How a new technology might accelerate Alzheimer's testing, treatment for millions

It can take months or years for doctors to determine whether people with early signs of memory loss have Alzheimer's disease.

But experts say a new generation of blood tests may replace the expensive brain scans and spinal taps now used to diagnose the mind-robbing disease. Early diagnosis could allow patients earlier access to drugs approved by the Food and Drug Administration to treat Alzheimer's . The new blood tests may also help drug researchers more efficiently conduct clinical trials to evaluate experimental drugs aimed at slowing the incurable disease that afflicts 6.9 million Americans.

This week, researchers at the Alzheimer’s Association International Conference will report results from a series of studies evaluating these new blood tests. While blood tests are not yet widely deployed at memory clinics, new research suggests some of them have proven accurate and they could soon be introduced more broadly into medical settings.

"We know that blood tests have the potential to increase (the) accuracy of early diagnosis and maximize the opportunity for patients to access potential Alzheimer's treatments," said Dr. Rebecca Edelmayer, senior director of scientific engagement for the Alzheimer's Association. "The field is really moving forward with the use of these types of tests."

Diagnosing the memory-robbing disease isn't simple. A doctor must examine a patient and conduct memory and thinking tests. Doctors then may refer patients to specialty clinics to undergo PET scans or spinal taps to detect whether the person has a telltale buildup of amyloid-beta protein, which forms plaques in the brains of Alzheimer's patients.

Blood test outperforms doctors when diagnosing Alzheimer's

Research suggests that the new blood tests can accurately determine if someone has Alzheimer's disease. A study of more than 1,200 patients with signs of the disease found the Precivity AD2 blood test , which measures ratios of the proteins tau and amyloid-beta, detected the disease more often than doctors did.

Among two large groups of patients who visited specialized memory clinics or primary-care clinics, the Precivity test accurately detected 90% of cases, even among patients with complicated medical histories including kidney disease, according to a study published Sunday in the Journal of the American Medical Association. By comparison, specialists at the memory clinics identified 73% of cases and primary-care doctors accurately diagnosed 63% of cases.

Experts said they are encouraged by the finding that blood tests could improve the accuracy of diagnosis across a broad spectrum of physicians, including specialists and primary care doctors. Many patients might not have access to memory clinics or specialized tests – such as PET scans that visually detect amyloid-beta plaques or spinal taps to get cerebrospinal spinal fluid samples.

"The big promise for blood tests is that they will eventually be accessible, hopefully cost-effective and non-invasive," Edelmayer said.

The PrecivityAD2 test uses a technology called mass spectrometry to measure ratios of phosphorylated tau and beta-amyloid proteins to determine whether a person has the disease. The test is made by St. Louis-based C2N Diagnostics. The company mails test kits to doctors and researchers who return samples to the company's labs to perform the test.

The company is permitted to market the test, under Food and Drug Administration rules, because testing is performed at the company's lab, which is certified under the Clinical Laboratory Improvement Amendments, the federal laboratory law known as CLIA. Mayo Clinic also offers the test.

The list price is $1,450. Insurance plans do not routinely cover the test. C2N officials said a top priority is to build scientific evidence and work with insurers to obtain formal coverage.

The PrecivityAD2 test is among dozens of diagnostics being developed and evaluated by researchers. Another testing company, ALZpath, has licensed its technology to large commercial companies such as Roche and Beckman Coulter. The goal for ALZpath is to widely deploy its proprietary tau test through commercial testing platforms already used in hospitals and other medical settings.

"Our belief is that we are going to see a complete transformation in how Alzheimer's is diagnosed, and that's really driven by the treatments that are becoming available," said Chad Holland, CEO of ALZpath.

Blood tests can detect disease before memory and thinking problems surface

Another study released Sunday found that tau blood tests can identify people likely to be in the early stages of the disease even though they have shown no signs of memory and thinking problems.

Researchers from Lund University in Sweden analyzed samples from more than 2,700 cognitively normal people across 10 studies. The samples included both tau in blood and amyloid-beta, detected by PET scans or spinal taps. The study concluded the tau tests could predict 79 to 86% of cases in which cognitively normal people also had a buildup of amyloid-beta confirmed by PET scans or spinal taps.

If that study's findings are confirmed, researchers said it might show that tau blood tests could reduce the need for experts to use expensive PET scans or spinal taps to screen patients for Alzheimer's medical studies.

“Our results support that plasma p-tau217 positivity alone may be sufficient as a selection of cognitively unimpaired, amyloid-positive participants for many clinical trials,” said Gemma Salvadó, a lead author of the study and an associate researcher at Lund University.

Quicker access to Alzheimer's disease drugs

Experts anticipate that aging Americans will begin demanding these blood tests now that new Alzheimer's drug treatments are hitting the market.

Earlier this month, the FDA approved Eli Lilly's Alzheimer's drug donanemab, shown in studies to slow the early stages of the disease. The drug, which will be sold under the brand name Kisunla, is an antibody that removes beta-amyloid that accumulates in the brains of patients with Alzheimer's disease. Clinical studies showed people with a mild form of the disease reduced cognitive decline by 35% compared with those who took a placebo.

Last year, the FDA approved Eisai and Biogen's drug Leqembi, which also slowed cognitive decline in people with early stages of the disease.

People in the early stages of the disease must undergo tests to confirm they carry amyloid-beta before they are prescribed these new medications. However, experts say these tests are often delayed or inequitably deployed because there's a shortage of Alzheimer's specialists and many people can't access clinics that can perform PET scans or spinal taps to detect amyloid-beta.

Research set to be presented at the conference says tau blood tests empower primary care doctors to diagnose the disease more efficiently and reduce wait times for patients to get new Alzheimer's drugs. Until the advent of these tests, doctors relied on cognitive tests and referred patients to specialists as needed. Because there's a shortage of specialists and limited capacity to test using PET scans and spinal taps, patients sometimes wait months or years to find out whether they have Alzheimer's or other debilitating conditions.

As the number of aging Americans grows, the need for quicker diagnosis becomes more pressing, experts say. A study presented at the Alzheimer's Association conference this week projects that without blood test diagnoses, by 2033 people would wait an average of nearly six years to find out if they are eligible for Alzheimer's medications. However, if blood tests are deployed by primary care doctors to rule out Alzheimer's, wait times to see a specialist could be reduced. The study led by the University of Southern California projects the average wait time to get a diagnosis would be reduced to 13 months.

Edelmayer said the Alzheimer's Association plans to update guidance for doctors and researchers this week on the appropriate use of blood tests for Alzheimer's. When the guidance was last updated in 2022 , the Alzheimer's Association said these blood tests were valuable for research but noted that memory clinics should be cautious when using them. The association also said the tests should not be used to broadly screen populations or be sold directly to consumers.

Nicholas Ashton, a neuroscientist at Banner Health in Phoenix, said blood tests have become standard in academic research circles. They're advancing at a "fast-moving pace" and Ashton anticipates they can gain wider use at a lower cost in medical settings.

"This is exactly where we need to be," Ashton said.

Ken Alltucker is on X at @kalltucker, contact him by email at alltuck@usatoday.com .

This article originally appeared on USA TODAY: How a new technology might accelerate Alzheimer's testing, treatment for millions