Blood test can predict dementia. Trouble is, there's no cure

Tokyo

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.

"We must be cautious on how the test is used because there's no curative treatment," Dr Tanaka said in an interview at Kyoto, Japan-based Shimadzu Corp, where he's worked for 36 years.

The 59-year-old engineer, who shared the Nobel for chemistry in 2002, said he hopes the test he helped pioneer will one day be administered routinely, but right now it belongs in the hands of drug developers and research laboratories.

In the absence of medical breakthroughs, the worldwide cost of dementia is projected double to US$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," Dr Tanaka said.

In a study published in Nature in January last year, Dr 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. BLOOMBERG