A new Washington University School of Medicine in St. Louis study discovered that the Alzheimer’s disease FDA-approved drug lecanemab is well tolerated in patients outside of trials. The study reveals real-world experience in different settings with fewer side effects and confirms the drug slows cognitive decline. Patients who took the drug had tolerable reactions, primarily infusion-related reactions, and the results support broader clinical use.
The Food and Drug Administration‘s approval of lecanemab, a new Alzheimer’s medication shown in clinical trials to reduce the disease slowly over time, in 2023 was greeted by some in the field as the first drug of its kind to be able to impact the disease. Side effects, such as brain swelling and bleeding, in clinical trials have cautioned some patients and physicians away from the treatment.
Once medications are launched into the real world with wider demographics, their effects may alter slightly. In their investigation on the side effects of lecanemab therapy in their clinic patients, researchers at Washington University School of Medicine in St. Louis discovered that serious side effects were uncommon and controllable.
Researchers discovered that just 1% of patients had serious adverse effects that necessitated hospitalization, which aligns with the findings of meticulously monitored clinical studies. The researchers discovered that patients with relatively mild symptoms in the early stages of Alzheimer’s disease had the lowest chance of complications. This information can help patients and clinicians navigate conversations about the risks of the medication.
This new class of medications for early symptomatic Alzheimer’s is the only approved treatment that influences disease progression,
But fear surrounding the drug’s potential side effects can lead to treatment delays. Our study shows that WashU Medicine’s outpatient clinic has the infrastructure and expertise to safely administer and care for patients on lecanemab, including the few who may experience severe side effects, leading the way for more clinics to safely administer the drug to patients.
Barbara Joy Snider
Lecanemab, marketed as Leqembi, is a monoclonal antibody designed to treat Alzheimer’s disease by targeting amyloid beta plaques in the brain, which are associated with the progression of the disease. Developed by Eisai, Biogen, and BioArctic, it was granted accelerated approval by the FDA in January 2023, followed by full approval in July 2023. Clinical trials have demonstrated its ability to slow cognitive and functional decline by 27% over 18 months in individuals with mild cognitive impairment or mild dementia. The medication is administered via intravenous infusion at a dose of 10 mg/kg, typically over a one-hour session. However, common side effects include headache, infusion-related reactions, and amyloid-related imaging abnormalities (ARIA), which can lead to brain swelling or bleeding in some cases. The European Medicines Agency (EMA) issued a positive opinion in November 2024, paving the way for broader international approvals. Its availability in South Korea (May 2024) and Mexico (December 2024) highlights growing global acceptance of this novel treatment.
Lecanemab hesitancy is caused by a side effect called amyloid-related imaging abnormalities, or ARIA. Brain scans reveal the abnormalities, which usually only impact a relatively tiny part of the brain and show signs of hemorrhage or swelling. 12.6% of participants in lecanemab clinical trials had ARIA; the majority of these cases were asymptomatic and resolved on their own. About 2.8% of participants who received treatment reported having symptoms such as headaches, nausea, dizziness, and confusion. Occasional deaths have been attributed to lecanemab in an estimated 0.2% of people treated.
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