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Investigational Imaging Agent Detects Beta Amyloid Plaques in Living Alzheimer’s Patients
On September 11, GE Healthcare, based in Waukesha, Wis., announced pooled results from phase III brain autopsy and biopsy studies of the investigational PET amyloid imaging agent [18F]flutemetamol. The results showed a strong concordance between [18F]flutemetamol images and Alzheimer’s disease (AD)-associated beta amyloid brain pathology.
[18F]Flutemetamol is a PET imaging agent that GE Healthcare is developing for the detection of beta amyloid deposits in the brain. The data from the phase III studies confirm the potential application of [18F]flutemetamol as an imaging agent to detect beta amyloid plaques.
The findings were presented at the 16th Congress of the European Federation of Neurological Societies (EFNS) in Stockholm, Sweden, and provide support for an application for regulatory approval of [18F]flutemetamol, which the company plans to file in the U.S. later this year.
The clinical development program included 180 end-of-life subjects (69 of whom were followed to autopsy) and 49 subjects with suspected normal-pressure hydrocephalus (NPH) — a progressive condition associated with dementia, gait abnormalities, and urinary incontinence — who underwent in vivo cortical biopsy. All participants received [18F]flutemetamol injection. Beta amyloid was evaluated using Bielschowsky silver stain and/or the beta amyloid peptide specific antibody 4G8. The PET images were then read by trained physicians, who identified the images as normal or abnormal.
[18F]flutemetamol detected beta amyloid with a median sensitivity ranging from 75% to 100% and with a specificity ranging from 99% to 100% among living patients in the biopsy studies. A similar range was observed in autopsied subjects. Further, the visual assessment of all images showed a high level of agreement among readers.
The accumulation of beta amyloid in the brain is believed to play a role in the degeneration of neurons in AD and is one of several pathological characteristics implicated in the development of the disease. AD is currently confirmed by histopathological identification of core features, including beta amyloid plaques, in post-mortem brain samples. Targeted amyloid imaging agents are being studied to determine their ability to help physicians detect amyloid deposition in living patients.
For more information, visit the GE Healthcare Web site.