Lecanemab: A Well-Tolerated Treatment for Early-Stage Alzheimer's Disease in Real-World Settings

The recent approval of lecanemab by the Food and Drug Administration in 2023 marked a significant milestone in Alzheimer's disease treatment. This innovative antibody therapy has demonstrated a capacity to modestly slow the progression of Alzheimer's during clinical trials, offering hope to many patients. However, concerns about side effects such as brain swelling and bleeding—known as amyloid-related imaging abnormalities (ARIA)—have caused hesitation among patients and healthcare providers.

To better understand the safety profile of lecanemab outside controlled trial environments, researchers at Washington University School of Medicine in St. Louis conducted a retrospective study involving 234 patients with very mild or mild Alzheimer's disease receiving treatment at the university's Memory Diagnostic Center. The findings revealed that severe adverse events were rare, with only about 1% of patients experiencing serious side effects requiring hospitalization. Notably, patients with the earliest signs of Alzheimer's, who typically have the mildest symptoms, showed the lowest risk for complications.

The study emphasizes that lecanemab effectively clears amyloid plaques—protein deposits associated with Alzheimer's—thus potentially extending independent living by approximately 10 months. The safety results align with those from previous clinical trials, where most cases of ARIA were asymptomatic and detected only through sensitive brain imaging. Only a small percentage of patients, around 2.8%, experienced mild symptoms such as headaches, confusion, or dizziness, which generally resolved within months.

This real-world evidence suggests that with proper monitoring and infrastructure, lecanemab can be safely administered in outpatient settings. It also highlights the importance of early treatment, as patients with very mild Alzheimer's derive the greatest benefit and face the least risk. The study's authors advocate for increased awareness and confidence among clinicians and patients to prevent delays in treatment stemming from fears of side effects.

Lecanemab works by targeting amyloid plaques in the brain, a hallmark of disease pathology, and its use is recommended for individuals in the early stages of Alzheimer's with mild or very mild symptoms. The treatment involves infusions every two weeks, with continuous monitoring through advanced brain imaging techniques to detect any adverse effects early. When ARIA symptoms occur, the drug is discontinued, and in some cases, patients are treated with steroids to mitigate complications.

Overall, the research demonstrates that most patients tolerate lecanemab well outside the confines of clinical trials, reinforcing its potential as a cornerstone therapy for early Alzheimer's disease. These insights may help shape future treatment guidelines and improve patient outcomes.