Researchers study amyloid drugs as prevention for symptom-free adults
A new type of blood test can detect brain changes associated with Alzheimer’s disease, and a growing number of patients are asking their doctors about it. For Susan Dancer, the question felt personal.
Dancer, who cares for rescued animals in Bay City, Texas, turned 60 this year and began to worry about her own brain. Her mother and grandmother both died with symptoms of Alzheimer’s disease, and Dancer, the eldest of three sisters, said the fear was difficult to live with.
“It’s extremely scary. And I just felt like, you know, I’m the matriarch of this family now. Am I next?” Dancer said.
Searching online for answers, Dancer said, led her to a new type of blood test that indicates the presence of amyloid plaques in the brain, a hallmark of Alzheimer’s. She said she checked in with her daughter, a medical research scientist, whose “knee-jerk reaction as a medical person” was not to take the test — because the result would not lead to treatment. Dancer, however, wanted to plan the rest of her life and death.
“I want to be in charge of my health myself and to shield and protect my family from having to go through what my sisters and I went through with our mother and grandmother,” Dancer said.
Dancer got the test by enrolling in a clinical trial, and a few days later an email provided the result. “The literature said that you were hoping for a number below 0.18, and my number was 0.10, roughly halfway there. So that was — I don’t think it means that I’m not going to get dementia or have issues down the road, but it was very reassuring,” she said.
The test Dancer took measures a protein called p-tau217. The approach was developed by scientists including Dr. David Holtzman, a neurologist at Washington University School of Medicine in St. Louis. “That particular test is extremely accurate at determining whether you have amyloid in the brain or not,” Holtzman said — much like a brain scan.
In September, the Food and Drug Administration approved two blood tests that measure p-tau217. But Holtzman said those tests are not meant for people like Dancer. “The currently approved tests are for people who have symptoms of the disease. They were not approved by the FDA for people who are not symptomatic,” he said.
Holtzman said that is because the two drugs that can remove amyloid from the brain are approved only for people who already have symptoms of dementia. “Right now, if you did get a test like that and you’re still cognitively normal, there’s nothing that we know medically to do about that,” he said.
For people without memory loss or other symptoms, Holtzman said, a positive test can be the source of needless anxiety. But Michael Malek-Ahmadi, a scientist at Banner Health in Phoenix, said even people without symptoms may learn something from a blood test. “Those who are at or above a certain threshold, we do know those individuals are at a higher risk for progressing to having symptoms of Alzheimer’s disease,” Malek-Ahmadi said.
Malek-Ahmadi said researchers are currently studying whether Alzheimer’s can be prevented or delayed by treating these asymptomatic people with amyloid drugs, and that amyloid testing could become standard for older patients if the approach works. “What we’re working toward is that these tests would be part of a regular screening routine for older adults and that we would identify people who have the biology of Alzheimer’s disease, just not the symptoms,” he said.
In the meantime, deciding whether to get a test at all is up to doctors and their patients.