GE Healthcare today announced results from four pooled brain biopsy studies, as well as key results from a brain autopsy study, of the investigational PET amyloid imaging agent, [18F]flutemetamol.[i] The data showed that both biopsy and autopsy study images had high sensitivity and specificity, and that strong concordance exists between [18F]flutemetamol PET images and Alzheimer’s disease-associated beta amyloid brain pathology. The data confirm the potential of [18F]flutemetamol as an imaging agent to detect beta amyloid plaque, a pathology associated with Alzheimer’s disease (AD), in living patients.
These data are being presented as part of the Emerging Science Program (formerly known as Late-Breaking Science) at the American Academy of Neurology’s 64th Annual Meeting in New Orleans, April 21 to April 28, 2012, and support an application for regulatory approval of [18F]flutemetamol, which is intended to be filed later this year. [18F]flutemetamol is a GE Healthcare PET imaging agent in development for the detection of beta amyloid.
“Currently, the standard for definitively confirming AD is through detection of pathology, including amyloid plaque in the brain during autopsy,” said David Wolk, MD, Assistant Professor of Neurology in the Cognitive Neurology Division, Department of Neurology, University of Pennsylvania, presenter and lead investigator for the biopsy study. “Because accurate detection of brain amyloid in vivo can help physicians make a more accurate clinical diagnosis and potentially enhance patient management, we were particularly pleased to see that flutemetamol performed in a similar manner in both the autopsy and biopsy studies.”
The study to be presented at AAN pooled analysis from four studies of 49 patients receiving [18F]flutemetamol before or after brain biopsy during shunt placement or intracranial pressure measurement and 68 autopsy subjects to determine the presence of brain amyloid pathology. For patients with biopsy tissue samples, the study found that [18F]flutemetamol detected beta-amyloid with a pooled sensitivity of 93 percent and pooled specificity of 100 percent. In autopsied subjects, [18F]flutemetamol showed the ability to detect beta-amyloid with a sensitivity of 86 percent and specificity of 92 percent. Sensitivity is the percentage of amyloid-positive brains that are correctly identified by [18F]flutemetamol image readers as positive and corresponding to abnormal amyloid pathology. Specificity refers to the percentage of amyloid-negative brains that are correctly identified via [18F]flutemetamol images as negative, corresponding to normal pathology, by image 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 its development. Currently, AD is confirmed by histopathological identification of core features, including beta amyloid plaques, in post-mortem brain samples.[ii] Targeted amyloid imaging agents are being studied to determine their ability to help physicians detect amyloid deposition in living humans.
“We know that AD-related pathological markers such as amyloid plaques may appear decades before clinical symptoms are observed, and these studies show flutemetamol images may prove to be a clinically valuable component of a broader diagnostic workup that neurologists conduct when assessing patients with cognitive impairments who may have AD,” said Jonathan Allis, General Manager, PET, GE Healthcare Medical Diagnostics. “Additionally, the ability to help rule out AD by reliably showing an absence of amyloid deposits in the brain could assist physicians in making appropriate disease management decisions. The results from these studies are encouraging in that they demonstrate the potential of flutemetamol imaging in living patients.”
[18F]Flutemetamol is one component of a broad portfolio of diagnostic solutions that GE Healthcare is currently developing in the Alzheimer’s field. GE Healthcare is taking a comprehensive approach to understanding AD through its ongoing research to uncover the causes, risks and physical effects of the disease. For example, the company is partnering with pharma to identify a biosignature, or biological indicator, that may help physicians diagnose AD before the onset of clinical symptoms.
GE Healthcare offers a broad portfolio of imaging resources, that support accurate visualization of the signs of neurodegenerative diseases via state-of-the-art scanners - including MRI, PET, and CT - that deliver clear visualization of the brain. In addition, an expanding portfolio of imaging agents is being developed to enhance visual evidence of disease and innovative software applications that can aid physicians in image interpretation and determination of disease management. More specifically, our portfolio today includes cyclotrons and chemistry systems to manufacture PET imaging agents, PET and MR scanners to scan patients, and image analysis software to interpret the results.
GE Healthcare has been a key contributor to the Alzheimer’s Disease Neuroimaging Initiative (ADNI) since its inception. GE Healthcare also plays a key role in PredictAD, an EU-funded research project to develop solutions to enable earlier diagnosis of AD, and in the Coalition Against Major Diseases (CAMD).
Additionally, the combination of our different business offerings positions us well to offer an integrated global diagnostics solution to assist the pharmaceutical industry in their development of the next generation of therapies. To that end, we are working with potential partners in the pharmaceutical industry to understand their strategic needs and design solutions, and help provide imaging support for pivotal therapy trials.
[i] Wolk D, Gamez J, Sadowsky C et. al. Brain autopsy and in vivo cortical brain biopsy trials show a strong concordance between [18F]Flutemetamol PET and amyloid-β pathology. Poster presented at: 64th Annual Meeting of the American Academy of Neurology, April 21-28, 2012; New Orleans, LA.
[ii] Dementia: Hope Through Research. National Institute of Neurological Disorders and Stroke website. ninds.nih.gov/. Accessed July 13, 2011.
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