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FDA Approves Imaging Drug Amyvid
Amyvid is used to produce PET scans that estimate the brain ß-amyloid neuritic plaque density in patients with cognitive impairment. ß-amyloid protein is a type of protein that forms in patients with AD and some other cognitive disorders. Neuritic plaques, also called amyloid plaques, are abnormal clumps of brain cells mixed with ß-amyloid protein. A negative Amyvid scan indicates few to no neuritic plaques and reduces the likelihood that any cognitive impairment is due to AD. A positive scan indicates moderate to frequent plaques. This amount of ß-amyloid plaque can be found in patients with AD, in patients with other types of cognitive impairment, and in older people with normal cognition.
“Many Americans undergo evaluations to try to determine the cause for a decline in cognitive functioning,” says Janet Woodcock, M.D., director of FDA’s Center for Drug Evaluation and Research. “Until now, the brain content of ß-amyloid neuritic plaques could only be determined with a brain biopsy or examination of the brain at autopsy. This imaging agent is one tool to help physicians in the assessment of their patients by serving as an adjunct to other diagnostic evaluations.”
Following intravenous injection, Amyvid (a radioactive drug) binds to brain ß-amyloid. A radioactive signal is detected with a PET scanner to produce images of the plaque in the brain. A positive Amyvid scan indicates moderate to frequent plaques. However, a positive Amyvid scan does not establish a diagnosis of AD because, although patients with AD always have an increased brain content of plaque, the test also may be positive in patients with other types of neurologic conditions, as well as in older people with normal cognition.
Amyvid is not a test for predicting the development of AD-associated dementia and is not for monitoring patient responses to AD therapy. Amyvid does not replace other diagnostic tests used in the evaluation of cognitive impairment. This is a new type of nuclear medicine test and images should be interpreted only by healthcare professionals who successfully complete a special training program developed by the manufacturer. The Amyvid label includes information on interpretation of Amyvid PET images.
Common adverse reactions include headache, musculoskeletal pain, fatigue, and nausea. Safety risks include radiation risk and risks associated with image misinterpretation.
Amyvid is manufactured for Avid Radiopharmaceuticals in Philadelphia.