By Rosanna Sutherby, PharmD
June is Alzheimer’s and Brain Awareness Month, and the past decade has seen exciting research and advancements affecting the diagnosis and treatment of Alzheimer’s disease and dementia.
According to the Alzheimer’s Association, in 2020, approximately 5.8 million Americans age 65 and older are living with Alzheimer’s. Eighty percent are 75 years or older. As the American population ages, the number of people with Alzheimer’s dementia will increase. It is projected that by the year 2050, 13.8 million Americans age 65 and older will have Alzheimer’s disease.
These alarming numbers have spurred scientists to advance research in Alzheimer’s treatment and diagnostic tests.
Until recently, an Alzheimer’s diagnosis was only possible through an autopsy. During the last 10 years, researchers have developed screening tools for diagnosing Alzheimer’s while the patient is alive. Being able to recognize the disease early gives doctors and scientists the ability to develop drugs that target critical characteristics of Alzheimer’s dementia.
A significant way to identify Alzheimer’s is by using biomarkers that reveal key characteristics of the disease. The first biomarker approved for diagnosing Alzheimer’s disease is the beta-amyloid positron emission tomography (PET) scan.
A characteristic of the brain of a person with Alzheimer’s disease is the formation of abnormal levels of beta-amyloid protein. This protein occurs naturally in the brain, but in Alzheimer’s disease, clumps of beta-amyloid (beta-amyloid plaques) form between neurons (brain cells) and interfere with brain signals.
The beta-amyloid PET scan allows doctors to see if beta-amyloid plaques are present in a patient’s brain. Knowing this information dramatically improves scientific research on treatment. Developing and using drugs that can break up or clear beta-amyloid plaques has moved to the forefront of Alzheimer’s research.
In May of this year, the U.S. Food and Drug Administration (FDA) approved a new biomarker for use along with a PET scan to diagnose Alzheimer’s. Tauvid (flortaucipir F18 injection) is a radioactive tracer that binds to tau protein tangles in the brain and makes them visible under a PET scan.
Tau proteins help transport nutrients and other substances from one part of the brain cells to another. In Alzheimer’s disease, tau proteins collapse and form tangles that interfere with the transmission of nutrients through the neurons. Without the necessary nutrients, brain cells deteriorate and die.
Both beta-amyloid plaques and tau tangles must be present to diagnose Alzheimer’s disease. Tauvid is the first biomarker approved that can help visualize tau tangles in the brain. This important advancement is crucial in helping develop drugs that target this particular Alzheimer’s pathology.
Since the late 1990s, over 100 drugs have been tested for treating Alzheimer’s disease. Of those, only four medications have emerged from clinical trials for the treatment of Alzheimer’s dementia:
These medications have been moderately effective at reducing symptoms of Alzheimer’s dementia, but they have not been successful in stopping disease progression. New advances in Alzheimer’s treatment aim to slow or stop the progression of Alzheimer’s disease by reducing or breaking up beta-amyloid plaques or tau protein tangles.
Researchers are investigating the use of three monoclonal antibodies to reduce the number of amyloid plaques in the brain and modify the progression of the disease. The following are the three drugs under investigation:
Additional compounds are under investigation to determine if they can prevent or delay the onset of Alzheimer’s symptoms. These agents work by preventing the accumulation of beta-amyloid in the brain or by inhibiting the enzyme that makes beta-amyloid protein.
A vaccine that targets tau protein tangles is currently under investigation. It works by stimulating the body’s immune system to attack tau protein tangles. This vaccine shows promise in potentially stopping the progression of Alzheimer’s disease.
Despite previous failures of some drugs studied to treat Alzheimer’s disease, researchers continue to look for ways to target hallmark characteristics of Alzheimer’s and prevent or stop the progression of the disease. Successful treatment may require multiple drug therapies in the same way that several agents are used in combination with HIV/AIDS and cancer treatment.
Rosanna Sutherby is a freelance medical writer who has been a practicing pharmacist in her community for close to 20 years. She obtained her Doctor of Pharmacy from Nova Southeastern University in Ft. Lauderdale, FL. She utilizes her clinical training in the pharmacy, where she helps patients manage disease states such as asthma, diabetes, heart disease, hypertension, and many others. Dr. Sutherby reviews and recommends drug regimens based on patients’ concurrent conditions and potential drug interactions.