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What is Leqembi™?

Written and medically reviewed by Dorcas Morak, Pharm.D

Updated on February 28th, 2023

Save up to 88% on your medications

> Leqembi™ is a brand of lecanemab-IRMB. It is a prescription-only monoclonal antibody indicated to treat Alzheimer's disease either alone or in combination with other medications. The U.S. Food and Drug Administration (FDA) approved Leqembi™ on January 6th, 2023, under the accelerated approval pathway for the treatment of Alzheimer's disease. This means that the drug has been shown to have potential benefits for patients with Alzheimer's disease, but more studies are needed to confirm its effectiveness. It is available as a single-dose vial in the strength of 500mg/5ml or 200mg/2ml. Leqembi is administered as an intravenous infusion after dilution.

How does lecanemab-IRMB work?

Lecanemab-IRMB is a monoclonal antibody that binds to a protein called amyloid beta, which is believed to play a key role in the development of Alzheimer's disease. By binding to amyloid beta, lecanemab-IRMB is thought to reduce the formation of plaques in the brain, which are a hallmark of Alzheimer's disease. Additionally, lecanemab-IRMB is thought to stimulate the immune system to clear amyloid beta from the brain, which may further improve symptoms.

How to use Leqembi?

The recommended dosage of Leqembi is 10mg/kg. It must be diluted and then administered as an intravenous infusion over about one hour, once every two weeks. If you miss your infusion dose of Leqembi, administer the next dose as soon as possible.

What are the side effects of Leqembi?

Possible side effects of Leqembi include:

  • hives
  • difficulty breathing
  • headache
  • confusion
  • visual changes
  • dizziness
  • nausea and vomiting
  • difficulty walking
  • fever
  • flu-like symptoms

The side effects above aren’t exhaustive; speak with your pharmacist or doctor if any side effects bother you.

Are there possible drug interactions with Leqembi?

Tell your healthcare provider about all the medicines you are using, including prescription and over-the-counter medicines, vitamins, and herbal supplements. It is especially important to tell your healthcare provider if you take medicines to reduce blood clots.

Is there a contraindication for Leqembi?

There is no contraindication for Leqembi yet. However, its use comes with some warnings and precautions that you should be aware of. Check them out here.

Is Leqembi safe for children?

It is not known if Leqembi is safe and effective in children.

Is Leqembi safe during pregnancy?

It is not known if Leqembi is safe during pregnancy. Tell your healthcare provider if you plan to get pregnant while receiving treatment.

Is Leqembi safe for breastfeeding?

It is not known if Leqembi is safe for breastfeeding. Tell your healthcare provider if you are breastfeeding.

What is the cost of Leqembi?

Leqembi can cost as much as $26,500 per year. Check to see if you are eligible for the Leqembi™ Copay Assistance Program.

If you need help affording other medications, you can use a prescription discount card from to save as much as 88%. They are simple to use and accepted in most pharmacies including CVS, Rite Aid, and Walgreens.

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