Drugmakers Are Testing Ways to Stop Alzheimer’s Before It Starts

When someone develops high cholesterol, doctors don’t wait until the patient’s arteries are clogged to start treatment. They prescribe cholesterol-lowering drugs while the person is still healthy to prevent plaque buildup and stop heart attacks.

Now some of the world’s biggest drug companies are trying to do something similar for millions of aging baby boomers at risk of Alzheimer’s disease. In massive final-stage trials under way at Eli Lilly Co. and Eisai Co., researchers plan to test brain-plaque-removing drugs on thousands of healthy adults. The hope is to stave off cognitive decline before it begins, or at least delay ...