Article
作者: Tissot, Cécile ; Foroud, Tatiana ; Singer, Juli ; Masdeu, Joseph C. ; Tate, Victoria ; Chan, Tevy ; Vitali, Paolo ; Stevenson, Jenna ; Pascoal, Tharick A ; Jia, Wan Lu ; Gordon, Brian A ; Mroué, Rayan ; Gray, Danielle ; Lukasewicz Ferreira, Pamela ; Bauer-Negrini, Guilherme ; Povala, Guilherme ; Rocha, Andréia ; Hu, Xiaoyang ; Jagust, William J ; Avdagic, Selma ; Medeiros, Marina S. ; Tudorascu, Dana L ; de Oliveira Franco, Álvaro ; Tuma, Raphael L. ; Fonov, Vladimir ; Leffa, Douglas T. ; Bellaver, Bruna ; Baker, Suzanne ; Tsai, Hsin-Yeh ; Gordon, Brian A. ; Amaral, Livia ; Aguzzoli, Cristiano S. ; Klostranec, Jesse ; Tudorascu, Dana L. ; Provost, Karine ; Fortea, Juan ; Tissot, Cecile ; Rodrigues, Matheus S. ; Cummings, Emerine ; Saha, Pampa ; Baker, Suzanne L. ; Masdeu, Joseph C ; Rahmouni, Nesrine ; Rocha, Andreia ; Lowe, Val ; Lussier, Firoza Z. ; Pascual, Belen ; Ruppert, Emma ; Montembault, Maxime ; Ferreira, Pamela C L ; Lussier, Firoza Z ; Soares, Carolina ; Medeiros, Marina S ; Soleimani-Meigooni, David N ; Cohen, Ann D. ; Rosa-Neto, Pedro ; Soleimani-Meigooni, David N. ; Iturria-Medina, Yasser ; Toga, Arthur W. ; Oh, Hwamee ; Pascoal, Tharick A. ; Oliveira, Markley S.
BACKGROUND:Tau PET imaging has emerged as a critical biomarker for Alzheimer's disease, informing diagnosis, staging, and therapeutic selection. We investigated whether PET tracer selection alters tau detection.
METHODS:We conducted a prospective, multicentre, non-randomised, within-participant comparison of [18F]flortaucipir (Tauvid), currently used in clinical settings in the USA and Europe, and [18F]MK6240, an investigational tau PET tracer. Participants were recruited from eight north American sites and underwent tau PET, amyloid-β (Aβ) PET, and detailed cognitive assessments. Tau PET with both agents was acquired within a 45-day window. Coprimary outcomes were the discriminative accuracy for Alzheimer's disease-related cognitive impairment and the frequency of tau positivity in early medial temporal lobe (MTL) and late neocortical regions. The study is registered with ClinicalTrials.gov, NCT05361382.
FINDINGS:Between March 2, 2022, and Aug 27, 2025, 775 individuals were enrolled, with 682 completing all procedures (373 [55%] female, 309 [45%] male; 38 [6%] aged 19-27 years, 214 [31%] aged 50-65 years, and 430 [63%] aged 65-89 years). 32 (5%) participants identified as Hispanic or Latino. 637 (93%) identified as White, 24 (4%) as Black or African American, 16 (2%) as Asian, and five (1%) as other. In addition, 49 (7%) individuals were identified as being from a rural area. [18F]MK6240 showed greater accuracy than [18F]flortaucipir in distinguishing Alzheimer's disease from non-Alzheimer's disease impairment (area under the curve 0·93, 95% CI 0·89-0·95 vs 0·86, 0·75-0·91; p<0·0001). Among the older adults, tau positivity status was concordant in 560 (87%) for MTL and 603 (94%) for neocortical regions. In cognitively unimpaired participants, [18F]MK6240 identified twice as many MTL-positive cases as [18F]flortaucipir (n=54 [15%] vs n=23 [6%]). Prevalence ratio in Aβ-positive was 2·43 (95% CI 1·50-3·94; p=0·0003), identifying 23 additional cases per 100. Among discordant cases, 75 (89%) were [18F]MK6240-positive only and had higher Aβ burden (p<0·0001), APOEε4 frequency (p<0·0001), and cognitive impairment (p=0·0043) than those negative on both tracers. Neocortical tau positivity was more frequent with [18F]MK6240 than with [18F]flortaucipir in cognitively impaired individuals (80 [28%] vs 46 [16%]). Prevalence ratio in Aβ-positive was 1·74 (95% CI 1·32-2·29; p<0·0001), identifying 15 additional mild cognitive impairment and 21 dementia cases per 100.
INTERPRETATION:Tau PET tracer selection influences the frequency of detection of tau pathology across the ageing and Alzheimer's disease spectrum. Compared with [18F]flortaucipir, [18F]MK6240 identified more individuals with tau pathology in cognitively unimpaired and cognitively impaired individuals, with direct implications for patient stratification in clinical trials and more precise guidance for therapeutic decision-making.
FUNDING:National Institute on Aging.