Blood Tests for Alzheimer’s Disease Are Showing Promise

Mucke disagrees with others in the field who maintain that some amount of tau is important for maintaining the normal structure of neurons; based on his work with animals, he believes that if disease processes like those involved in Alzheimer’s disease start to appear, then tau becomes an enabler to the disease, essentially fueling the abnormal mechanisms along. “There are probably quite a few functions that tau is involved in that, under normal circumstances, don’t do anything bad,” he says. “But if a disease comes along—not only Alzheimer’s, but epilepsy and autism spectrum disorders—tau reduction can dampen the down processes that lead to these diseases.”

Debate on this point can, and should, continue, says Mucke. But the important lesson of the study, he adds, is that reducing tau matters, regardless of how it might be involved in the process of Alzheimer’s disease.

The study is still an early trial of the experimental drug. But if diranersen’s effects are confirmed by more studies, which Biogen says it plans to conduct, then VandeVrede can imagine a future where the drug might one day be taken alongside an anti-amyloid drug. (The ones currently on the market can at best slow cognitive decline by about 30%.) “If we see the benefit of tau, then my instinct is that clinicians will think, ‘What if we use both?’” says VandeVrede. “If you slow down something with a drug, and can then slow it down again with another drug, you end up with something that may look like stabilization. And that would be a huge win in the Alzheimer’s world.”