Blood test predicts Alzheimer's risk; tau drug shows early promise

Researchers reported two significant developments at the Alzheimer's Association International Conference: a blood test that may predict dementia risk in healthy older adults, and an experimental drug that lowers tau protein and shows potential to slow cognitive decline.

Blood test predicts risk

A study of 2,684 healthy older adults found that those with high levels of p-tau217 in their blood had a 38% risk of developing cognitive impairment within five years, rising to 78% over 10 years Source: AP News. The test measures a form of tau that correlates with amyloid plaques Source: CNN. However, experts caution against use in healthy people currently, as the 10-year estimate is less robust Source: AP News.

Tau-targeting drug shows promise

Biogen's diranersen, an antisense oligonucleotide injected into spinal fluid, aims to reduce tau production. In a study of about 400 people, the lowest dose showed the strongest effect, reducing tau levels and showing cognitive slowing comparable to amyloid therapies Source: AP News. While the study missed its primary goal, researchers say it "reinvigorates interest" in tau mechanisms Source: AP News.

What's next

Both findings require larger trials. The blood test could eventually be used for risk assessment if preventive drugs become available, while diranersen moves to a larger phase 3 study.