Avid Radiopharmaceuticals

About: Avid Radiopharmaceuticals is a based out in . It is known for research contribution in the topics: Alzheimer's disease & Dementia. The organization has 105 authors who have published 196 publications receiving 13410 citations.

Use of Florbetapir-PET for Imaging β-Amyloid Pathology

Abstract: Context The ability to identify and quantify brain β-amyloid could increase the accuracy of a clinical diagnosis of Alzheimer disease. Objective To determine if florbetapir F 18 positron emission tomographic (PET) imaging performed during life accurately predicts the presence of β-amyloid in the brain at autopsy. Design, Setting, and Participants Prospective clinical evaluation conducted February 2009 through March 2010 of florbetapir-PET imaging performed on 35 patients from hospice, long-term care, and community health care facilities near the end of their lives (6 patients to establish the protocol and 29 to validate) compared with immunohistochemistry and silver stain measures of brain β-amyloid after their death used as the reference standard. PET images were also obtained in 74 young individuals (18-50 years) presumed free of brain amyloid to better understand the frequency of a false-positive interpretation of a florbetapir-PET image. Main Outcome Measures Correlation of florbetapir-PET image interpretation (based on the median of 3 nuclear medicine physicians' ratings) and semiautomated quantification of cortical retention with postmortem β-amyloid burden, neuritic amyloid plaque density, and neuropathological diagnosis of Alzheimer disease in the first 35 participants autopsied (out of 152 individuals enrolled in the PET pathological correlation study). Results Florbetapir-PET imaging was performed a mean of 99 days (range, 1-377 days) before death for the 29 individuals in the primary analysis cohort. Fifteen of the 29 individuals (51.7%) met pathological criteria for Alzheimer disease. Both visual interpretation of the florbetapir-PET images and mean quantitative estimates of cortical uptake were correlated with presence and quantity of β-amyloid pathology at autopsy as measured by immunohistochemistry (Bonferroni ρ, 0.78 [95% confidence interval, 0.58-0.89]; P Conclusions Florbetapir-PET imaging was correlated with the presence and density of β-amyloid. These data provide evidence that a molecular imaging procedure can identify β-amyloid pathology in the brains of individuals during life. Additional studies are required to understand the appropriate use of florbetapir-PET imaging in the clinical diagnosis of Alzheimer disease and for the prediction of progression to dementia.

Trial of Solanezumab for Mild Dementia Due to Alzheimer’s Disease

Abstract: Background Alzheimer’s disease is characterized by amyloid-beta (Aβ) plaques and neurofibrillary tangles. The humanized monoclonal antibody solanezumab was designed to increase the clearance from the brain of soluble Aβ, peptides that may lead to toxic effects in the synapses and precede the deposition of fibrillary amyloid. Methods We conducted a double-blind, placebo-controlled, phase 3 trial involving patients with mild dementia due to Alzheimer’s disease, defined as a Mini–Mental State Examination (MMSE) score of 20 to 26 (on a scale from 0 to 30, with higher scores indicating better cognition) and with amyloid deposition shown by means of florbetapir positron-emission tomography or Aβ1-42 measurements in cerebrospinal fluid. Patients were randomly assigned to receive solanezumab at a dose of 400 mg or placebo intravenously every 4 weeks for 76 weeks. The primary outcome was the change from baseline to week 80 in the score on the 14-item cognitive subscale of the Alzheimer’s Disease Assessmen...

Cerebral PET with florbetapir compared with neuropathology at autopsy for detection of neuritic amyloid-β plaques: a prospective cohort study

