What is anti-amyloid therapy?

Anti-amyloid therapy is a treatment for early Alzheimer's disease that removes beta-amyloid, a protein that builds up into plaques in the brain. The National Institute on Aging says studies of lecanemab and donanemab, the FDA-approved drugs, showed they slowed cognitive decline in some participants over 18 months. They are approved for people with mild cognitive impairment or mild dementia due to Alzheimer's, not later stages.

The main side effect is ARIA, amyloid-related imaging abnormalities: usually temporary swelling in areas of the brain, sometimes with small spots of bleeding. The Alzheimer's Association says ARIA often causes no symptoms but can be serious, and may bring headache, dizziness, nausea, confusion or vision changes. Other side effects include infusion reactions, headaches, falls and serious allergic reactions. Doctors monitor for ARIA with MRI scans.

Two anti-amyloid drugs have traditional FDA approval for early Alzheimer's disease: lecanemab, sold as Leqembi, and donanemab, sold as Kisunla. The Alzheimer's Association says both are for people with mild cognitive impairment or mild dementia due to Alzheimer's who have confirmed elevated beta-amyloid in the brain. Doctors may order a PET scan or a spinal fluid test to check for amyloid before prescribing either one.

Medicare Part B covers part of the cost for people who meet certain medical criteria, according to the National Institute on Aging. The Alzheimer's Association says a doctor must confirm amyloid plaques and a diagnosis of mild cognitive impairment or mild dementia due to Alzheimer's, and the treating clinician may need to enter data in a registry. After the Part B deductible, people typically pay 20 percent of the approved amount.

An anti-amyloid infusion is the way these drugs are usually given: slowly through a vein at a hospital or infusion center, on a regular schedule. The Alzheimer's Association says donanemab (Kisunla) is given by IV infusion and lecanemab (Leqembi) by IV infusion or by injection under the skin. Because of the risk of ARIA, the National Institute on Aging says doctors should monitor treatment with MRI scans.