Lecanemab

Pronunciation: leh-kan-e-mab
Generic name: lecanemab-irmb
Brand name: Leqembi
Dosage form: injection for intravenous use
Drug class: Miscellaneous central nervous system agents

Medically reviewed by Carmen Pope, BPharm. Last updated on Nov 4, 2024.

What is lecanemab?

Lecanemab (brand name Leqembi) is used to slow disease progression of Alzheimer’s disease (AD) in people with mild cognitive impairment or mild dementia.

• Your healthcare provider will make sure you have amyloid beta plaques before starting treatment with lecanemab.
• The full biological name of lecanemab is lecanemab-irmb.

Lecanemab's mechanism of action involves targeting and removing beta-amyloid plaques in the brain. Beta-amyloid is a protein that abnormally buildups in the brains of people with AD and is thought to contribute to the progression of the disease. Lecanemab helps control AD but does not cure it (see What is the mechanism of action for Leqembi?).

Lecanemab is not a cure for AD but can slow cognitive decline by approximately 27% over 18 months in most people with AD (see How effective is Leqembi in delaying Alzheimer's disease?). Lecanemab belongs to the drug class called monoclonal antibodies. Another monoclonal antibody used for AD is Kinsunla (see Leqembi Vs Kinsula).

Lecanemab first gained FDA approval under the accelerated approval pathway on January 6, 2023. This was extended to full approval on July 06, 2023. There is no lecanemab generic.

Lecanemab side effects

The most common side effects of lecanemab are:

• infusion-related reactions, which can be serious
• headache
• swelling in areas of the brain, with or without small bleeding spots in or on the brain's surface (ARIA).

Serious side effects and warnings

Lecanemab may cause serious side effects and one lecanemab controversy relates to the risk of brain swelling and bleeding. Lecanemab carries a Boxed Warning for Amyloid-related imaging abnormalities.

Amyloid Related Imaging Abnormalities or “ARIA”. Lecanemab can cause a condition called ARIA which does not usually cause any symptoms but serious symptoms can occur. ARIA is most commonly seen as temporary swelling in areas of the brain that usually resolves over time. Some people may also have small spots of bleeding in or on the surface of the brain, and infrequently, larger areas of bleeding in the brain can occur. Most people with this type of swelling in the brain do not get symptoms, however, some people may have symptoms, such as headache, confusion, dizziness, vision changes, nausea, difficulty walking, or seizures.

Some people have a genetic risk factor (homozygous apolipoprotein E gene carriers) that may cause an increased risk for ARIA. Talk to your healthcare provider about testing to see if you have this risk factor.

Some medicines can increase the risk for larger areas of bleeding in the brain in patients taking lecanemab. Talk to your healthcare provider to see if you are on any medicines that increase this risk.

Your healthcare provider will do magnetic resonance imaging (MRI) scans before and during your treatment with lecanemab to check you for ARIA. Call your healthcare provider or go to the nearest hospital emergency room right away if you have any of the symptoms listed above.

Serious allergic reactions. Swelling of the face, lips, mouth, or tongue, hives, or difficulty breathing has happened during a lecanemab infusion. Tell your healthcare provider if you have any symptoms of a serious allergic reaction during or after your infusion.

Infusion-related reactions. Infusion-related reactions are a common side effect that can be serious. Tell
your healthcare provider right away if you get these symptoms during an infusion of lecanemab:

• fever
• flu-like symptoms (chills, body aches, feeling shaky, and joint pain)
• nausea
• vomiting
• dizziness or lightheadedness
• changes in your heart rate or feel like your chest is pounding
• difficulty breathing or shortness of breath.

If you have an infusion-related reaction, your healthcare provider may give you medicines before your lecanemab infusions to decrease your chance of having an infusion-related reaction. These medicines may include antihistamines, anti-inflammatories, or steroids.

These are not all the possible side effects of lecanemab. For more information, ask your healthcare provider or pharmacist, or click on the link below for more detailed information on side effects. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Lecanemab cost

The cost of lecanemab depends on your insurance coverage and Leqembi Copay eligibility. See the Eisai Patient Support for assistance with insurance coverage and identifying financial support programs. Medicare covers 80% of the cost of lecanemab but there are other costs, such as PET scans and follow-up MRI scans that may not be covered. See Leqembi Prices, Coupons, Copay Cards, and Patient Assistance for more information.

Leqembi Companion is a website designed to help support you throughout your treatment with helpful tips and useful information about your lecanemab infusion.

Before receiving lecanemab

Do not receive lecanemab if you are allergic to lecanemab, Leqembi, or any of the inactive ingredients in the lecanemab injection (see below for a list of inactive ingredients).

Tell your healthcare provider about all of your medical conditions, including if you:

• are pregnant or intending to become pregnant
• are breastfeeding or intending to breastfeed.

Pregnancy

It is not known if lecanemab will harm your unborn baby. Tell your healthcare provider if you become pregnant during lecanemab treatment.

Breastfeeding

It is not known if lecanemab passes into breast milk. Talk to your healthcare provider about the best way to feed your baby while receiving this medicine.

How do I receive lecanemab?

Lecanemab is given by a healthcare provider via a needle placed into a vein (this is called an intravenous [IV] infusion) in your arm.

• Lecanemab is given every 2 weeks.
• Each lecanemab infusion will last about 1 hour.

You may receive medications before your infusion, such as antihistamines, anti-inflammatories, or steroids, to reduce your risk of having an infusion-related reaction with lecanemab. Tell your healthcare provider right away if you get these symptoms during an infusion of lecanemab:

• fever
• flu-like symptoms (chills, body aches, feeling shaky, and joint pain)
• nausea
• vomiting
• dizziness or lightheadedness
• changes in your heart rate or feel like your chest is pounding
• difficulty breathing or shortness of breath.

Lecanemab dosing

Usual Lecanemab Adult Dose for Alzheimer’s Disease:

• The recommended lecanemab dosage is 10 mg/kg.
• The lecanemab injection is diluted and then administered as an intravenous infusion over approximately one hour, once every two weeks.

Related/similar drugs

donepezil, memantine, Aricept, Namenda, rivastigmine, Exelon

What other drugs will affect lecanemab?

Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

Especially tell your healthcare provider if you take medicines to reduce blood clots from forming (such as antithrombotic or blood-thinning medicines, including aspirin). Ask your healthcare provider for a list of these medicines if you are not sure.

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.

Lecanemab ingredients

Lecanemab is only available as the brand Leqembi.

Active ingredient: lecanemab-irmb.
Inactive ingredients: arginine hydrochloride, histidine, histidine hydrochloride monohydrate, polysorbate 80, and water for injection.

Lecanemab is available as:

• Leqembi injection: 500 mg/5 mL (100 mg/mL) in a single-dose vial.
• Leqembi injection: 200 mg/2 mL (100 mg/mL) in a single-dose vial.

Storage

Lecanemab is only available as the brand Leqembi.

Unopened Leqembi Vial Storage:

• Store in a refrigerator at 2°C to 8°C (36°F to 46°F).
• Store in the original carton to protect from light.  
• Do not freeze or shake.

After lecanemab vial dilution

• Immediate use is recommended
• If not administered immediately, store refrigerated at 2°C to 8°C (36°F to 46°F) for up to 4 hours, or at room temperature up to 30°C (86°F) for up to 4 hours.
• Do not freeze.

Who makes lecanemab?

Eisai Inc., manufactures lecanemab under the brand name Leqembi. There is no Leqembi generic.

Lecanemab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for lecanemab.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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