Stopping Alzheimer's Before It Starts

Rather than treating patients already stricken, new drugs from Eli Lilly and Eisai are being tried years earlier

- Robert Langreth

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 it.

The quest for a treatment has been littered with one failure after another. Only in the past two years has a new generation of anti-Alzheimer's agents started to show hints of slowing the disease's progress. But even the most promising drugs, including compounds from Eisai and Eli Lilly now under review by the US Food and Drug Administration, slow cognitive decline by only about 30% when given to people who already show symptoms.

That's because, by the time people develop obvious signs of Alzheimer's, damage to key brain areas may already be extensive. Recent brain-scan studies suggest toxic proteins, including one called amyloid that's the target of most of the new drugs, accumulate in the brain as long as two decades before they lead to dementia.

Neurologists hope that removing amyloid before it has time to cause damage will provide a greater impact for patients. If the concept pans out,

healthy adults in their late 50s or early 60s could routinely take blood tests or specialized brain scans that search for buildup of amyloid or tau, another aberrant protein. If positive, they'd then have to decide whether to go on amyloid-lowering drugs to reduce the odds of developing dementia in the distant future.