Comparison of PET Amyloid Imaging in Japanese and Western Subjects

This was a Phase 2, multicenter study to assess the extent and patterns of \[18F\] flutemetamol uptake in the brains of 3 groups of Japanese subjects: HV, aMCI, and pAD, and to assess the reproducibility of brain uptake and of image interpretation. The 3 comparison groups (HV, aMCI, and pAD) were defined by the subjects' main clinical diagnoses at study entry. Subjects underwent diagnostic quality anatomic brain magnetic resonance imaging (MRI), followed by open-label intravenous (i.v) administration of Flutemetamol F 18 Injection and PET imaging of the brain. Blinded visual image reads were performed by 10 independent board-certified readers (5 Japanese and 5 non-Japanese) with nuclear medicine image interpretation experience. The blinded visual assessments were compared with the subject's clinical diagnoses, and the agreement between the image interpretations made by the 2 groups of readers (Japanese and non-Japanese) was determined. Blinded visual assessments were also compared to quantitative image assessments (standardized uptake value ratio \[SUVRs\]). Inter-reader and intra-reader agreement was also assessed. Test-retest variability was evaluated following a second administration of Flutemetamol F 18 Injection given to a subset (N=5) of pAD subjects between 1 and 4 weeks after their first administration of Flutemetamol F 18 Injection.