Browsing by Author "Brooks, William S."
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Item A trial of gantenerumab or solanezumab in dominantly inherited Alzheimer's disease(Springer Nature, 2021) Salloway, Stephen; Farlow, Martin; McDade, Eric; Clifford, David B.; Wang, Guoqiao; Llibre-Guerra, Jorge J.; Hitchcock, Janice M.; Mills, Susan L.; Santacruz, Anna M.; Aschenbrenner, Andrew J.; Hassenstab, Jason; Benzinger, Tammie L.S.; Gordon, Brian A.; Fagan, Anne M.; Coalier, Kelley A.; Cruchaga, Carlos; Goate, Alison A.; Perrin, Richard J.; Xiong, Chengjie; Li, Yan; Morris, John C.; Snider, B. Joy; Mummery, Catherine; Surti, G. Mustafa; Hannequin, Didier; Wallon, David; Berman, Sarah B.; Lah, James J.; Jimenez-Velazquez, Ivonne Z.; Roberson, Erik D.; van Dyck, Christopher H.; Honig, Lawrence S.; Sánchez-Valle, Raquel; Brooks, William S.; Gauthier, Serge; Galasko, Douglas R.; Masters, Colin L.; Brosch, Jared R.; Hsiung, Ging-Yuek Robin; Jayadev, Suman; Formaglio, Maité; Masellis, Mario; Clarnette, Roger; Pariente, Jérémie; Dubois, Bruno; Pasquier, Florence; Jack, Clifford R., Jr.; Koeppe, Robert; Snyder, Peter J.; Aisen, Paul S.; Thomas, Ronald G.; Berry, Scott M.; Wendelberger, Barbara A.; Andersen, Scott W.; Holdridge, Karen C.; Mintun, Mark A.; Yaari, Roy; Sims, John R.; Baudler, Monika; Delmar, Paul; Doody, Rachelle S.; Fontoura, Paulo; Giacobino, Caroline; Kerchner, Geoffrey A.; Bateman, Randall J.; Dominantly Inherited Alzheimer Network–Trials Unit; Neurology, School of MedicineDominantly inherited Alzheimer's disease (DIAD) causes predictable biological changes decades before the onset of clinical symptoms, enabling testing of interventions in the asymptomatic and symptomatic stages to delay or slow disease progression. We conducted a randomized, placebo-controlled, multi-arm trial of gantenerumab or solanezumab in participants with DIAD across asymptomatic and symptomatic disease stages. Mutation carriers were assigned 3:1 to either drug or placebo and received treatment for 4-7 years. The primary outcome was a cognitive end point; secondary outcomes included clinical, cognitive, imaging and fluid biomarker measures. Fifty-two participants carrying a mutation were assigned to receive gantenerumab, 52 solanezumab and 40 placebo. Both drugs engaged their Aβ targets but neither demonstrated a beneficial effect on cognitive measures compared to controls. The solanezumab-treated group showed a greater cognitive decline on some measures and did not show benefits on downstream biomarkers. Gantenerumab significantly reduced amyloid plaques, cerebrospinal fluid total tau, and phospho-tau181 and attenuated increases of neurofilament light chain. Amyloid-related imaging abnormalities edema was observed in 19.2% (3 out of 11 were mildly symptomatic) of the gantenerumab group, 2.5% of the placebo group and 0% of the solanezumab group. Gantenerumab and solanezumab did not slow cognitive decline in symptomatic DIAD. The asymptomatic groups showed no cognitive decline; symptomatic participants had declined before reaching the target doses.Item Amyloid-Related Imaging Abnormalities in the DIAN-TU-001 Trial of Gantenerumab and Solanezumab: Lessons from a Trial in Dominantly Inherited Alzheimer Disease(Wiley, 2022) Joseph-Mathurin, Nelly; Llibre-Guerra, Jorge J.; Li, Yan; McCullough, Austin A.; Hofmann, Carsten; Wojtowicz, Jakub; Park, Ethan; Wang, Guoqiao; Preboske, Gregory M.; Wang, Qing; Gordon, Brian A.; Chen, Charles D.; Flores, Shaney; Aggarwal, Neelum T.; Berman, Sarah B.; Bird, Thomas D.; Black, Sandra E.; Borowski, Bret; Brooks, William S.; Chhatwal, Jasmeer P.; Clarnette, Roger; Cruchaga, Carlos; Fagan, Anne M.; Farlow, Martin; Fox, Nick C.; Gauthier, Serge; Hassenstab, Jason; Hobbs, Diana A.; Holdridge, Karen C.; Honig, Lawrence S.; Hornbeck, Russ C.; Hsiung, Ging-Yuek