Being able to correctly diagnosis a patient with Alzheimer’s disease can be difficult, but a new method using PET and an investigational imaging agent developed by GE Healthcare has shown promise to take the uncertainty out of this diagnosis.
Researchers recently concluded a phase two study using the investigational imaging agent flutemetamol. The purpose of the study was to determine the efficacy of flutemetamol in differentiating between patients with clinically probable Alzheimer’s and cognitively intact, healthy volunteers. The primary endpoint was the efficacy of blinded assessments of flutemetamol binding to Beta-amyloid, the major constituent of amyloid plaque, which is a pathological hallmark of AD.
In total, 72 patients were imaged for the study. Of those, 27 had a high probability of amyloid, 20 had mild cognitive impairment, and 25 were healthy. The results were read by five independent readers who were blinded as to the patients’ health status. They found that 25 of the 27 Alzheimer’s patients had elevated flutemetamol uptake, as did one of the 15 healthy volunteers who was over 55. Almost half of the mild cognitively impaired patients had high uptake. Test-retest reliability was very high during a repeat scan taken seven days after the initial examination. The researchers also found that flutemetamol uptake ratios were similar to its analog 11CPIB.
The phase 3 multicenter study has commenced and will include patients who consent to brain biopsy or to post-mortem assays to determine the level of association between imaging detection of amyloid and histopathology findings. A separate study is also underway for patients with mild cognitive impairment who may progress to Alzheimer’s.
The full results of the phase 2 study were published in the September issue of the Annals of Neurology (http://onlinelibrary.wiley.com/doi/10.1002/ana.22068/abstract).
(Source: Press Release and Abstract)