It would be interesting to see how brain function continues to be impaired even while the beta amyloids are suppressed using these drugs, helping us get to the real process.
According to my understanding of the amyloid cascade hypothesis, the amyloid beta accumulation is not a cause but indeed a symptom (of gene mutations/something). Then, the amyloid beta basically clumps up and other mechanisms happen and neurons get damaged and this collective damage is known as Alzheimer's Disease.
So the amyloid beta is just one link in the chain.
Even with a complete removal of that link (removing/reducing amyloid beta), one cannot expect the disease to be reversed, since removal of something in-between does not revert the already occured damage. But accumulation of new damage might slow down. Coupled with improved early detection even this would be very helpful to many people.
As far as I know, some modest slowing down was observed in some of the clinical trials. This could mean the amyloid cascade hypothesis isn't completely wrong.
Now, what I found really, really interesting is that first Biogen gets ca. 20 % of its market value vaporized after the aducanumab (a joint venture betwen Biogen and Eisai). This is nearly 20 billion USD. Then, Eisai informs that they still go forward with another substance called BAN2401.
The BAN2401 also targets amyloid beta, but in a different way than others (protofibrils).
So... I'm thinking here that this is either a genius move or a really dumb one. It cannot really be anything in-between. I honestly hope it'll be a genius move.
You're missing a few words here. Was it "the aducanumab trial failed"?
It's the maddening thing about biology. It's a brutal intellectual undertaking. You could have spent your life studying amyloid. Imagine sitting in your office with your stacks of papers now, considering what you have done with your life.
Science is about discovery, not outcome.