Alzheimer’s disease has proved to be a tricky target, and researchers and drug developers have been pursuing effective treatments for decades. Debates rage over the disorder’s underlying causes, and various approaches have faced one hurdle after another. But the field has reached a turning point. Over the past four years the U.S. Food and Drug Administration has approved several therapies that address some of the condition’s potential biological roots rather than merely mitigating symptoms—a key scientific milestone. Despite the advances, however, there is still a long list of open questions and so much work to be done.
The brains of people who die with Alzheimer’s show a distinct biology: clumps or “plaques” of amyloid beta proteins in spaces between neurons and tangles of tau proteins that accumulate primarily within the nerve cells. One prevailing theory holds that amyloid builds up early, and tau tangles develop when nerve cell damage is underway but cognitive symptoms are not yet apparent. Over time these pathogenic, or disease-causing, proteins disrupt nerve cell communication. The newest treatments—lecanemab and donanemab—bind to amyloid beta proteins, clear them from the brain and modestly slow cognitive decline.
But the progression from disease-linked proteins to actual dementia is long and inexact, and amyloid and tau proteins accumulate in people with other neurodegenerative disorders, too. With Alzheimer’s there is often a 20- to 30-year lag between the initial detection of amyloid and obvious cognitive decline. According to one study that predicted disease risk based on demographic data, death rates and amyloid status, fewer than one quarter of cognitively healthy 75-year-old women who test positive for amyloid in a spinal fluid analysis or positron-emission tomography (PET) brain scan will develop Alzheimer’s dementia during their lifetime. Such findings suggest that amyloid alone is not driving disease progression and have spurred scientists to investigate other strategies.
Alzheimer’s Drugs Are Finally Tackling the Disease Itself. Here’s How
— Global Health Observ (@GlobalPHObserv) September 16, 2025
While our understanding of Alzheimer’s disease is far from complete, the latest therapies, and others in more than 100 clinical trials, offer new hopehttps://t.co/8XvYneCgSy