What the FDA Approval of Lecanemab Means for Patients and Families: A Q&A with MBWC Clinicians

January 30, 2023

Research, Clinical Care, Q&A, ADRC News

On January 6, 2023, the U.S. Food and Drug Administration (FDA) approved lecanemab (brandname Leqembi) via the Accelerated Approval pathway to treat Alzheimer’s disease.  Our clinic team at the Memory and Brain Wellness Center would like to share some information about this newest therapy with our patients and community.

What is lecanemab? 

Lecanemab is a newly approved medication for the treatment of Alzheimer’s disease and is marketed under the brand name Leqembi. Lecanemab is administered in the form of an intravenous (IV) infusion every 2 weeks.


How does lecanemab work?

Amyloid-beta protein accumulates in the form of plaques in the brains of people with Alzheimer’s disease. This amyloid accumulation is thought to contribute to the cognitive decline seen in the disease. Lecanemab is an antibody that targets the amyloid beta deposits and allows a person’s immune system to remove the plaques from the brain. 


Is lecanemab a cure for Alzheimer’s?

No.  Though lecanemab is one of the first FDA -approved treatments to address the underlying biology of Alzheimer’s disease, it is not a cure. According to the FDA, the reduction in amyloid plaques produced by this medication is reasonably likely to lead to a slowing in the clinical decline due to the disease.

It is also important to point out that lecanemab was studied in people living with early Alzheimer’s disease and mild cognitive impairment (MCI) due to Alzheimer’s who showed evidence of a buildup of amyloid plaques in the brain. The therapy has not yet been tested on people with moderate or more advanced cases of Alzheimer’s or on individuals with other forms of dementia.


What type of diagnostic testing is required before starting this medication?

A trained physician should confirm the presence of amyloid plaques in the brain before prescribing this anti-amyloid plaque treatment. The FDA requires an amyloid protein test to demonstrate that Alzheimer’s disease is present. This can be done by collecting spinal fluid through a lumbar puncture procedure to test for amyloid or or by administering an amyloid PET brain scan. Confirmatory tests like this make sure that the patient has brain amyloid before undergoing this specialized therapy. Before considering this treatment for Alzheimer’s disease, a person must first seek care from a specialist with the expertise necessary to complete an appropriate diagnostic assessment. The University of Washington Memory and Brain Wellness Center is one of many centers with expertise in diagnosing Alzheimer’s disease.


What are potential side effects of lecanemab? 

As with any medication, lecanemab may have side effects. Because it works by helping the immune system remove amyloid deposits from the brain, some patients may experience an exaggerated immune response in the brain. If this occurs, it may cause blood vessel leakiness leading to localized brain swelling, bleeding in the brain, or both. These side effects can be seen using MRI imaging of the brain and are called amyloid-related imaging abnormalities (ARIA). In the clinical trial demonstrating benefit of lecanemab, about 13% of patients developed ARIA, though most did not have any symptoms from ARIA, and most ultimately completed the course of medication.  A few percent of patients develop a more serious degree of ARIA and cannot continue the medication. Long term effects of ARIA are not well studied.

The potential risks and benefits of lecanemab must be thoroughly considered in each person individually. Some patients with Alzheimer’s disease may not be appropriate for treatment with lecanemab, due to their doctor’s concerns about their individual balance of possible risks and benefits from treatment. Some patients are not eligible because they require blood thinners, or have other particular medical conditions which were excluded from the original studies. Additionally, before and after lecanemab is started, patients must receive special monitoring (including brain magnetic resonance imaging [MRI] scans) to screen for ARIA.


Is lecanemab available to patients now?

No, it is not available at this time. Although it has received accelerated approval from the FDA, lecanemab is not currently on formularies and not currently covered by insurance providers.   The Centers for Medicare and Medicaid (CMS) currently cover medicines like lecanemab only in the context of a clinical research trial. It is likely that CMS will reconsider lecanemab specifically in the near future, especially if the FDA grants its full approval, but these are processes that will take a number of months, and the outcome is uncertain. Our best estimate is that it may be summer 2023 at the earliest before a timeline for possible availability will become clear. Until then, we will continue to update this FAQ with current information and evidence about lecanemab.

What is the controversy about lecanemab?

Not everyone agrees that the efficacy of lecanemab is enough to justify cost, burden to patients, and risk of ARIA. The FDA has given accelerated approved this medication because its effect in removing brain amyloid makes it “reasonably likely” it is effective. In other words, we know lecanemab has a biological effect but we are not sure about its effect on memory and daily functioning.


How much will lecanemab cost patients?

The manufacturer is listing the cost of the medication itself as $26,500 per year. How the Centers for Medicare and Medicaid Services (CMS) decides to cover lecanemab will make a big difference in out-of-pocket costs, which may be less. Private insurance coverage will probably become clear only after CMS makes its determination. Other costs will include MRI scans for monitoring of ARIA, and infusion services.


What factors will influence who will be treated with lecanemab at the Memory and Brain Wellness Center?

There are two sets of factors – those defining the group of patients that are eligible for the medication and likely to benefit, and practical issues as eligible patients consider the logistics, costs, risks, and benefits of the treatment.

In general, lecanemab is indicated for patients with mild cognitive impairment due to Alzheimer’s disease, or very mild Alzheimer’s disease dementia. The medicine has not been tested for benefit or risk in asymptomatic persons, in those with moderate to severe Alzheimer’s disease, in mixed vascular and Alzheimer’s disease dementia, or in any other disease-causing memory loss and cognitive impairment.  In order to be sure of a diagnosis of Alzheimer’s disease, one must have an Alzheimer’s biomarker test on spinal fluid or by PET scan showing amyloid in the brain. Because of possible side effects on small blood vessels in the brain causing leakage of fluid (edema) or blood (microhemorrhage), patients must be able to undergo MRI scans and must not be taking blood thinners.

Factors that are important for eligible patients to consider include: 1) understanding that the effectiveness of lecanemab in general is modest, and might be hard to notice in any given; 2) understanding the risk of brain edema and microhemorrhage; 3) understanding that this is a twice monthly IV infusion that will require visits to a health care facility 4) considerations of cost.


How long do patients need to take lecanemab?

We do not yet know how long patients need to take the medication. The duration of therapy has yet to be defined, and it will require waiting for results of further studies.