What is lecanemab?

Lecanemab is a drug that targets removal of brain amyloid, one of the proteins that builds up in the brain in people with Alzheimer’s disease. 

When was lecanemab approved and what were the results of the clinical trial?

The FDA granted traditional approval for lecanemab (Leqembi^TM) on July 6, 2023. The data for the approval were based upon a phase 2 clinical trial and supported by the results of a recent phase 3 clinical trial in which approximately 1,800 patients with Alzheimer’s disease were treated for 18 months with either lecanemab or placebo.

The group of patients in the clinical trial who received lecanemab, showed a reduction of amyloid plaque on PET scans compared with the group of patients who received placebo. Both the lecanemab group and placebo group continued to experience decline in cognition and independence, but the decline was less pronounced for patients who received lecanemab.

Some neurologists believe the differences between the two treatment groups are too small to be meaningful. Others believe there may be benefit for select patients.

Who should get lecanemab? 

This drug is approved only for patients with mild disease with a diagnosis of mild cognitive impairment due to Alzheimer’s disease or mild dementia related to Alzheimer’s disease. Patients with moderate or severe dementia or other diagnoses are not eligible. Before starting lecanemab, your doctor will need to confirm the presence of amyloid in your brain. Your doctor will order either an amyloid PET scan or spinal tap. Amyloid PET scans are not currently covered by insurance.

What are some potential risks of lecanemab? 

This drug is known to cause brain swelling or hemorrhage in about 20% of patients. These conditions may be diagnosed as either:

• Amyloid related imaging abnormality-edema (ARIA-E)
• Amyloid related imaging abnormality-hemorrhage (ARIA-H)

Patients on blood thinners may be at a higher risk for more serious side effects. Patients who have a specific genetic variation, APOE4 are also at higher risk for ARIA, so genetic testing prior to receiving treatment is required.  ARIA is also more likely to occur within the first 14 weeks of treatment. A majority of patients who develop ARIA will show no symptoms associated with it. Those who do develop symptoms related to ARIA may experience:

• Headache
• Confusion
• Dizziness
• Vision changes
• Nausea
• Difficulty walking
• Seizures

Safety monitoring for ARIA will require frequent MRI scans. (For further details, please see here for the package insert).

Infusion-related reactions can occur about 20% of people treated with lecanemab and most occurred with the first treatment. These symptoms can include:

• Fever and flu-like symptoms (chills, generalized aches, feeling shaky, joint pain)
• Nausea
• Vomiting
• Low blood pressure
• High blood pressure
• Low oxygen levels in the blood

Approximately 40% of patients treated with lecanemab also had a temporary decrease in lymphocyte count and 20% had an increase in neutrophil counts. Safety monitoring will include laboratory blood tests. (For further details, please see here for the package insert).

How is lecanemab administered?

Lecanemab requires an intravenous infusion every 2 weeks at Stanford Health Care.

Is lecanemab covered by insurance or Medicare?

A statement on Medicare coverage for Lecanemab can be found here. This will require a patient to have Medicare coverage, have the correct diagnosis of Mild Cognitive Impairment due to Alzheimer’s disease and mild dementia due to Alzheimer’s disease, and to participate in a registry. However, coverage for the required safety MRI scans, blood tests, amyloid PET or CSF for amyloid is not yet certain. Other insurance coverage is not yet known.

Is this lecanemab right for me?

Given certain questions about safety and monitoring, lecanemab may be recommended only for patients who meet certain criteria. (For further details, please see the package insert.)

Our neurologists will consider treatment for Stanford Health Care patients who are:

• Age 50-90 years
• Able to undergo frequent MRI scans
• Diagnosed with mild cognitive impairment or mild dementia due to Alzheimer’s disease
• Have PET scans or cerebrospinal fluid (CSF) which confirms the presence of brain amyloid
• Have a care partner or support for frequent visits (recommended)
• Undergo ApoE4 genotype testing

Lecanemab is not recommended for patients with:

• A history of stroke, TIA, or seizure
• MRI abnormalities with evidence of tumor or hemorrhage
• Hypersensitivity to monoclonal antibody treatment
• Bleeding disorders or those on blood thinners
• Immune conditions or those taking antibodies, immunosuppressants, or receiving plasmapheresis
• Other serious conditions such as cancer

What should I do if I am Stanford Health Care patient and believe I qualify?

If you are a Stanford Health Care patient and believe that you qualify, please contact your care team and we will place you on a list to discuss further with your care team.