Until recently, medications for Alzheimer’s disease—the most common form of dementia—helped manage cognitive symptoms but did not slow disease progression. This changed with the FDA’s approval of antiamyloid medications, a major breakthrough in treatment. Studies show these drugs slow progression by 25% to 30% when used early, specifically in mild cognitive impairment (MCI) and mild dementia.
While promising, these therapies do not stop, cure, or reverse the disease. Research continues to improve treatments and explore new approaches.
How Do Antiamyloid Medications Work?
Antiamyloid drugs are among the latest advancements in Alzheimer’s treatment. Lecanemab (Leqembi) was FDA-approved in 2023, followed by donanemab (Kisunla) in 2024. Aducanumab (Aduhelm) was the first of its kind to receive approval but was discontinued in 2024.
These drugs prevent beta-amyloid protein from forming plaques in the brain and help clear existing plaques. They mimic the action of antibodies produced by the immune system. Clinical studies show they slow cognitive and functional decline in mild Alzheimer’s but are not effective in later stages.
Scientists are exploring whether removing amyloid before symptoms appear can provide additional benefits. Combination therapies targeting both amyloid and tau proteins are also being studied.
Lecanemab is given via IV infusion every two weeks, while donanemab is administered every four weeks. Injectable forms are being developed to improve convenience.
Side Effects of Antiamyloid Therapy
Antiamyloid drugs carry risks, including infusion-related reactions such as fever, flu-like symptoms, nausea, vomiting, dizziness, shortness of breath, and heart rate changes. These effects can often be managed with premedication.
A more serious risk is amyloid-related imaging abnormalities (ARIA), which involve brain swelling or bleeding. Most individuals with brain swelling do not have symptoms, but when they do, they may experience headaches, vision disturbances, dizziness, nausea, confusion, or difficulty walking. In rare cases, severe brain swelling can lead to seizures or encephalopathy, and large brain bleeds can be fatal.
To reduce risks, the FDA recommends a brain MRI before treatment and continued MRI monitoring.
Who is Eligible for Antiamyloid Therapy?
Certain factors affect eligibility. A healthcare provider may order:
- MRI scans to detect ARIA
- Amyloid PET scans, lumbar punctures, or blood tests for amyloid protein levels
- Neuropsychological testing
- Genetic testing for the APOE gene
These tests analyze biomarkers in cerebrospinal fluid or blood to confirm Alzheimer’s and assess suitability for treatment. People with the APOE e4 gene variant have a higher risk of ARIA, especially those with two copies of the variant.
People on blood thinners or with a history of brain bleeds or strokes may not be eligible. Advanced age can also be a limiting factor. Healthcare providers use test results and medical history to determine suitability.
It is unknown whether these drugs help people at risk for Alzheimer’s who do not yet have memory loss. Research is ongoing.
No direct comparison of lecanemab and donanemab has been conducted. Donanemab requires one infusion every four weeks, while lecanemab is biweekly. However, donanemab has a higher incidence of ARIA.
These drugs require a commitment to frequent infusions, regular doctor visits, and ongoing safety monitoring.
Cost Considerations
The cost of antiamyloid medications can be high. Medicare and Medicaid often cover most expenses, but approval may require additional paperwork.
Treatment costs go beyond the drug itself and include genetic testing, brain scans, safety monitoring, and other healthcare services. Some private insurance plans cover the medication with prior authorization. Patients should check with their insurer for coverage details.
While antiamyloid drugs are a significant advancement, they do not cure Alzheimer’s. Ongoing research is crucial to improving treatments and expanding options for patients and families.
