EARLY PREVENTION, EARLY TREATMENT

There are no tests that can detect Alzheimer’s before symptoms appear, but researchers are getting closer.

Eli Lilly and Co is seeking U.S. Food and Drug Administration approval to sell an Alzheimer’s imaging agent for use with positron emission tomography, or PET, scans to help doctors rule out Alzheimer’s.

In January, an advisory panel to the FDA said it would consider approving the compound, but it wants the company to develop a training program to ensure radiologists can read brain scans using the compound consistently.

Lilly acquired the drug through its recent purchase of Avid Radiopharmaceuticals Inc, which has been leading a three-way race for such imaging agents with General Electric Co and Bayer AG.

The agents could have a potential global market of anywhere from $1 billion to $5 billion, according to these companies.

Scientists are also looking for signals of Alzheimer’s in cerebrospinal fluid. These tests look for two Alzheimer’s-related proteins: beta amyloid, which forms sticky plaques in the brain, and tau, a marker of cell damage. Low levels of beta amyloid in spinal fluid suggest it may be accumulating in the brain, and high tau levels suggest nerve cell death.

Some doctors already test for this to confirm that Alzheimer’s has caused a person’s dementia.

Encouraged by these steps, National Institute on Aging, part of the National Institutes of Health, and the Alzheimer’s Association in April revised the diagnostic criteria for Alzheimer’s for the first time in 27 years to recognize mild cognitive impairment as a precursor to the disease.

They also added a new research category called preclinical Alzheimer’s, the earliest stage of the disease when clumps of amyloid start to form in the brains of people who are otherwise healthy.

This stage, which occurs some 10 years before dementia sets in, is seen as the best place to intervene. It is why new imaging agents for PET scans, spinal fluid tests and so-called biomarkers that predict Alzheimer’s are becoming so important to researchers and drug companies.

“The guidelines portend a lot more than just how to diagnose Alzheimer’s today,” said Dr. Daniel Skovronsky, founder and chief executive of Avid Radiopharmaceuticals.

“I think many people now have a sense of hope that some day we can make Alzheimer’s a preventable disease, and that is through early prevention and early treatment,” he said.