What to consider about prescriptions of Lecanemab for early Alzheimer’s

The benefits of lecanemab for early Alzheimer's disease are modest and the potential adverse events serious, according to an article published in the Canadian Medical Association Journal (CMAJ).The article, “Lecanemab use for early Alzheimer disease in Canada,” provides an overview of the medication, recently approved by Health Canada to treat early Alzheimer disease. It advises healthcare professionals to discuss the risks and benefits with patients and their caregivers and to make a shared decision.“Clinical benefits are modest at best, with uncertain impacts on quality of life, independence and caregiver burden,” Dr. Sharon Straus, a geriatrician at Unity Health Toronto and a professor at the University of Toronto, wrote with coauthors. “The interpretation of benefits from lecanemab may be influenced by the limited availability of therapies for and the personal and societal burdens of Alzheimer disease.”Lecanemab is a treatment that uses a lab-made antibody to target and help clear amyloid-beta, a protein that can build up in the brains of people with Alzheimer’s. By helping remove this protein, the drug may slow the disease process.This approach is based on the amyloid hypothesis, the idea that amyloid buildup plays an important role in Alzheimer’s disease. However, this theory remains debated.Lecanemab is only used for people in the early stages of Alzheimer’s disease, specifically those with mild cognitive impairment or mild dementia caused by Alzheimer’s. It was approved for use in Canada as of January 2026. But, Canada’s Drug Agency and Quebec’s Institut national d’excellence en santé et en services sociaux have recommended that it not be publicly funded. It costs about $35,000 to $40,000 per year per patient, and most provinces and territories remain uncertain about whether they will cover it.The trial resultsLecanemab was approved mainly because of results from a phase 3 clinical trial called Clarity AD. The trial included 1,795 people who had mild cognitive impairment or mild dementia due to Alzheimer’s. All participants also had evidence of amyloid in the brain, confirmed through either a spinal fluid test or a PET scan.Participants received either lecanemab by IV every two weeks or a placebo for 18 months. Researchers measured the drug’s effect using the Clinical Dementia Rating–Sum of Boxes (CDR-SB). This scale looks at both memory and thinking problems and how well a person is functioning in daily life.Lecanemab slowed worsening on the CDR-SB scale more than those taking placebo. The difference was 0.45 points on the CDR-SB scale, which was described as a 27% relative reduction in decline. But this was not at the level usually considered meaningful for patients on this scale, which is about one point. This suggests the measured benefit may be too small to make a noticeable difference in day-to-day life.Safety concernsTo be eligible for treatment, patients must meet specific medical criteria, including clinical assessment, lab tests and brain imaging, the article notes.The main safety concern with lecanemab is amyloid-related imaging abnormalities, or ARIA, which can happen when the treatment helps move amyloid protein out of blood vessels in the brain. These changes are usually found on MRI scans. ARIA can appear as swelling or fluid in the brain, called ARIA-E, or as tiny areas of bleeding in the brain, called ARIA-H.In the Clarity AD trial, ARIA occurred in 21.5% of patients taking lecanemab, compared with 9.5% of those taking placebo. Most cases did not cause symptoms. Among patients taking lecanemab who developed ARIA, about 85% had no symptoms and were identified through routine MRI monitoring. When symptoms did occur, they affected about 3% of patients. Symptoms could include headache, confusion, vision changes, dizziness or seizures.Serious ARIA events, including bleeding in the brain, occurred in about 0.7% of patients taking lecanemab. Bleeding complications were more common in patients who were also taking blood thinners.Because of this risk, lecanemab can make treatment decisions more complicated for patients who need blood thinners or clot-busting medications.The authors recommend shared decision-making and provide a tool to help clinicians engage with patients and caregivers.“Given the uncertain clinical benefit, risks of adverse events, and resource and financial implications, the decision to initiate lecanemab should be individualized,” the authors wrote.“Some patients who place a high value on small potential delays in disease progression may choose to proceed and accept the risks, monitoring requirements, and out-of-pocket costs. In some cases, deferring treatment pending further evidence may be a reasonable approach,” the authors concluded.

What to consider about prescriptions of Lecanemab for early Alzheimer’s

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