U.S. physicians looking to detect early signs of Alzheimer's disease now have a second tool in their arsenal with the U.S. Food and Drug Administration's (FDA) approval of Vizamyl (flutemetamol F-18 injection), a radiopharmaceutical from GE Healthcare for use with PET imaging of the brain in adults being evaluated for Alzheimer's and dementia.
Vizamyl attaches to beta-amyloid deposits, resulting in a PET image that can be used to evaluate the presence of the protein fragment, which has been associated with the onset of dementia and Alzheimer's. Beta amyloid is usually broken down by the body and eliminated, but patients with Alzheimer's disease have shown buildup of the substance, which can negatively affect neuronal function, according to GE.
A negative Vizamyl scan indicates there is little or no beta-amyloid accumulation and, therefore, Alzheimer's is probably not the cause of a patient's dementia. A positive scan indicates a moderate or greater amount of beta amyloid in the brain, but it does not necessarily establish a diagnosis of Alzheimer's or other dementia.
The FDA stressed that Vizamyl is not indicated to predict the development of Alzheimer's or to assess how patients respond to treatment for the condition, and it should not replace other diagnostic tests for Alzheimer's and dementia. Vizamyl is manufactured for GE by Medi-Physics, which is based in Arlington Heights, IL.
GE submitted two clinical studies to the FDA in support of Vizamyl that included 384 participants with a range of cognitive function. All participants were injected with Vizamyl and underwent PET scans, and the results demonstrated that Vizamyl correctly detected beta amyloid in the brain.
In September 2012, GE presented data at the European Federation of Neurological Societies (EFNS) meeting in Stockholm from four separate biopsy studies that found F-18 flutemetamol detected beta amyloid with a median sensitivity ranging from 75% to 100% and specificity ranging from 99% to 100%. A similar range was found for autopsied subjects, and visual image assessment also showed a high level of reader agreement, according to the company.
In a press statement, Kieran Murphy, president and CEO of GE Healthcare Life Sciences, said the company hopes that "Vizamyl will help advance treatment options by helping to enroll the right people into the right clinical trials, which may lead to disease-modifying medications."
The FDA noted that only healthcare professionals who have completed appropriate training should interpret Vizamyl PET images. Safety risks associated with Vizamyl include hypersensitivity reactions and the risks associated with image misinterpretation and radiation exposure, and common side effects include flushing, headache, increased blood pressure, nausea, and dizziness.
In April 2012, the FDA approved the first PET imaging agent for Alzheimer's disease, Amyvid (florbetapir F-18), developed by Eli Lilly and its subsidiary Avid Radiopharmaceuticals. Amyvid won approval from the European Commission in January 2013.
In its statement, GE noted that Vizamyl is the only PET imaging tracer for amyloid detection approved by the FDA for interpretation of color images rather than black and white. The company said it would start shipping the agent in 2014.
