Skip to main content

Leqembi

Generic name:  lecanemab-irmb
Dosage form: injection, for intravenous use

Medically reviewed by Judith Stewart, BPharm. Last updated on Jan 6, 2023.

What is Leqembi?

Leqembi is a prescription medicine used to treat people with Alzheimer’s disease.

Leqembi is an amyloid beta-directed antibody that is thought to work by selectively binding to neutralize and eliminate amyloid-beta (Aβ) aggregates that contribute to the progressive loss of neurons in Alzheimer’s disease.

What is Leqembi used to treat?

Leqembi is used for the treatment of Alzheimer’s disease, a disorder of the brain that causes memory loss over time.

Recent research suggests that the amyloid beta peptide is the main component of amyloid plaques found the the brains of people with Alzheimer's disease, and that Alzheimer’s disease is thought to progress via the accumulation and aggregation of amyloid beta. By neutralizing and eliminating the amyloid beta aggregates, Leqembi is thought to slow down the progression of Alzheimer’s disease.

It is not known if this medicine is safe and effective in children.

Important information

Leqembi can cause serious side effects including:

  • Amyloid Related Imaging Abnormalities or “ARIA”. ARIA is a side effect that 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
    • seizures

Your healthcare provider will do magnetic resonance imaging (MRI) scans before and during your treatment to check you for ARIA. 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.

Call your healthcare provider or go to the nearest hospital emergency room right away if you have any of the symptoms listed above.

Before receiving Leqembi

Before you start treatment, tell your healthcare provider about all of your medical conditions, including if you:

  • are pregnant or plan to become pregnant. It is not known if Leqembi will harm your unborn baby. Tell your healthcare provider if you become pregnant during your treatment.
  • are breastfeeding or plan to breastfeed. It is not known if lecanemab-irmb (the active ingredient) passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while receiving Leqembi.

What other drugs will affect Leqembi?

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Especially tell your healthcare provider if you take medicines to reduce blood clots from forming (antithrombotic 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.

How will I receive Leqembi?

  • Leqembi is given by a healthcare provider through a needle placed in your vein (intravenous (IV) infusion) in your arm.
  • An infusion is given every 2 weeks. Each infusion will last about 1 hour.
  • If you miss an infusion, you should receive your next dose as soon as possible.

Dosing information

Usual Adult Dose for Alzheimer’s disease

- The recommended dosage is 10 mg/kg that must be diluted then administered as an intravenous infusion over approximately one hour, once every two weeks.

Comments:
- Confirm the presence of amyloid beta pathology prior to initiating treatment.

Use:
- treatment of Alzheimer’s disease. Treatment should be initiated in patients with mild cognitive impairment or mild dementia stage of disease, the population in which treatment was initiated in clinical trials. There are no safety or effectiveness data on initiating treatment at earlier or later stages of the disease than were studied. This indication is approved under accelerated approval based on reduction in amyloid beta plaques observed in patients treated with Leqembi. Continued approval for this indication may be contingent upon verification of clinical benefit in a confirmatory trial.

Leqembi side effects

Leqembi can cause serious side effects, including:

  • see Important information
  • Infusion-related reactions. Infusion-related reactions are a common side effect which can be serious. Tell your healthcare provider right away if you get these symptoms during an infusion:
    • 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 Leqembi infusions to decrease your chance of having an infusion-related reaction. These medicines may include antihistamines, antiinflammatory medicines, or steroids.

The most common side effects include:

  • infusion-related reactions
  • headache
  • swelling in areas of the brain, with or without small spots of bleeding in or on the surface of the brain (ARIA)

These are not all the possible side effects. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

General information about the safe and effective use of Leqembi.

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. You can ask your pharmacist or healthcare provider for information that is written for healthcare professionals.

There is a registry that collects information on treatments for Alzheimer’s disease. The registry is named ALZ-NET (Alzheimer’s Network for Treatment and Diagnostics). Your healthcare provider can help you become enrolled in this registry.

What are the ingredients in Leqembi?

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

More about Leqembi (lecanemab)

Related treatment guides

Further information

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