TL;DR
For most of history, Alzheimer's was something medicine met after the memory was already going. That is starting to change. A vaccine has made anti-amyloid antibodies in every older volunteer who got it, a cholesterol pill is being tested in people whose blood shows early Alzheimer's changes but whose memory is fine, and a trial in Colombia is asking whether a daily pill can keep brain plaque from growing back once a drug has cleared it. Washington rewrote its national dementia plan around prevention this month. None of it proves anything yet; the trials measure biomarkers, not memory. But the target has moved from treating dementia to heading it off, and if any of these approaches works, Alzheimer's could become something people are screened and dosed for in middle age, like high cholesterol.
Below the line, for paid subscribers: The full story: where it stands, how we got here and what's dated next; our Odds board on 6 milestones, starting with "AriBio's AR1001 pill reports a positive Phase 3 result by 2026"; our labeled speculation on what it adds up to; and every source.