Finding more effective treatments for Alzheimer’s disease, a disease that affects more than 44 million people globally, remains one of the great challenges of the 21st century. Without treatments that slow or stop the disease, the number of people affected by Alzheimer’s is expected to grow to more than 135 million by the year 2050. The high cost of caring for so many millions affected by this disease (already exceeding $600 billion per year) will place an enormous strain on healthcare systems around the world.
Discovering therapies that slow the natural progression of Alzheimer’s disease has proven difficult. Currently available Alzheimer’s medications (like donepezil and memantine) help the brain function better and improve symptoms, but do not affect the processes that cause the disease in the first place. As a result, no currently available Alzheimer’s medications slow down the disease.
What causes Alzheimer’s?
After years of research, scientists are finally beginning to unlock the secrets of what causes Alzheimer’s. It is now widely believed that the buildup of a protein called amyloid — a protein that our brain cells produce naturally throughout our lives — begins to accumulate in the brains of people who are affected. For some unknown reason, people with Alzheimer’s lose the ability to clear amyloid from the brain. When enough amyloid accumulates, it clumps together, forming plaques. Amyloid plaques are toxic to brain cells and slowly cause neurons to die. When enough neurons are affected, the symptoms of dementia appear.
Can plaque be reduced or removed by therapeutic intervention?
Over the past 10 years a number of experimental medicines, known as anti-amyloid therapies, have been developed. Several anti-amyloid therapies have been tested in people with Alzheimer’s disease in clinical trials. Unfortunately, none of these medications improved the symptoms of dementia.
Many scientists believe these failures occurred because treatment was given too late. Based on amyloid PET scans, which show amyloid levels in the brain, we now know that amyloid begins to accumulate many years (up to 25 years) before the first symptoms are noticed. Therefore, the ideal time to start an anti-amyloid therapy may be when the symptoms are very mild or even at a time point before the first symptoms appear.
What would prevention look like?
When clinical trials test medications in people before the onset of symptoms, these are called prevention studies. In order for prevention studies to be considered successful, the study must show that the therapy reduces the risk of developing Alzheimer’s. This is demonstrated by showing that participants receiving the experimental therapy developed the disease at a lower rate than those receiving a placebo. Prevention studies need to be long (usually more than five years in length) and include only people who are at very high risk of developing the disease. Family history, genetics, age and brain amyloid levels (demonstrated by amyloid PET scans) are often used to identify candidates for Alzheimer’s prevention trials.
Only about 1 in 10 people who are interested in participating in prevention trials have the right features to be included in a trial.
Prevention efforts at Cleveland Clinic Lou Ruvo Center for Brain Health
We are committed to the challenge of preventing Alzheimer’s disease and are currently conducting Alzheimer’s prevention studies.
In a world that adds a new case of dementia every four seconds, it is imperative that new and better treatments for Alzheimer’s are discovered as soon as possible. Therapies that could prevent Alzheimer’s would fundamentally alter the lives millions of people all over the world.
By Aaron Ritter, MD
If you or a family member are interested in participating in a clinical trial for the prevention of Alzheimer’s, please contact us at [email protected].
About the Author
Aaron Ritter, MD, received his Bachelor of Arts at the University of Wisconsin-Madison and obtained his medical degree from the University of Colorado. He completed an internship in pediatrics and residency training in psychiatry at the University of Arizona in Tucson, followed by a fellowship in behavioral neurology and neuropsychiatry at Cleveland Clinic Lou Ruvo Center for Brain Health, where he is now Director, Clinical Trials Program.