That's been a question for a while, and comes up every time an anti-amyloid antibody reduces plaques but doesn't affect memory impairment. A number of people believe that we need to work on early detection and to start treatment as soon as possible.

Isn't early detection and early treatment the solution to a most problems. e.g. Cancer? We still need solutions for late-stage illnesses.

It's still an open question if the plaques are a cause or symptom.

If they are a symptom then that explains why removing them doesn't change anything.

And I wonder if the drug helps the elastic nature of the brain to better reroute around the damage.