The U.S. Food and Drug Administration (FDA) gave the O.K. last Friday to a new radioactive dye that helps doctors scan the brain for Alzheimer’s disease.
The dye, called Amyvid (florbetapir), made by Eli Lilly Co., binds to the sticky amyloid proteins that build up in the brains of patients with Alzheimer’s. The dye can be detected by using positron emission tomography, or PET scans.
The test could allow doctors to diagnose Alzheimer’s much earlier and more accurately. In patients with symptoms of cognitive decline, the presence of amyloid would support an Alzheimer’s diagnosis. The dye cannot be used alone to diagnose Alzheimer’s, however, especially not in people without symptoms because people with normal brain function may accumulate amyloid plaques as they age, and because the plaques can be associated with neurological conditions other than Alzheimer’s.
But if doctors do not see any protein clumps after administering the dye, they can rule out Alzheimer’s and look for other causes of cognitive problems.
“It’s estimated that one in five patients clinically diagnosed with probable Alzheimer’s disease during life do not end up having Alzheimer’s disease pathology upon autopsy,” said Dr. Daniel Skovronsky, the global brand-development leader for Amyvid at Lilly, in a statement. “The approval of Amyvid offers physicians a tool that, in conjunction with other diagnostic evaluations, can provide information to help physicians evaluate their patients.”
Last March, the FDA rejected Amyvid after an advisory panel cited concerns that doctors may have trouble reading and interpreting the scans correctly. Since then, Lilly said it has identified better ways to train doctors to use the test and is offering both online and in-person training programs. The company plans to sell the dye through its unit Avid Radiopharmaceuticals Inc.
According to Reuters, Avid is a frontrunner in Alzheimer’s imaging developments, which are estimated to have a potential global market of $1 billion to $5 billion. General Electric Co. and Bayer AG are developing rival products.
Amyvid will be available in limited quantities in June, Lilly said in its statement.