Lecanemab (Leqembi®) is an antibody intravenous (IV) infusion therapy that targets and removes beta-amyloid from the brain. It has received traditional approval from the U.S. Food and Drug Administration (FDA) to treat early Alzheimer's disease, including people living with mild cognitive impairment (MCI) or mild dementia due to Alzheimer's disease who have confirmation of elevated beta-amyloid in the brain. The treatment reduces cognitive and functional decline in people living with early Alzheimer's.

Download a comprehensive toolkit based on the Appropriate Use Recommendations for Lecanemab that includes guidance on patient eligibility, appropriate dosing and administration, and amyloid-related imaging abnormalities (ARIA) management.

Patient eligibility criteria

The FDA's prescribing information specifies that lecanemab is appropriate for people living with early Alzheimer's with confirmation of elevated beta-amyloid. The treatment was studied in people living with mild Alzheimer's dementia and MCI due to Alzheimer's who showed evidence of a buildup of beta-amyloid plaques in the brain. The therapy has not been tested on people living in more advanced stages of Alzheimer's or those without clinical symptoms.

See Patient Eligibility Criteria for comprehensive inclusion and exclusion criteria.

Apolipoprotein E (APOE) genetic testing

An increased risk for ARIA is found in APOE4 carriers, so APOE genotyping is recommended for patients being considered for lecanemab therapy before initiating treatment.

See Apolipoprotein E (APOE) Genetic Testing for information on the relationship between ARIA and APOE4 carriers.

Appropriate dosing and administration

  • Administration: Intravenously (IV) every other week. No titration is required.
  • Dosing: 10/mg/kg of body weight.
  • Quantity: Vials of 500 mg/5 mL (100 mg/mL) or 200 mg/2 mL (100 mg/mL).
  • Length of infusion: Approximately one hour.

See Appropriate Dosing and Administration for information on preparation and post-infusion observation.

ARIA monitoring and management

ARIA is a common side effect of lecanemab treatment. Two types of ARIA may occur: ARIA-E with edema and ARIA-H with hemorrhagic changes.

Eligible patients must have an MRI within one year prior to initiation of treatment. Lecanemab's appropriate use recommendations propose MRI scans prior to the fifth, seventh and 14th infusions. Additionally, an MRI is recommended prior to the 26th infusion at week 52, especially in patients who are APOE4 carriers or had evidence of ARIA (with or without symptoms) on prior scans.

See ARIA Monitoring for a comprehensive guide to MRI monitoring for lecanemab.

See Management of ARIA for an ARIA care pathway, symptoms and management of ARIA based on symptom description.

See Introduction to ARIA and Its Management for a one-hour CME course.

Management of infusion reactions

Infusion reactions may occur during the first two treatments and can be seen during the infusion or up to several hours after.

See Management of Infusion Reactions for guidance on grading and management of infusion reactions.

Stopping lecanemab

Prescribing clinicians should stop lecanemab therapy for any of the following ARIA-related observations:

  • Any macrohemorrhage.
  • More than one area of superficial siderosis.
  • More than 10 microhemorrhages since treatment initiation.
  • More than two episodes of ARIA.
  • Severe ARIA symptoms.
  • Patient requires treatment with an anticoagulant.

Prescribing clinicians should stop lecanemab therapy for severe infusion reactions:

  • A grade 3 or higher infusion reaction.

See Stopping Lecanemab for more information on grading of infusion reactions.

Clinical workflow considerations

Primary care clinicians may not be able to prescribe lecanemab but play an important role in early detection and diagnosis. Regardless of whether a patient may be a candidate for this treatment, early and accurate diagnosis has long demonstrated better health outcomes for individuals living with Alzheimer’s and their caregivers. The Alzheimer's Association offers a number of tools to help, including a Cognitive Assessment Toolkit.

Specialists will need to conduct a thorough cognitive assessment and confirm the presence of amyloid in order to consider treatment with lecanemab. This process may include amyloid PET or CSF testing. When considering any treatment, it is important for patients and clinicians to have a conversation to determine if the patient is a candidate and to make an informed decision about whether the treatment is an option. Not all patients with amyloid will be good candidates for the treatment, depending on the stage of the disease and other risk factors.

See Clinical Workflow Considerations for additional resources needed for clinicians and medical centers to implement for the safe and effective use of lecanemab.