Leqembi (Lecanemab) in Early Alzheimer's Disease: A Review of ClinicalTrial Evidence and Therapeutic Implications

Lecanemab is an IgG1 monoclonal antibody that has emerged as the first FDAapproved drug to slow the progression of Alzheimer's disease by targeting amyloid plaques, with the potential to serve as a disease-modifying therapy. Ongoing clinical studies are evaluating the efficacy and safety of the medication; however, much of the current literature remains mixed regarding the clinical effectiveness of lecanemab. The results from the Clarity AD study, the largest clinical study regarding the effectiveness of lecanemab to date, revealed a statistically significant 27% reduction in the progression of cognitive decline and favorable secondary endpoints in patients with mild cognitive impairment or mild dementia, particularly in male patients as well as heterozygous APOE4 carriers. However, approximately 21% of participants who received lecanemab treatment developed amyloid-related imaging abnormalities, with a higher incidence in homozygous APOE4 carriers. These findings highlight the need to thoroughly screen patients to confirm amyloid pathology with an amyloid PET scan or CSF biomarkers, and to determine APOE4 status before treatment. Additional barriers to care include the financial cost of the medication as well as the need to administer the drug intravenously at a healthcare facility to ensure proper management. Additional studies must continue to explore the clinical impact and safety of the medication and increase its accessibility. Future research may also include analyzing the utilization of the drug in combination therapies to optimize patient outcomes. This paper aims to provide a comprehensive review of current data on lecanemab, its clinical implications, and potential future directions for the use of lecanemab.