R.; Jack, Clifford R., Jr.; Jimenez-Velazquez, Ivonne Z.; Jucker, Mathias; Klein, Gregory; Levin, Johannes; Mancini, Michele; Masellis, Mario; McKay, Nicole S.; Mummery, Catherine J.; Ringman, John M.; Shimada, Hiroyuki; Snider, B. Joy; Suzuki, Kazushi; Wallon, David; Xiong, Chengjie; Yaari, Roy; McDade, Eric; Perrin, Richard J.; Bateman, Randall J.; Salloway, Stephen P.; Benzinger, Tammie L. S.; Clifford, David B.; Dominantly Inherited Alzheimer Network Trials Unit; Neurology, School of MedicineObjective: To determine the characteristics of participants with amyloid-related imaging abnormalities (ARIA) in a trial of gantenerumab or solanezumab in dominantly inherited Alzheimer disease (DIAD). Methods: 142 DIAD mutation carriers received either gantenerumab SC (n = 52), solanezumab IV (n = 50), or placebo (n = 40). Participants underwent assessments with the Clinical Dementia Rating® (CDR®), neuropsychological testing, CSF biomarkers, β-amyloid positron emission tomography (PET), and magnetic resonance imaging (MRI) to monitor ARIA. Cross-sectional and longitudinal analyses evaluated potential ARIA-related risk factors. Results: Eleven participants developed ARIA-E, including 3 with mild symptoms. No ARIA-E was reported under solanezumab while gantenerumab was associated with ARIA-E compared to placebo (odds ratio [OR] = 9.1, confidence interval [CI][1.2, 412.3]; p = 0.021). Under gantenerumab, APOE-ɛ4 carriers were more likely to develop ARIA-E (OR = 5.0, CI[1.0, 30.4]; p = 0.055), as were individuals with microhemorrhage at baseline (OR = 13.7, CI[1.2, 163.2]; p = 0.039). No ARIA-E was observed at the initial 225 mg/month gantenerumab dose, and most cases were observed at doses >675 mg. At first ARIA-E occurrence, all ARIA-E participants were amyloid-PET+, 60% were CDR >0, 60% were past their estimated year to symptom onset, and 60% had also incident ARIA-H. Most ARIA-E radiologically resolved after dose adjustment and developing ARIA-E did not significantly increase odds of trial discontinuation. ARIA-E was more frequently observed in the occipital lobe (90%). ARIA-E severity was associated with age at time of ARIA-E. Interpretation: In DIAD, solanezumab was not associated with ARIA. Gantenerumab dose over 225 mg increased ARIA-E risk, with additional risk for individuals APOE-ɛ4(+) or with microhemorrhage. ARIA-E was reversible on MRI in most cases, generally asymptomatic, without additional risk for trial discontinuation.Item Avoid or Embrace? Practice Effects in Alzheimer’s Disease Prevention Trials(Frontiers Media, 2022-06-16) Aschenbrenner, Andrew J.; Hassenstab, Jason; Wang, Guoqiao; Li, Yan; Xiong, Chengjie; McDade, Eric; Clifford, David B.; Salloway, Stephen; Farlow, Martin; Yaari, Roy; Cheng, Eden Y. J.; Holdridge, Karen C.; Mummery, Catherine J.; Masters, Colin L.; Hsiung, Ging-Yuek; Surti, Ghulam; Day, Gregory S.; Weintraub, Sandra; Honig, Lawrence S.; Galvin, James E.; Ringman, John M.; Brooks, William S.; Fox, Nick C.; Snyder, Peter J.; Suzuki, Kazushi; Shimada, Hiroyuki; Gräber, Susanne; Bateman, Randall J.; Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU); Neurology, School of MedicineDemonstrating a slowing in the rate of cognitive decline is a common outcome measure in clinical trials in Alzheimer's disease (AD). Selection of cognitive endpoints typically includes modeling candidate outcome measures in the many, richly phenotyped observational cohort studies available. An important part of choosing cognitive endpoints is a consideration of improvements in performance due to repeated cognitive testing (termed "practice effects"). As primary and secondary AD prevention trials are comprised predominantly of cognitively unimpaired participants, practice effects may be substantial and may have considerable impact on detecting cognitive change. The