The Food and Drug Administration (FDA) has announced their approval of florbetapir (Amyvid) a radioactive dye for use with positron emission tomography (PET) for visualization of the density of amyloid plaque build up in the brain. Amyvid, developed by Eli Lilly and Company and Avid Radiopharmaceuticals, Inc., a wholly owned subsidiary of Lilly, will be used to help diagnose someone who is presenting with cognitive impairment. Cognitive impairment refers to problems with memory and other other mental processes. These may reveal themselves as symptoms indicating Alzheimer's disease.
The onset and progression of dementia has long been associated with the build up of amyloid plaques and tangles, but it is not clear at the present time whether these cause or result from dementia. Many people with amyloid in their brains show no symptoms and do not necessarily go on to develop Alzheimer's.
PET scans are a type of nuclear medicine imaging that can be used to map the brain. The drug company says, "A negative Amyvid scan indicates sparse to no neuritic plaques and is inconsistent with a neuropathological diagnosis of Alzheimer's Disease at the time of image acquisition; a negative scan result reduces the likelihood that a patient's cognitive impairment is due to Alzheimer's Disease. A positive Amyvid scan indicates moderate to frequent amyloid neuritic plaques; neuropathological examination has shown this amount of amyloid neuritic plaque is present in patients with Alzheimer's Disease, but may also be present in patients with other types of neurologic conditions as well as older people with normal cognition. Amyvid is an adjunct to other diagnostic evaluations."
At present, Alzheimer's can only be accurately diagnosed at an autopsy.
Symptoms of dementia can be the result of many causes of illnesses and diseases and many people diagnosed with Alzheimer's will have had symptoms of the disease for at least two years before it is decided that it is the probable cause.
It is hoped the FDA approval for Amyvid will assist clinicians in the diagnosis of Alzheimer's, help in Alzheimer's research and in the development of more effective treatments in the future.
Published On: April 12, 2012