Autopsy Follow-up of Subjects Previously Imaged With Florbetapir F 18 (18F-AV-45) PET in Trial 18F-AV-45-A07

Autopsy Follow-up of Subjects Previously Imaged With Florbetapir F 18 (18F-AV-45) PET in Trial 18F-AV-45-A07

Autopsy Follow-up of Subjects Previously Imaged With Florbetapir F 18 (18F-AV-45) PET in Trial 18F-AV-45-A07

This study is designed to test the relationship between measurements of brain amyloid using florbetapir F 18 PET imaging and true levels of amyloid plaque density as measured by histopathological assessment. The study will address the following specific aims: To expand the number of subjects included in the A07 (NCT00857415) trial correlation analysis (measuring the correlation between the global visual rating of brain amyloid plaque density on an independent blinded read of the florbetapir F 18 PET scan and the cortical amyloid plaque density at autopsy as assessed by histopathology for subjects in the autopsy cohort). To determine the sensitivity and specificity of an independent blinded visual read assessment of the florbetapir F 18 PET scan (Aβ+ or Aβ-) versus the final blinded neuropathological assessment made at autopsy.

No study drug administered in this trial. Study subjects previously dosed with 18F-AV-45 in study 18F-AV-45-A07 (NCT00857415) are followed to autopsy in this extension study.

Sensitivity of florbetapir-PET scan to detect moderate to frequent amyloid plaques. Plaque density was calculated using CERAD (Consortium to Establish a Registry for AD) criteria. Florbetpir-PET scans were read by five independent readers blinded to clinical information using the binary read method (amyloid positive/negative).

Specificity of florbetapir-PET scan to detect moderate to frequent amyloid plaques. Plaque density was calculated using CERAD criteria. Florbetpir-PET scans were read by five independent readers blinded to clinical information using the binary read method (amyloid positive/negative).

Spearman's rank order correlation of the median visual read of the florbetapir-PET image and the amyloid plaque density assessed post-mortem by quantitative immunohistochemistry (IHC) averaged across 6 brain regions (precuneus, parietal cortex, frontal cortex, temporal cortex, posterior cingulate, anterior cingulate). Spearman's rank order correlation ranges from -1 to +1. A value of -1 indicates perfect negative correlation, and a value of +1 indicates a perfect positive correlation.

Sensitivity of florbetapir-PET scan to detect moderate to frequent amyloid plaques. Plaque density was calculated using CERAD criteria. Florbetpir-PET scans were read by five independent readers blinded to clinical information using the binary read method (amyloid positive/negative).

Specificity of florbetapir-PET scan to detect moderate to frequent amyloid plaques. Plaque density was calculated using CERAD criteria. Florbetpir-PET scans were read by five independent readers blinded to clinical information using the binary read method (amyloid positive/negative).

Median sensitivity and specificity for 5 independent readers to detect moderate to frequent amyloid plaques (per CERAD criteria).

Reader results (number of false negatives and number of false positives) for blinded independent readers. There were a total of 39 positive and 20 negative scans based on histopathology at autopsy.

Reader results (number of false negatives and number of false positives) for blinded independent readers. There were a total of 28 positive and 18 negative scans based on histopathology at autopsy.

Inclusion Criteria: Subjects are enrolled in this study if they: Met entrance criteria and were enrolled and imaged in trial 18F-AV-45-A07 (NCT00857415) Gave informed consent for the 18F-AV-45-A07 (NCT00857415) study procedures and brain donation consistent with the legal requirements of the State in which they are enrolled and the State in which they die Consent to participate in the 18F-AV-45-A16 (NCT01447719) extension protocol, if required by the IRB Reconfirm their consent to a research brain autopsy, if required by the IRB.

Clark CM, Pontecorvo MJ, Beach TG, Bedell BJ, Coleman RE, Doraiswamy PM, Fleisher AS, Reiman EM, Sabbagh MN, Sadowsky CH, Schneider JA, Arora A, Carpenter AP, Flitter ML, Joshi AD, Krautkramer MJ, Lu M, Mintun MA, Skovronsky DM; AV-45-A16 Study Group. Cerebral PET with florbetapir compared with neuropathology at autopsy for detection of neuritic amyloid-beta plaques: a prospective cohort study. Lancet Neurol. 2012 Aug;11(8):669-78. doi: 10.1016/S1474-4422(12)70142-4. Epub 2012 Jun 28. Erratum In: Lancet Neurol. 2012 Aug;11(8):658.