Wednesday, April 11, 2012

New Alzheimer Scan Method Approved by FDA Despite Strong Dissent

The article "Alzheimer Diagnosis Possible With Scan" published in the print edition of the Wall Street Journal Monday April 9

Majia here: When I saw this headline I was rather surprised because injecting radionuclides into brains doesn't sound like a good idea, even for the purposes of diagnosing a terrible disease such as Alzheimers.

Presently there is no treatment for Alzheimers so a diagnosis does not have clinical implications while injecting radionuclides into the brain can cause cancer or perhaps cause a stroke.

When I googled the injection this is what i found:

Letter Urging Rejection of Florbetapir F18 Injection (Amyvid)
February 21, 2011

Janet Woodcock, M.D.
Center for Drug Evaluation and Research
Food and Drug Administration
Department of Health and Human Services
WO51/Room 6133
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002

Dear Dr. Woodcock:

These comments from Public Citizen Health Research Group are being submitted in response to Avid Pharmaceuticals’ New Drug Application (NDA), # 202-008, for florbetapir F18 injection (AmyvidTM), which was considered by the Food and Drug Administration’s (FDA’s) Peripheral and Central Nervous System Drugs Advisory Committee on January 20, 2011.

(1) We strongly oppose FDA approval of Avid Pharmaceuticals’ NDA for florbetapir F18 injection.

(2) Given the significant inter-reader variability that was seen in the single phase 3 clinical trial evaluating the performance of florbetapir positron emission tomographic (PET) imaging, such PET scans would have little clinical utility in the evaluation of patients presenting with cognitive deficits or early dementia and suspected of having Alzheimer’s disease (AD)....   

....In conclusion, study A07 implemented florbetapir-PET in a rigorously controlled setting with well-trained readers, using patient populations at two extremes of the spectra for both age and health. However, despite these optimal conditions, the test yielded disparate results when looking at the analysis of the individual readers. If widely deployed in real-world settings, with more variability in reader training and skill and in the patient population for which florbetapir-PET presumably is intended, the performance of the test will be only substantially worseFor these reasons, FDA, based on current evidence, should not approve florbetapir for the evaluation of patients suspected of having Alzheimer’s disease. It is unlikely that better training and a new study in the more appropriate patient population are realistic hurdles to overcome.


Michael A. Carome, M.D.
Deputy Director

Sidney M. Wolfe, M.D.
Health Research Group

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