Imaging agent flutemetamol presented at neurology meeting

Results from 4 pooled brain biopsy studies, as well as results from a brain autopsy study of the investigational PET amyloid imaging agent, [18F]flutemetamol, were presented as part of the Emerging Science Program at the American Academy of Neurology's 64th Annual Meeting in New Orleans in April, 2012. Flutemetamol is a GE Healthcare PET imaging agent currently being developed for the detection of beta amyloid. The study demonstrated a high sensitivity and specificity of both biopsy and autopsy study images. There was also a strong concordance between Alzheimer's disease-associated beta amyloid brain pathology and [18F]flutemetamol PET images. The data confirm that [18F]flutemetamol could be used as a potential imaging agent to detect beta amyloid plaque, a pathology linked to Alzheimer's disease (AD) in living patients. In addition, results from these studies support an application for regulatory approval of [18F]flutemetamol, which is intended to be filed later in 2012. David Wolk, M.D., Assistant Professor of Neurology in the Cognitive Neurology Division, Department of Neurology, University of Pennsylvania, presenter and lead researcher for the biopsy study, explained: "Currently, the standard for definitively confirming AD is through detection of pathology, including amyloid plaque in the brain during autopsy. Because accurate detection of brain amyloid in vivo can help physicians make a more accurate clinical diagnosis and potentially enhance patient management, we are particularly pleased to see that flutemetamol performed in a similar manner in both the autopsy and biopsy studies." The researchers pooled analysis from 4 studies involving 49 patients receiving flutemetamol, either before or after brain biopsy, during shunt placement or intracranial pressure measurement. In addition, the team examined 68 autopsy patients in order to determine the presence of brain amyloid pathology. Results of the study indicated that for patients with biopsy tissue samples, flutemetamol identified beta-amyloid with a pooled specificity of 100% and pooled sensitivity of 93%. Sensitivity is defined as the percentage of amyloid-positive brains correctly identified by flutemetamol image readers as being positive and that correspond to abnormal amyloid pathology, whilst the definition of specificity means the percentage of amyloid-negative brains that are correctly identified by image readers as negative flutemetamol images that correspond to normal pathology. In autopsy patients the team found that flutemetamol demonstrated the ability to identify beta-amyloid with a specificity of 92% and sensitivity of 86%. In autopsied subjects, [18F]flutemetamol showed the ability to detect beta-amyloid with a sensitivity of 86 percent and specificity of 92 percent. Researchers believe that the accumulation of beta amyloid in the brain has an impact on the degeneration of neurons in AD and is one of many pathological characteristics implicated in its development. In post-mortem brain samples, AD is currently verified by histopathological identification of core features, including beta amyloid plaques. Researchers are currently researching targeted amyloid imaging agents in order to determine their ability to assist physicians identify amyloid deposition in living humans. Jonathan Allis, General Manager, PET, GE Healthcare Medical Diagnostics explained: "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. 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." 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 studying AD via its ongoing research in order to identify the causes, risks and physical effects of the disease. For instance, GE Healthcare is collaborating with pharma in order to identify a biosignature, or biological indicator, that may assist physicians diagnose AD prior to the onset of clinical symptoms.