Understanding risks

Many people with Alzheimer's disease cannot take lecanemab or donanemab because of several factors that increase the risk of serious side effects. Talk to your healthcare professional about your risk profile.

Your medical team will likely recommend a genetic test to understand your risk. A gene called APOE comes in a few different forms. APOE e4 increases the risk of developing Alzheimer's disease. People who carry one copy of APOE e4 also have an increased risk of brain swelling or bleeding. People with two copies of APOE e4 have a greater risk.

Many factors rule out the use of lecanemab and donanemab, including:

• Stroke, ministrokes or heart attack within the past year.
• Immune system diseases, such as rheumatoid arthritis or Crohn's disease.
• Other diseases requiring medicines, called monoclonal antibodies, that are based on the same basic science as lecanemab.
• Use of blood-thinning medicines.
• History of drug or alcohol misuse or dependence in the past two years.
• Other medical conditions that are not well-managed.
• Recent history of cancer.