Published on: December 14, 2014
by Megan Scudellari for Bloomberg News:
Before Alzheimer’s begins to steal the mind, hints of the disorder circulate in the blood, potentially giving people a way to find out whether they’ll fall victim to the disease years in the future.
The question is: Would you want to know?
This year, research teams announced blood tests under development to diagnose Alzheimer’s before symptoms arise, including one that predicted the disease’s onset with 100 percent accuracy a decade in advance. While the tests will likely help drug companies evaluate medicines, they’ll also create wrenching personal and ethical dilemmas for patients who will have to live with the knowledge that they’re destined to develop the disease, the sixth-leading cause of death in the United States, according to the Alzheimer’s Association.
For patients like Pamela Freeman’s mother, knowing Alzheimer’s was coming would have been a “tremendous help” to her family. About age 75, her mother began to make unexplained, nonsensical purchases, stashing boxes all over the house. A relative talked her into a bad investment. “She never would have done this when she was in her right mind,” Freeman said. By the time the family realized she had Alzheimer’s and needed help, three years later, $10,000 was gone.
A predictive test might have changed that. “Had we known it was coming, there would have been a lot better outcome,” Freeman said. Before she died at age 87, her mother ran out of money, and Freeman and her siblings had to help cover her expenses.
A test could help families like Freeman’s plan ahead and open up new areas of treatment for drugmakers. But there are consequences to such foresight. Knowing the mind will decay into memory loss and dementia may put some patients at an increased risk of suicide or have them turn in desperation to false cures that could hurt their health, said Craig Klugman, a bioethicist and chairman of the Department of Health Sciences at DePaul University in Chicago.
“Living in fear will change how a person lives their life,” said Klugman. “Personally, I would urge people not to know.”
So far, it’s a question that exists only in theory. The researchers developing the tests have used blood samples taken years or a decade ago, analyzing their molecular signals to identify which patients developed Alzheimer’s. They haven’t yet used the test in the present to make a diagnosis on the future.
Doctors who treat Alzheimer’s patients have experience breaking the news to them while they’re still lucid, though not the years ahead of time that a predictive test would allow.
Alireza Atri, a neurologist in the memory disorders unit at Massachusetts General Hospital, specializes in early-onset Alzheimer’s. A predictive test could help people at risk, he said. “Nobody wants to have the diagnosis, but if counseled and supported properly, people can be relieved. There is usually something they can do about it; they can take charge, prioritize and prepare for things earlier when lifestyle changes are more likely to produce a benefit.”
Those changes include exercising both the body and mind regularly, eating a balanced diet, sleeping well and decreasing one’s level of stress to delay the start or severity of symptoms, or to lower the chances of developing them. Even without a cure, patients and families are often relieved to know what’s happening, said Atri. “I oftentimes get big hugs after I diagnose someone,” he said. If there were a predictive test, “I’d do it myself.”
Freeman and others like her say they can handle the knowledge. “If I do have Alzheimer’s, I will accept it. It’s my lot in life,” she said.
If Freeman had a positive diagnosis, she could plan for her own care or join a clinical trial to help find a cure for the disease, she said. “I probably won’t see a cure in my lifetime, but possibly my younger brother, who is only 50, might. I’ll do whatever it takes to prevent it for him.”
Alzheimer’s is the most common form of dementia, and the number of people age 70 and higher with the disease is projected to more than double in the next 40 years, from 3.6 million to 9.1 million. During that same time period, annual costs associated with Alzheimer’s care will quintuple to $1.5 trillion, according to a recent analysis by researchers at the University of Southern California.
A hallmark of the disease – that it does its damage quietly, perhaps irreversibly, before patients begin to show exterior signs – has stymied drugmakers seeking a medicine.
Predictive tests, though, could identify patients to enroll in clinical trials before they have symptoms. The current leading hypothesis among pharmaceutical companies is that beta amyloid, a protein fragment that forms plaque tangles in the brain, is a key component in Alzheimer’s disease.
Experimental drugs by Eli Lilly, Pfizer, Johnson & Johnson and Elan Corp. targeted the protein but haven’t proven themselves effective in trials of patients already showing symptoms.
Those drugs may have failed because they were tested in people whose brains are already damaged. It could be the case that almost any Alzheimer’s drug, no matter how powerful, has little chance to halt disease progression once the illness is far enough along to show symptoms, like trying to stop a train speeding down a mountain. A predictive test could solve that problem.
While there are already some biomarkers identified that can detect Alzheimer’s, they require invasive, expensive and often time-consuming tests based on spinal fluid or brain scans. A blood test would be “truly useful” for drug development, said Sarah DeRossett, a senior medical director in neurosciences at GlaxoSmithKline who has conducted numerous clinical trials for the pharmaceutical company.
Until there’s a cure, though, Klugman, the ethicist, said that the tests shouldn’t be part of standard screening for the public. “It needs to be strongly regulated, and only offered to people who are at risk with a family history,” he said, or those who are already showing symptoms and seeking a definitive diagnosis.
After the Georgetown University School of Medicine published details of its test, which can predict with 90 percent accuracy whether a person will develop mild cognitive impairment or Alzheimer’s disease within three years, Executive Dean Howard Federoff said he got thousands of e-mails about it. “When I talk about it to the public, so many people want to be tested,” Federoff said.
Along with the Georgetown test, a second, published in August by King’s College London, measures whether a patient with mild cognitive impairment will develop Alzheimer’s within a year, with an accuracy of 87 percent. A third, presented last month by researchers with the U.S. National Institute on Aging, or the NIA, diagnosed Alzheimer’s as far as 10 years in advance with 100 percent accuracy, albeit in a small study of 174 people.
The three blood tests measure a variety of biomarkers: the Georgetown test identifies 10 lipids, small pieces of cell membranes; the U.K. test pinpoints 10 proteins in blood plasma; and the NIA’s test measures a brain protein found in the blood and involved in insulin signaling.
The Georgetown team has refined their panel of biomarkers to include 16 more molecules. Now, the team is ready to validate the test with larger studies, and use it in a clinical trial. “I’m getting impatient,” said Federoff. “The field needs to move forward.”
The Alzheimer’s Association is eagerly in favor of early diagnosis, said Niles Frantz, a spokesman for the nonprofit organization, but remains “extremely cautious” about the accuracy and use of the blood tests.
If a test does become available, others say they’d rather not take it. Dawn Powell, 60, is an investor relations coordinator in New York; her mother was diagnosed with Alzheimer’s this year at age 84. “Seeing as they don’t have a cure, I cannot say I’d be jumping at the chance to know if I would get it or not.”
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