Real-world data offers a clearer picture of the safety profile for a new Alzheimer’s medication, providing patients and families with more concrete information as these treatments move from clinical trials to standard care. Researchers at Duke Health analyzed outcomes for more than 230 patients receiving lecanemab, an anti-amyloid therapy designed to remove a protein linked to the disease. The study, published in Neurology Open Access, found that treatment persistence and the incidence of side effects—specifically brain swelling or bleeding—closely matched the results seen in controlled studies.
The research tracked participants with early Alzheimer’s or mild memory impairment treated at Duke between 2023 and 2025. About 79% of the group remained on the drug for at least one year, though 21% discontinued treatment due to adverse events. One in four patients developed ARIA, or amyloid-related imaging abnormalities, which involves brain swelling or bleeding.
People with a specific high-risk Alzheimer’s gene (APOE ε4 homozygotes) were about four times more likely to develop ARIA. Rates for this group did not differ by sex. A significant minority of patients—31%—experienced serious adverse events during treatment, including infusion reactions, falls, or strokes. While some events were not necessarily directly attributable to the drug, they occurred during the course of therapy.
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Cerebral amyloid angiopathy (CAA), a condition characterized by the silent buildup of amyloid in the brain’s blood vessels, is present in over 50% of all Alzheimer’s patients and is one of the mechanisms thought to underlie ARIA. This finding highlights the urgent need for better predictive tests to identify who will develop serious side effects and determine when it is safe to resume treatment.
The study found that ARIA status was not associated with rates of change in cognitive performance at 12 months, though events could continue up to 30 weeks after starting therapy. Researchers observed two peaks in ARIA incidents around 10 weeks and 25 weeks, emphasizing the importance of continued monitoring. Seven commonly available clinical, blood, and imaging tests could not yet reliably predict who would develop ARIA, though one method involving an MRI measure of vascular changes and blood levels of the biomarker pTau/AB42 showed the most promise for identifying low-risk subjects.
Duke Health has now treated more than 400 patients with lecanemab, making it one of the most experienced centers in the country using anti-amyloid therapies. As part of its safety strategy, the team piloted an AI-supported imaging tool to help detect subtle changes on brain scans earlier and more consistently.
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The decision of whether or not these new medications are right for a patient is highly individualized. Sally Osmer, a 74-year-old patient, did not hesitate when doctors at Duke Health offered lecanemab after her diagnosis. She has a family history of the disease and began receiving infusions within a month of her diagnosis, completing more than a year on the therapy without serious side effects.
While lecanemab does not cure Alzheimer’s disease or reverse symptoms, researchers say slowing progression can help patients maintain independence longer. Osmer notes that the treatment has allowed her to remain engaged in daily life and focused on time with her family. “It’s been very uneventful in terms of side effects,” she says. “Being on lecanemab definitely gives me a sense of hope and a promise for a better future than we’ve assumed about Alzheimer’s in the past.”