1. In vitro petri dish testing is a million light years away from showing a compound works in humans.
2. This is a particularly bad problem in brain diseases as getting your compound to cross the blood-brain barrier in correct therapeutic quantities is extremely difficult.
3. We have lots of direct antibodies that kill beta amyloid in vivo that are very advanced in human trials. The problem now is that they often cause micro-damage when removing various forms of amyloid protein or have been shown to be administered far too late when the damage is already done.
4. It's still not clear that beta amyloid is even the main causal agent of Alzheimers!
In general, if you see someone touting a low effort, pre-clinical study as major medical breakthrough, start hitting the downvote button. I'm disappointed this even got to the main page.