Lecanemab

[2] In clinical trials, it demonstrated modest efficacy in reducing relative cognitive decline compared to placebo.

)[13] The authors concluded "Lecanemab reduced markers of amyloid in early Alzheimer’s disease and resulted in moderately less decline on measures of cognition and function than placebo at 18 months but was associated with adverse events.

[21] The efficacy of lecanemab was evaluated in a double-blind, placebo-controlled, parallel-group, dose-finding study of 856 participants with Alzheimer's disease.

[6] Efficacy of lecanemab was evaluated using the results of Study 301 (CLARITY AD), a phase III randomized, controlled clinical trial.

[6] Lecanemab is approved in the US, Japan, China, South Korea, Hong Kong, Israel, United Arab Emirates, and Great Britain.

[25] In November 2024, after re-examining its initial opinion, the CHMP recommended granting a marketing authorization to lecanemab (Leqembi) for treating mild cognitive impairment (memory and thinking problems) or mild dementia due to Alzheimer's disease (early Alzheimer's disease) in people who have only one or no copy of ApoE4, a certain form of the gene for the protein apolipoprotein E.[25][26] In August 2024, the Medicines and Healthcare products Regulatory Agency (MHRA) granted marketing authorization for England, Scotland, and Wales.

Statistically, these people develop Alzheimer's disease more frequently and earlier, but also have a particularly high incidence of ARIA when treated with lecanemab.

According to the MHRA, the risk outweighs the benefit for these people and genetic testing is recommended before starting treatment.

[33] After reviewing the clinical evidence and considering the treatments' other potential benefits, disadvantages, and contextual considerations noted above, the California Technology Assessment Forum unanimously concluded that lecanemab represents "low" long-term value of money.

[35] Lecanemab was jointly developed by the companies Eisai and Biogen and is in clinical trials for the treatment of Alzheimer's disease.

[36] It has shown statistically significant but minor effectiveness, with studies suggesting a modest decrease in cognitive decline in Alzheimer's participants compared with a control group given a placebo instead.

[37] According to a phase III clinical trial (n = 1795), lecanemab has been associated with both ARIA-E (cerebral edema) and ARIA-H (microhaemorrhages, or small haemorrhages, and hemosiderosis) sub-types.