CROSS-SECTIONAL AND LONGITUDINAL COMPARISON OF TAU IMAGING WITH 18F-MK6240 AND 18F-FLORTAUCIPIR IN POPULATIONS MATCHED FOR AGE, MMSE AND BRAIN BETA-AMYLOID BURDEN
P. Bourgeat, N. Krishnadas, V. Doré, R. Mulligan, R. Tyrrell, S. Bozinovski, K. Huang, J. Fripp, V.L. Villemagne, C.C. Rowe, for the Alzheimer’s Disease Neuroimaging Initiative* and the AIBL research group
J Prev Alz Dis 2023;2(10):251-258
Objectives: Longitudinal tau quantification may provide a useful marker of drug efficacy in clinical trials. Different tau PET tracers may have different sensitivity to longitudinal changes, but without a head-to-head dataset or a carefully designed case-matching procedure, comparing results in different cohorts can be biased. In this study, we compared the tau PET tracers, 18F-MK6240 and 18F-flortaucipir (FTP), both cross-sectionally and longitudinally by case-matching subjects in the AIBL and ADNI longitudinal cohort studies.
Methods: A subset of 113 participants from AIBL and 113 from ADNI imaged using 18F-MK6240 and 18F-FTP respectively, with baseline and follow-up, were matched based on baseline clinical diagnosis, MMSE, age and amyloid (Aβ) PET centiloid value. Subjects were grouped as 64 Aβ- cognitively unimpaired (CU), 22 Aβ+ CU, 14 Aβ+ mild cognitive impairment (MCI) and 13 Aβ+ Alzheimer’s disease (AD). Tracer retention was measured in the mesial, temporoparietal, rest of the cortex, and a meta-temporal region composed of entorhinal, inferior/middle temporal, fusiform, parahippocampus and amygdala. T-tests were employed to assess group separation at baseline using SUVR Z-scores and longitudinally using SUVR%/Yr.
Results: Both tracers detected statistically significant differences at baseline in most regions between all clinical groups. Only 18F-MK6240 showed statistically significant higher rate of SUVR increase in Aβ+ CU compared to Aβ- CU in the mesial, meta-temporal and temporoparietal regions.
Conclusion: 18F-MK6240 appears to be a more sensitive tracer for change in tau level at the preclinical stage of AD.
P. Bourgeat ; N. Krishnadas ; V. Doré ; R. Mulligan ; R. Tyrrell ; S. Bozinovski ; K. Huang ; J. Fripp ; V.L. Villemagne ; C.C. Rowe ; for the Alzheimer’s Disease Neuroimaging Initiative and the AIBL research group ; (2023): Cross-Sectional and Longitudinal Comparison of Tau Imaging with 18F-MK6240 and 18F-Flortaucipir in Populations Matched for Age, MMSE and Brain Beta-Amyloid Burden. The Journal of Prevention of Alzheimer’s Disease (JPAD). http://dx.doi.org/10.14283/jpad.2023.17