Avid Radiopharmaceuticals PET SCAN based Diagnostic Test for Alzheimers Approved by FDA Committee
The First ever test – a Brain Scan developed by Avid Radiopharmaceuticals– to detect the characteristic Amyloid plaques of Alzheimer’s Disease in living person was unanimously approved by an FDA advisory committee (reports the NYTimes.com) . As per one Alzheimer’s expert, Dr. Doraiswamy, this represents a “Major Landmark for the field.”Which indeed it is.
This will be the first time that doctors would be able to visualize the characteristic deposits, known as Amyloid plaques, in living Alzheimer’s patients (till now these plaques could only be confirmed by doing an autopsy). For more than five million Americans who have Alzheimer’s disease, this is great news. And this news comes along with the recent announcement of a spinal blood test that can be used to diagnose the presence of the Amyloid plaques. In fact, results from the clinical trials for both the test are to appear in the prestigious Journal of American Medical Informatics shortly.
How Does the Avid PET Scan Work?
The brain scan test uses a special dye that has been developed by Avid Radiopharmaceuticals ( now owned by Eli Lilly). The radio-active dye attaches to the beta Amyloid plaques in patients’ brains, making it visible on PET scans. To prove that the dye indeed attaches to the plaque tissue and not other parts of the brain, researchers conducted a clinical trial involving 152 people nearing the end of life who agreed to have a brain scan and a brain autopsy after they died. The purpose of the study was to determine whether the scans would show the same plaques as the autopsies.
It turns out that 29 of the patients in the study died and had brain autopsies. In 28 of them, the scan matched the autopsy results. This suggests that the test has a high sensitivity to detect the plaque. This is a major development in the field because till now the diagnosis of the disease was made purely on patient symptoms and observation. By using the scan, doctors can now have greater confidence in their ability to diagnose the disease as many times its diagnosed at a much later stage. For instance, Alzheimer’s had been diagnosed in ONLY half of the 29 patients; the others had received other diagnoses.
This development follows the series of some major breakthroughs that have been recently announced with respect to Alzheimer’s Disease. As mentioned earlier, one was in relation to the development of the spinal fluid test for detection of beta Amyloid. And the other more recently was the discovery by Dr. Randall Bateman of the reduced clearance of Amyloid as the basis of plaque formation