Abstract: Summary Background Results of previous studies have shown associations between PET imaging of amyloid plaques and amyloid-β pathology measured at autopsy. However, these studies were small and not designed to prospectively measure sensitivity or specificity of amyloid PET imaging against a reference standard. We therefore prospectively compared the sensitivity and specificity of amyloid PET imaging with neuropathology at autopsy. Methods This study was an extension of our previous imaging-to-autopsy study of participants recruited at 22 centres in the USA who had a life expectancy of less than 6 months at enrolment. Participants had autopsy within 2 years of PET imaging with florbetapir ( 18 F). For one of the primary analyses, the interpretation of the florbetapir scans (majority interpretation of five nuclear medicine physicians, who classified each scan as amyloid positive or amyloid negative) was compared with amyloid pathology (assessed according to the Consortium to Establish a Registry for Alzheimer's Disease standards, and classed as amyloid positive for moderate or frequent plaques or amyloid negative for no or sparse plaques); correlation of the image analysis results with amyloid burden was tested as a coprimary endpoint. Correlation, sensitivity, and specificity analyses were also done in the subset of participants who had autopsy within 1 year of imaging as secondary endpoints. The study is registered with ClinicalTrials.gov, number NCT 01447719 (original study NCT 00857415). Findings We included 59 participants (aged 47–103 years; cognitive status ranging from normal to advanced dementia). The sensitivity and specificity of florbetapir PET imaging for detection of moderate to frequent plaques were 92% (36 of 39; 95% CI 78–98) and 100% (20 of 20; 80–100%), respectively, in people who had autopsy within 2 years of PET imaging, and 96% (27 of 28; 80–100%) and 100% (18 of 18; 78–100%), respectively, for those who had autopsy within 1 year. Amyloid assessed semiquantitatively with florbetapir PET was correlated with the post-mortem amyloid burden in the participants who had an autopsy within 2 years (Spearman ρ=0·76; p Interpretation The results of this study validate the binary visual reading method approved in the USA for clinical use with florbetapir and suggest that florbetapir could be used to distinguish individuals with no or sparse amyloid plaques from those with moderate to frequent plaques. Additional research is needed to understand the prognostic implications of moderate to frequent plaque density. Funding Avid Radiopharmaceuticals.

Imaging of amyloid β in Alzheimer's disease with 18F-BAY94-9172, a novel PET tracer: proof of mechanism

Abstract: Summary Background Amyloid-β (Aβ) plaque formation is a hallmark of Alzheimer's disease (AD) and precedes the onset of dementia. Aβ imaging should allow earlier diagnosis, but clinical application is hindered by the short decay half-life of current Aβ-specific ligands. 18 F-BAY94-9172 is an Aβ ligand that, due to the half-life of 18 F, is suitable for clinical use. We thus studied the effectiveness of this ligand in identifying patients with AD. Methods 15 patients with mild AD, 15 healthy elderly controls, and five individuals with frontotemporal lobar degeneration (FTLD) were studied. 18 F-BAY94-9172 binding was quantified by use of the standardised uptake value ratio (SUVR), which was calculated for the neocortex by use of the cerebellum as reference region. SUVR images were visually rated as normal or AD. Findings 18 F-BAY94-9172 binding matched the reported post-mortem distribution of Aβ plaques. All AD patients showed widespread neocortical binding, which was greater in the precuneus/posterior cingulate and frontal cortex than in the lateral temporal and parietal cortex. There was relative sparing of sensorimotor, occipital, and medial temporal cortex. Healthy controls and FTLD patients showed only white-matter binding, although three controls and one FTLD patient had mild uptake in frontal and precuneus cortex. At 90–120 min after injection, higher neocortical SUVR was observed in AD patients (2·0 [SD 0·3]) than in healthy controls (1·3 [SD 0·2]; p Interpretation 18 F-BAY94-9172 PET discriminates between AD and FTLD or healthy controls and might facilitate integration of Aβ imaging into clinical practice.

The Centiloid Project: Standardizing quantitative amyloid plaque estimation by PET

Abstract: Although amyloid imaging with PiB-PET ([C-11]Pittsburgh Compound-B positron emission tomography), and now with F-18-labeled tracers, has produced remarkably consistent qualitative findings across a large number of centers, there has been considerable variability in the exact numbers reported as quantitative outcome measures of tracer retention. In some cases this is as trivial as the choice of units, in some cases it is scanner dependent, and of course, different tracers yield different numbers. Our working group was formed to standardize quantitative amyloid imaging measures by scaling the outcome of each particular analysis method or tracer to a 0 to 100 scale, anchored by young controls (≤45 years) and typical Alzheimer's disease patients. The units of this scale have been named "Centiloids." Basically, we describe a "standard" method of analyzing PiB PET data and then a method for scaling any "nonstandard" method of PiB PET analysis (or any other tracer) to the Centiloid scale.