PET Scan Marker May Promise Hope for Earlier Alzheimer’s Detection

February 25, 2011

By Kelli Rush

The results of a Phase II study may offer hope for earlier diagnosis of Alzheimer’s disease. The study, presented in April at the 2010 American Academy of Neurology conference in Toronto, focused on a compound called Flutemetamol that is being developed by GE Healthcare as a marker for Alzheimer-related amyloid plaques.

Dr. Rik Vandenberghe, a professor of neurology at the University Hospital in Leuven, Belgium, is the lead investigator of the Phase II study of Flutemetamol.

When Flutemetamol was introduced in patients showing signs of Alzheimer’s and a control group of healthy adults, the study found that PET image readers were able to reliably differentiate between Alzheimer’s patients and the controls.

The results could have important implications for diagnosis and treatment, says Dr. Rik Vandenberghe, the lead investigator of the trial and a professor of neurology at the University Hospital in Leuven, Belgium. “Although many more questions remain,” he says, “the results are an important step in the process of validating this compound for clinical use.” Flutemetamol may eventually aid in earlier detection of Alzheimer’s, Vandenberghe says.

“At present, Alzheimer’s can be diagnosed only when a patient has already advanced to the dementia stage,” he says, “and there’s already an impact on daily living. One potential use of this agent is to allow us to make a reliable diagnosis at an earlier stage. Of course, that is most useful if it goes hand in hand with more efficacious treatment, applied earlier.”

Phase II Study
The study introduced Flutemetamol in 52 subjects, 27 of whom showed signs of Alzheimer’s while 25 showed no signs. Five image readers independently examined the study subjects’ brain scans and were able to accurately differentiate between the two groups.

The study also found that Flutemetamol binding was easy to replicate within the same subject over time. Subjects were scanned initially, then rescanned one week later. The results were similar, meaning that Flutemetamol might be used reliably in longer-term clinical trials, Vandenberghe says.

Other Markers
In addition, the study found a very high correlation between the effectiveness of Flutemetamol and its parent molecule, 11C Pittsburgh compound B (PiB). PiB can be used to detect Alzheimer’s but has a shorter half-life than Flutemetamol and cannot be transported, limiting its practical use. Flutemetamol, with a longer half-life, “can be produced at one site and be transported to another,” Vandenberghe says.

Phase III Trials
Phase III will examine whether Flutemetamol allows doctors to predict who will develop Alzheimer’s and dementia. It will also examine how well Flutemetamol’s effectiveness correlates with direct measures performed on brain tissue from deceased donors.

Vandenberghe emphasizes the importance of these further, Phase III trials. “At this stage,” he says, “we do not want to make claims about the clinical usefulness of Flutemetamol. This is just one important step in the process, and it entails Phase III as well.”

Source: www.ALZinfo.org. Author: Kelli Rush, Preserving Your Memory: The Magazine of Health and Hope; Summer 2010.


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