There is a striking contrast in media coverage of the FDA advisory committee meeting yesterday on a test for a signature feature of Alzheimer's disease. A The New York Times , cutting Gina Kolata enthusiasm is at least half full:
F.D.A. Sees Promise in Alzheimer's imaging drug
An advisory committee of the Food and Drug Administration unanimously recommended Thursday that the agency approve the first test - a brain scan which can show the characteristics of plates Alzheimer's disease in the brain of a living person. The approval was contingent on radiologists agreeing that the analyzes say and trained doctors how to read the scans.
The article quoted experts Alzheimer enthusing about "a monumental step forward," and "a historic day for our field."
Several other outlets, including CNN Health took more than a glass half empty approach:
FDA on the new Alzheimer's test: No, or at least not yet
a new test to detect or rule out Alzheimer's disease are not quite ready for prime time, an advisory committee of the FDA said Thursday afternoon. The test, a type of PET scan developed by Avid Radiopharmaceuticals, is designed to detect the telltale amyloid accumulations of plaque in the brain which means Alzheimer's disease.
In fact, as reported in Alzforum a detailed analysis of the decision, the committee first voted 13-3 to reject new drug application from Avid, then voted unanimously that they recommend approval if the company can strengthen its argument that the analyzes are read regularly by different doctors. Doing this may require improvements in reading scans protocols and training and education programs for neuroradiologists.
Article Alzforum also noted a point that receives almost no mention elsewhere: the demand for Avid is not seeking permission to use the test to diagnose Alzheimer's disease. Rather, it seeks approval for the use rule the presence of amyloid plaques. If the FDA finally granted approval, presumably some doctors use to "off-label" purposes, such as testing people already suspect they have Alzheimer's disease or people screening with mild memory problems.
The AVID compound is based on a radioactive fluorine isotope (F-18), which is injected before the PET to allow doctors to detect amyloid deposits in the brain. It is one of several F-18 compounds in development for this purpose. The first amyloid imaging method developed there nearly a decade, was based on an isotope of carbon short term, C-11, which limits its use to hospitals with their own cyclotron that could make it on square. The new F-18 compounds could be much more widely used.
An important confirmation that the compound Avid accurately detects the plates comes from a study in this week's issue of The Journal of the American Medical Association which shows good agreement between PET findings and autopsy findings in 35 patients.
But do patients really want to know they have the incipient Alzheimer's disease? It is true that knowledge of a loved one has Alzheimer's disease can help families plan for the bumpy road ahead, and the decision to get out of the disease can help neurologists zero on the right diagnosis. But the lack of disease-modifying treatments for Alzheimer's disease may deter some people from getting tested.
For now, the F-18 PET compounds may be more useful for researchers and clinicians. They are already used in clinical trials and in most government and Neuroimaging Initiative Alzheimer industry-sponsored (profiled in Science ). Many researchers believe that the use of amyloid imaging and other biomarkers may help improve clinical trials by helping to exclude patients with other conditions, for example, and the identification of patients with the disease at an early stage. When treatments eventually become available, they are likely to be most effective when administered early - and demand for Alzheimer's tests should really take off.
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