US approves first blood test for Alzheimer's

The United States gave the green light on Friday, May 16, to the first blood test for Alzheimer's disease , which could allow patients to start drugs earlier to slow the progression of this neurodegenerative disease. The test, developed by Fujirebio Diagnostics, measures the ratio of two proteins present in the blood. This ratio is correlated with the presence of beta amyloid plaques in the brain, characteristic of Alzheimer's disease, which until now could only be detected by brain scans or analysis of cerebrospinal fluid.

"Alzheimer's disease affects too many people, more than breast cancer and prostate cancer combined," said Marty Makary of the U.S. Food and Drug Administration (FDA). "With 10 percent of people aged 65 and older affected by Alzheimer's disease, and that number expected to double by 2050, I hope new medical products like this will help patients."

There are currently two approved treatments for Alzheimer's, lecanemab and donanemab, which target amyloid plaque and modestly slow cognitive decline. They do not provide a cure. Proponents of these treatments, including many neurologists, argue that they can offer patients a few extra months of independence and should be more effective the earlier they are started.

In clinical trials, the blood test produced results broadly similar to those obtained from brain scans using positron emission tomography (PET) and cerebrospinal fluid analysis. "Today's approval is an important step in the diagnosis of Alzheimer's disease, making it easier and potentially more accessible to U.S. patients at an earlier stage of the disease," said Michelle Tarver of the FDA's Center for Devices and Radiological Health. The test is approved for clinical use in patients with signs of cognitive decline, and the results should be interpreted in conjunction with other clinical information.

Alzheimer's disease is the most common form of dementia. It worsens over time, gradually robbing sufferers of their memories and independence.