Nobel prizewinner Koichi Tanaka says the predictive blood test for Alzheimer’s disease he and colleagues spent almost a decade developing is a double-edged sword.
Without medications to stave off the memory-robbing condition, identifying those at risk will do nothing to ease the dementia burden and may fuel anxiety. But used to identify the best patients to enroll in drug studies, the minimally invasive exam could speed the development of therapies for the 152 million people predicted to develop the illness by 2050.
In the absence of medical breakthroughs, the worldwide cost of dementia is projected double to $2 trillion by 2030.
While scientists debate the cause of Alzheimer’s, most agree that no treatment is likely to work on patients with significant cognitive impairment. That’s because their brains have been irreversibly damaged by clumps of misfolded and abnormal proteins that jam nerve cells.
“There are many reasons why drugmakers have failed to develop a cure for Alzheimer’s disease, but it’s too late to start treatment when patients already show symptoms,” Tanaka said.
In a study published in Nature in January last year, Tanaka and colleagues showed it was possible to use a novel biomarker discovered by his lab to accurately quantify minute traces of amyloid-beta from a teaspoonful of blood, and gauge the progression of Alzheimer’s — allowing identification of people likely to develop dementia over the coming decades.
Previously, the brain changes that occur long before Alzheimer’s symptoms appear could only be reliably assessed by magnetic resonance imaging (MRI) and positron-emission tomography (PET) scans, and from measuring amyloid and another errant protein called tau in spinal cord fluid — methods that are expensive and, in the case of a spinal tap, invasive.
“Our finding overturned the common belief that it wouldn’t be possible to estimate amyloid accumulation in the brain from blood,” Tanaka said. “We’re now being chased by others, and the competition is intensifying.”
About a dozen companies and research groups from around the world, including Roche, Spain’s Araclon Biotech SL, and Lexington, Massachusetts-based Quanterix Corp., are pursuing blood-based diagnostic tools for Alzheimer’s and other neurodegenerative diseases.
“These blood tests are very important to that aim of trying to get these groups identified and ready to go into trials, and make them faster and less expensive,” said Christopher Rowe, a neurologist who heads molecular imaging research at the Austin Hospital in Melbourne. “That, in turn, is the greatest hope for having a significant impact on the epidemic.”
The global Alzheimer’s disease diagnostics and therapeutics market is predicted to reach $11.1 billion in 2024 from $7.5 billion last year, ResearchAndMarkets.com said in March.
The greatest benefit from screening blood tests for Alzheimer’s will come once treatments are available to prevent dementia symptoms, said Randall Bateman, the Charles F. and Joanne Knight distinguished professor of neurology at Washington University School of Medicine in St Louis. Bateman and colleagues presented in 2017 a new method for measuring plasma amyloid levels using a similar approach to Tanaka’s group.