Cedars-Sinai Blog

Ask a Doc: Lecanemab for Alzheimer’s Disease

An asian woman sitting with her older mother.

Patients with Alzheimer’s disease have limited options to treat the condition. The U.S. Food and Drug Administration (FDA) recently approved a new drug, lecanemab, that slows disease progression in people with mild cognitive impairment due to Alzheimer’s. But it could be a year or more before the medication is widely available to patients or covered by insurance.

Dr. Sarah Kremen is director of the Neurobehavior Program in the Jona Goldrich Center for Alzheimer’s and Memory Disorders and leads the Alzheimer’s Disease Clinical Trial Program at Cedars-Sinai.

Sarah A. Kremen, MD

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Here, she shares what patients should know about the new drug, which is sold under the brand name Leqembi. She also discusses other advances on the horizon and the importance of cognitive testing early in memory loss.

“Whether the new drug for Alzheimer's disease is right for people who are eligible also depends on their medical conditions."

How does lecanemab work?

Dr. Sarah Kremen: Lecanemab is the first FDA-approved medication that works to actively modify the disease by clearing amyloid proteins that form plaque in the brain. It doesn’t stop cognitive decline, but it slows it down. 

The data shows that at six months there is a statistically significant separation in cognitive function between patients who received the drug and those who received the placebo. We need more data to know what happens for people after 18 months—but it’s unrealistic to expect we’ll be giving this drug to people in perpetuity.

Who might benefit from lecanemab?

SK: This IV drug is approved for people with mild cognitive impairment or mild dementia because of Alzheimer’s. With the former, this means early-stage memory loss or thinking difficulties in people who are still doing all their usual activities independently. 

People who have mild dementia may have memory and cognitive difficulties that necessitate assistance with some responsibilities, like paying bills. In this stage, people can still actively participate in hobbies and conversations, and only close friends and family might notice changes in their thinking. 

Whether the drug is right for people who are eligible also depends on their medical conditions. It is not without potential side effects, including brain bleeds and brain swelling, and everyone will have to assess their own risk. 

There’s no right or wrong answer about taking lecanemab if someone is otherwise healthy and falls into the appropriate stage of disease. It’s going to take very thoughtful conversations between patients, their families and their care providers to decide how to proceed. 

How will patients know if they are eligible to receive this drug?

SK: We will always require some sort of biological proof of Alzheimer’s disease before we can offer patients disease-modifying therapies. Currently, we do this either with a spinal tap or with a brain scan. The brain scan isn’t widely accessible or approved by insurance. 

In the future, we’ll have blood tests for Alzheimer’s. Such tests are being studied in clinical trials to make sure they can accurately and effectively detect Alzheimer’s proteins. This will make diagnosis a lot easier and less expensive.

What other advances are being made in the treatment of Alzheimer’s disease?

SK: Exercise has a significant impact on Alzheimer’s—ongoing studies are evaluating how exercise benefits cognitive function. Some drugs in clinical trials use antibodies to mop up tau proteins, which tangle in brain cells and contribute to Alzheimer’s. Other study drugs target glucose metabolism because poorly regulated glucose levels might affect the disease.

What should someone do when they are concerned about memory loss?

SK: You should tell your primary care doctor and be persistent and proactive in requesting a cognitive assessment and labs to rule out sleep apnea, depression or vascular disease. Ask a loved one who knows you well to come to your doctor’s appointment to express their concerns about the changes they’ve noticed. 

We know that patients will want this drug, and we’ll have to turn away a lot of people whose disease is too advanced. Especially now that we are close to being able to offer treatment, Alzheimer’s screening must shift earlier so we can help more people when they are in the optimal window of time to receive this medication.