Resources for Providers

Information on Leqembi (lecanemab) for the treatment of Mild Cognitive Impairment and mild Alzheimer’s disease 

About Leqembi (lecanemab) 

Leqembi, also known as lecanemab, is a drug given to patients with mild cognitive impairment (MCI) or mild Alzheimer's disease to slow the rate of decline in memory and thinking. The drug reduces clumps of proteins (made up of amyloid) that play a key role in the brain changes of Alzheimer's disease. Reducing these amyloid proteins is not a cure but does slow memory and thinking decline for those in the earliest stages of Alzheimer's disease. Leqembi is given to patients through an IV every two weeks for 18 months or longer.  

Who is it for? 

Leqembi is for people who have had clear decline in their memory and thinking and who have confirmed elevated levels of amyloid in their brain. This includes individuals who are diagnosed with mild cognitive impairment (MCI) or mild Alzheimer's disease. The drug is unlikely to help those with more advanced cognitive decline and it is not yet known if the drug helps individuals who have no memory loss but who have increased brain amyloid (we are studying this approach now in clinical trials).    

Potential Side Effects 

Like all medications, Leqembi can have side effects. These can include: 

• Dizziness 
• Headache 
• Visual changes 
• Worsening confusion 
• Brain swelling or bleeding 
• In rare cases, death 

Healthcare teams closely monitor patients receiving Leqembi to manage side effects and assess the body's reaction to the drug. Regular brain scans are mandatory, as up to 30% of patients can exhibit brain swelling and microhemorrhages, usually without symptoms. If severe side effects occur, further treatment, potentially including hospital care or anti-seizure drugs, may be required. 

Patient Selection Criteria 

If you have cognitive issues that have been documented by your physician and you are interested in determining if you are a candidate for Leqembi, you will need to complete the following tests through your physician:  

• Cognitive testing 
• You will need to complete formal cognitive testing (often called neuropsychological testing) to demonstrate measurable impairment that is in the mild range 
• Lumbar Puncture (spinal tap) 
• A spinal tap will need to be completed to test for the presence of amyloid  
• Brain MRI (within the last year)   
• You will need to complete an MRI as a safety check to assess for changes that could put an individual at high risk from the drug
• ApoE4 gene testing 
• We recommend all individuals considering Leqembi therapy have an ApoE4 gene test to help assess the likelihood of side effects. Individuals who carry a copy of the APOE E4 gene (up to 60% of individuals with Alzheimer's disease) are at a higher risk of the side effects of the drug

A Checklist for Physicians

Documented cognitive changes 

• Document a history of mild and progressive cognitive changes.  This should include the age of onset of cognitive decline, predominant symptoms, and examples of their impact on day-to-day affairs
• Cognitive testing 
• Neuropsychological testing to 1) document measurable impairments that are 2) in the mild range (for example, an MMSE score of  around 20 or above out of 30 total points)
• Lumbar Puncture (spinal tap) 
• A spinal tap will need to be completed to confirm the presence of amyloid in the brain. Spinal fluid should be tested for CSF biomarkers of Alzheimer’s disease (amyloid measures such as AB42 and tau measures of total tau and ptau181)
• Brain MRI (within the last year)  
• The MRI needs to include a GRE or SWI sequence to detect microhemorrhages
• Individuals with any of the following on MRI are not a good candidate for the drug: microhemorrhages (5 or more), macrohemorrhage (>10mm), superficial siderosis, multiple lacunar infarcts, or severe white matter hyperintensities
• Given the need for safety monitoring, individuals who are unable to obtain an MRI are not candidates for Leqembi
• ApoE4 gene testing 
• Individuals who carry the APOE E4 gene (up to 60% of individuals with Alzheimer's disease) are at a higher risk of the side effects of the drug.  Carrying the gene does not exclude someone from receiving the drug but this information is useful in considering risks vs benefits and in monitoring for side effects
• Health screen 
• Individuals with a history of brain bleeding, stroke, seizures, or who are using anticoagulants are unlikely to be a candidate for Leqembi