Leqembi (lecanemab-irmb) is a prescription drug that’s prescribed for Alzheimer’s disease. Its mechanism of action is targeting and removing amyloid plaques (clumps of protein) in the brain. Experts believe that amyloid plaques contribute to the symptoms of Alzheimer’s disease. The effectiveness of this drug may vary based on your medical history and diagnosis.

Boxed warning: Risk of amyloid-related imaging abnormalities (ARIA)

Leqembi has a boxed warning about the risk of amyloid-related imaging abnormalities (ARIA). A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Leqembi can cause ARIA, which are changes visible on an MRI scan of the brain. These changes can involve swelling or bleeding in the brain, which may be life threatening or fatal in rare cases. ARIA may occur more often in people with a certain genotype (version) of a particular gene if they take Leqembi.

To learn more about this warning, talk with your doctor or pharmacist.

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The cause of Alzheimer’s disease isn’t fully understood, but it involves changes in the brain. One of these changes is the formation of plaques in the brain. These plaques are caused by a buildup of a protein called amyloid beta.

Leqembi contains the active drug lecanemab-irmb.* It’s a type of biologic drug called a monoclonal antibody. Specifically, Leqembi belongs to a drug class called amyloid beta-directed antibodies. It works by targeting amyloid beta proteins and breaking them down to reduce plaques.

Clinical trials show that Leqembi reduces amyloid beta plaques in the brains of adults with mild Alzheimer’s disease. One of these trials also notes that the drug may help slow the progression of cognitive decline by a few months.

* The letters “irmb” at the end of the drug’s name indicate that the drug is distinct from similar medications that may be created in the future.

It isn’t clear exactly how long it takes for Leqembi to work. To help determine how well Leqembi is working for you, your doctor may use imaging tests, such as a PET scan.

In the drug’s clinical trials, doctors used PET scans to measure the buildup of beta-amyloid protein in the brain. In these trials, Leqembi treatment was shown to reduce plaques in the brains of adults with mild Alzheimer’s disease. It can take several months for the drug to reach its full effect.

Your doctor may also use cognitive tests to see if your cognitive function declines while using the drug. They can provide more information on how they’ll monitor whether Leqembi is working for you.

Talk with your doctor if you have questions about what to expect with Leqembi treatment.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.