Key points from article :
Biogen halting two phase three clinical trials of an Alzheimer's drug.
Aducanumab targeted the buildup in the brain of beta-amyloid.
Early results showed improved cognitive function and reduced amyloid in the brain.
Amyloid deposition starts a decade or so before symptoms and it's too late to treat it then.
Decision to stop the aducanumab trials was not due to any safety concerns.
Futility analysis found the trials were unlikely to meet their primary goals at completion.
