In January 2023, the U.S. Food and Drug Administration (FDA) granted accelerated approval to lecanemab, an Alzheimer’s drug sold under the brand name Leqembi. It’s one of the first treatments designed to target a process believed to drive the disease, rather than only easing symptoms. Here’s what patients and families should know about how it works, who it’s for, and its risks.
How Leqembi works
People with Alzheimer’s disease build up sticky clumps of a protein called amyloid beta in the brain. These clumps, called plaques, are one of the hallmarks of the disease. Leqembi is an antibody that attaches to amyloid and helps the body clear it. It’s given as an intravenous (IV) infusion every two weeks.
Leqembi was developed by the Japanese drugmaker Eisai in partnership with Biogen. It followed Aduhelm, an earlier amyloid-targeting drug from the same partnership whose 2021 approval was highly controversial because of mixed evidence that it helped patients.
What the evidence shows
The FDA’s accelerated approval was based on a mid-stage trial showing that Leqembi significantly reduced amyloid plaque on brain scans. Accelerated approval allows a drug to reach patients based on a marker that is “reasonably likely” to predict benefit, with the requirement that the company confirm the benefit in further studies.
Unlike Aduhelm, Leqembi already had results from a larger Phase 3 confirmatory trial. In that 18-month study, people taking Leqembi had about 27% slower decline on a standard measure of memory and thinking compared with those taking a placebo. That’s a modest effect. It doesn’t stop or reverse the disease, but it may help people keep their abilities somewhat longer. Leqembi later received traditional (full) FDA approval in July 2023 based on those results.
Who it’s for
Leqembi is approved for people with early Alzheimer’s disease, meaning mild cognitive impairment or mild dementia caused by Alzheimer’s. It isn’t intended for people with moderate or advanced disease. Before starting treatment, doctors must confirm that amyloid is present in the brain, usually with a PET scan or a spinal fluid test.
Safety concerns
The most important risk is a side effect called ARIA (amyloid-related imaging abnormalities), which can involve swelling or small bleeds in the brain. Many cases cause no symptoms and are found on routine MRI scans, but some can be serious. Deaths involving brain bleeding were reported in some trial participants, including people taking blood thinners. Because of this, patients get regular MRI monitoring, and the drug’s label urges caution in people taking blood-thinning medicines. People who carry two copies of a gene called APOE4 have a higher risk of ARIA, so genetic testing is often discussed before treatment.
Cost and coverage
Eisai set the list price at $26,500 a year, not counting the cost of infusions, scans and monitoring. Independent analysts at the Institute for Clinical and Economic Review (ICER) questioned whether that price matched the drug’s benefit. At first, Medicare covered amyloid-targeting drugs only for people in clinical trials. After full approval, Medicare broadened coverage for eligible patients whose doctors take part in a data registry.
What this means for you
- Don’t ignore memory changes. Leqembi only helps in the early stages, so getting evaluated early matters.
- Ask a specialist. A neurologist or memory clinic can confirm a diagnosis and tell you whether you’re a candidate.
- Weigh benefits and risks. Discuss the modest benefit, the time commitment of infusions, monitoring requirements and the risk of brain swelling or bleeding.
- Review your medications. Tell your doctor if you take blood thinners.
- Keep up healthy habits. Physical activity, managing blood pressure and staying socially engaged support brain health at every stage.
The bottom line
Leqembi is a meaningful step in Alzheimer’s treatment: it clears amyloid and modestly slows decline in early disease. It isn’t a cure, and it carries real risks, so it’s a decision best made with a specialist who knows your health history.
This article is for general information and isn’t medical advice. Talk with your healthcare provider about your individual needs.
