Introduction to Alzheimer's Disease Modifying Medications

Until very recently, the only medications available to those living with Alzheimer’s were those that addressed symptoms. As we discussed last week, while these may improve the quality of life, they do not alter the trajectory of the disease.

That all changed in 2021 when the FDA approved the first medication designed to modify the underlying cause of the disease. This medication was shown to reduce amyloid plaques, one of the two hallmark proteins associated with Alzheimer’s disease..

Today, there are two FDA‑approved disease‑modifying medications for Alzheimer’s disease. When given to people with mild cognitive impairment or mild Alzheimer’s dementia, these treatments slow cognitive and functional decline by approximately 30% over 18 months, compared with placebo. While these medications are not a cure, they may allow some individuals to maintain independence for a longer period of time. If you think you or your loved one may qualify, please talk with your doctor..

Lecanemab

First approved by the FDA in 2023, lecanemab, or Lequembi, is administered through IV every two weeks for eighteen months. Clinical trials showed that reducing amyloid in the brain can modestly slow cognitive and functional decline in early Alzheimer’s disease...

Donanemab

Donanemab is also administered through IV, but every four weeks instead of every two. The FDA approved donanemab for those living with mild cognitive impairment and mild dementia due to Alzheimer’s disease in 2026. It was the third medication that showed removing amyloid from the brain can slow cognitive decline.

Side Effects

Lecanemab and donanemab carry risks. Side effects include flu-like symptoms such as:

• Nausea
• Vomiting
• Dizziness

More serious side effects include brain swelling or bleeding (ARIA), with higher risk in individuals who carry the APOE ε4 gene.. Before prescribing someone either drug, a physician will review their medical history and take images of the brain to confirm the presence of amyloid and ensure they qualify for the drugs.

Some factors that may make these medications unsafe or inappropriate include:

• A recent stroke
• Use of anticoagulant blood thinners
• Recent history of cancer.

The Future

This is an exciting time in Alzheimer’s research. Ongoing studies are testing whether disease‑modifying therapies can be given earlier—before symptoms begin—to delay or prevent cognitive decline. Other trials are targeting tau, the second hallmark protein of Alzheimer’s disease, as well as inflammation and other disease pathways. Researchers are also exploring combination approaches that target multiple disease pathways at once, with the goal of achieving greater and more durable benefits than any single therapy alone.

What about other dementias?

Currently, there are no FDA‑approved medications that modify the underlying disease process in Lewy body dementia (LBD) or frontotemporal degeneration (FTD).. Clinical trials are underway to treat the underlying causes of LBD, and research into FTD is gaining traction. We hope that in the coming years, those living with LBD and FTD will have access to therapies that not only address symptoms but also the underlying causes of the disease.