How helpful will new FDA approved test for Alzheimer’s be?
The contradictory nature of new studies and approaches to fight Alzheimer’s disease can be mindboggling. Just as a new approach seems to show great promise, follow up information can seem to throw cold water on it, diminishing the promised results.
Case in point: on April 9, 2012 a Wall Street Journal online article announced that the FDA has approved a test a that detects protein levels in the brain indicating Alzheimer’s disease.
The test uses a chemical developed by Eli Lily, combined with a PET scan. The article says that “...a chemical called florbetapir, known by the brand name Amyvid, which is a radioactive agent that tags clumps of a sticky substance called an amyloid...hallmarks of Alzheimer's disease. The chemical…then is detected using a brain imaging technique called positron emission tomography, known as PET scans.”
A year ago, the FDA declined approval of Amyvid because not enough doctors were trained in reading the results of the chemically assisted PET scan. Eli Lily has subsequently worked with the FDA to develop a training program for doctors.
How much will this test contribute to the fight against Alzheimer’s?
Also on April 9, 2012, Forbes.com published an article on the same topic. The article, titled Why Eli Lilly's Alzheimer's Imaging Test Is No Breakthrough, focused on several points which underscore the fact that this test is not definitive and may not be cost effective.
One reason for Forbes’ reluctance to get too excited about the new product is this statement which Forbes says comes directly from the Eli Lily drug label: “A positive Amyvid scan does not establish a diagnosis of AD or other cognitive disorder.”
The Forbes article says that “In a 59-patient study in which a patient’s Alzheimer’s status was later determined by autopsy, all Amyvid readers got at least 5% and up to 14% of diagnoses wrong.”
The common thread between both articles seems to be that Amyvid test may be more useful in determining which applicants should be accepted for drug trials than it would be for general diagnostic tests. The drug, while potentially useful, just may not be the “breakthrough” that people – and Eli Lily – would have liked.
Wang, S.S., (2012, April 9) Alzheimer Diagnosis Possible With Scan. WSJ online. Retrieved from http://online.wsj.com/article/SB10001424052702304587704577332090297872490.html
Herper, M. (2012, April 9) Why Eli Lilly's Alzheimer's Imaging Test Is No Breakthrough. Forbes.com. Retrieved from http://www.forbes.com/sites/matthewherper/2012/04/09/why-eli-lillys-alzheimers-imaging-test-is-no-breakthrough/