Lecanemab for Alzheimer’s Disease – What Are the Risks and Benefits in Real-World Practice?

A new treatment for Alzheimer’s disease is raising both hope and questions. Lecanemab, a monoclonal antibody targeting amyloid deposits in the brain, has been approved in several countries to slow the progression of the early stages of the disease. However, its use in real-world conditions reveals major challenges in terms of safety and efficacy.

Health authorities in the United States, Japan, the United Kingdom, and Europe have given the green light to lecanemab, but with varying recommendations. All require prior confirmation of amyloid presence in the brain before starting treatment. Special attention is given to patients carrying two copies of the ApoE ε4 gene, who are known to be at increased risk of serious adverse effects. In the United States and Japan, these patients can receive the treatment under enhanced monitoring, whereas in Europe and the United Kingdom, it is discouraged for them.

The most common side effects are related to injection and abnormalities visible on brain imaging, known as ARIA. These abnormalities can cause swelling or small hemorrhages in the brain. They occur mainly during the first infusions and affect more people carrying the ApoE ε4 gene. In most cases, these effects remain mild, but serious, even fatal, complications have been reported. Physicians must closely monitor patients, particularly through regular MRIs, and adjust treatment based on the severity of symptoms.

An analysis of pharmacovigilance data in the United States identified more than 2,600 adverse effects, 30% of which were considered serious. Headaches, chills, and confusional states are among the most common complaints. ARIA, whether associated with edema or microhemorrhages, generally appear within the first two months of treatment. Their severity varies, ranging from mild forms to cases requiring permanent discontinuation of lecanemab.

Studies conducted in specialized centers show that the treatment can stabilize cognitive symptoms in some patients, especially if started early. However, the results remain mixed. Treatment discontinuation is common, often due to side effects or a lack of noticeable improvement. The differences observed between countries are partly explained by patient inclusion criteria and follow-up protocols.

Post-marketing surveillance is essential to better understand the benefits and risks of lecanemab. Patient registries and enhanced monitoring programs help collect real-world data. This information will help refine recommendations and identify patients most likely to benefit from this treatment while minimizing risks.

The balance between efficacy and safety remains delicate. While lecanemab represents a breakthrough in the management of Alzheimer’s disease, its use must be rigorously controlled. Therapeutic decisions should be personalized, taking into account the patient’s genetic profile and overall health. The challenge is to maximize benefits while minimizing risks, pending more comprehensive data on its long-term impact.

Media Sources

Reference Document

DOI: https://doi.org/10.1007/s10072-026-08829-4

Title: Regulatory, clinical, and post-marketing challenges of lecanemab for Alzheimer’s disease: insights from real-world data

Journal: Neurological Sciences

Publisher: Springer Science and Business Media LLC

Authors: Giuseppe Marano; Roberto Da Cas; Ilaria Ippoliti; Paolo Caffarra; Nicoletta Locuratolo; Nicola Vanacore; Antonio Ancidoni