerebrospinal fluid) suggests that Alzheimer’s disease is the most probable cause of the person’s cognitive impairment.
The treatment is not approved for people with moderate or severe dementia, or as a prevention for cognitive impairment. Lecanemab joins the drug aducanumab as the second treatment that directly targets the biology of Alzheimer’s disease to receive accelerated approval. Neither drug has received full approval, which relies on demonstration of clinical benefit, rather than solely demonstration of biological effect. Lecanemab, which will also be known by the brand name Leqembi, remains under consideration for full approval by the FDA. More is anticipated in the coming months on how the FDA will approach this decision. The results of a Phase 3 clinical trial of lecanemab were viewed by many in the field to be compelling (https://mind.uci.edu/dare-we-say-consensus-achieved-lecanemab-slows-the-disease/), though debate about the meaningfulness of lecanemab’s clinical benefit will be a central feature of discussion, now that it is approved and as a full approval decision looms (https://www.washingtonpost.com/health/2023/01/06/alzheimers-drug-lecanemab-fda-approval/). As always, stay tuned to the UCI MIND blog for the latest on these and other issues related to Alzheimer’s disease and related dementia research progress.
