Not safe or not effective I wonder. I suppose not effective from the wording. How does it get all the way to human trials before they find it doesn’t work?
It was deemed not as efficacious as they defined in their primary clinical end point.
To your question as to how it "gets all the way to human trials..." how else would you determine if it worked, if you didn't test it in humans?
This my FRiend, is one of the reasons pharmaceutical products are more expensive and the prices continues to rise. It costs enormous amounts of money to conduct clinical trials. In these Alzheimer trials, the length of time on the drug to see results was substantial; the diagnostic tests were expensive; and the disease itself is not fully understood. You couldn't just rush into a quick clinical trial without fully understanding the results.
There is other Alzheimer's research ongoing at a number of different companies, but this was definitely a setback for all involved: pharma, patients, caregivers and the medical community.