extent to which practice effects in AD prevention trials are similar to those from observational studies and how these potential differences impact trials is unknown. In the current study, we analyzed data from the recently completed DIAN-TU-001 clinical trial (TU) and the associated DIAN-Observational (OBS) study. Results indicated that asymptomatic mutation carriers in the TU exhibited persistent practice effects on several key outcomes spanning the entire trial duration. Critically, these practice related improvements were larger on certain tests in the TU relative to matched participants from the OBS study. Our results suggest that the magnitude of practice effects may not be captured by modeling potential endpoints in observational studies where assessments are typically less frequent and drug expectancy effects are absent. Using alternate instrument forms (represented in our study by computerized tasks) may partly mitigate practice effects in clinical trials but incorporating practice effects as outcomes may also be viable. Thus, investigators must carefully consider practice effects (either by minimizing them or modeling them directly) when designing cognitive endpoint AD prevention trials by utilizing trial data with similar assessment frequencies.Item Comparative neurofilament light chain trajectories in CSF and plasma in autosomal dominant Alzheimer's disease(Springer Nature, 2024-11-18) Hofmann, Anna; Häsler, Lisa M.; Lambert, Marius; Kaeser, Stephan A.; Gräber-Sultan, Susanne; Obermüller, Ulrike; Kuder-Buletta, Elke; la Fougere, Christian; Laske, Christoph; Vöglein, Jonathan; Levin, Johannes; Fox, Nick C.; Ryan, Natalie S.; Zetterberg, Henrik; Llibre-Guerra, Jorge J.; Perrin, Richard J.; Ibanez, Laura; Schofield, Peter R.; Brooks, William S.; Day, Gregory S.; Farlow, Martin R.; Allegri, Ricardo F.; Mendez, Patricio Chrem; Ikeuchi, Takeshi; Kasuga, Kensaku; Lee, Jae-Hong; Roh, Jee Hoon; Mori, Hiroshi; Lopera, Francisco; Bateman, Randall J.; McDade, Eric; Gordon, Brian A.; Chhatwal, Jasmeer P.; Jucker, Mathias; Schultz, Stephanie A.; Dominantly Inherited Alzheimer Network; Pathology and Laboratory Medicine, School of MedicineDisease-modifying therapies for Alzheimer's disease (AD) are likely to be most beneficial when initiated in the presymptomatic phase. To track the benefit of such interventions, fluid biomarkers are of great importance, with neurofilament light chain protein (NfL) showing promise for monitoring neurodegeneration and predicting cognitive outcomes. Here, we update and complement previous findings from the Dominantly Inherited Alzheimer Network Observational Study by using matched cross-sectional and longitudinal cerebrospinal fluid (CSF) and plasma samples from 567 individuals, allowing timely comparative analyses of CSF and blood trajectories across the entire disease spectrum. CSF and plasma trajectories were similar at presymptomatic stages, discriminating mutation carriers from non-carrier controls 10-20 years before the estimated onset of clinical symptoms, depending on the statistical model used. However, after symptom onset the rate of change in CSF NfL continued to increase steadily, whereas the rate of change in plasma NfL leveled off. Both plasma and CSF NfL changes were associated with grey-matter atrophy, but not with Aβ-PET changes, supporting a temporal decoupling of Aβ deposition and neurodegeneration. These observations support NfL in both CSF and blood as an early marker of neurodegeneration but suggest that NfL measured in the CSF may be better suited for monitoring clinical trial outcomes in symptomatic AD patients.Item Comparing cortical signatures of atrophy between late-onset and autosomal dominant Alzheimer disease(Elsevier, 2020) Dincer, Aylin; Gordon, Brian A.; Hari-Raj, Amrita; Keefe, Sarah J.; Flores, Shaney; McKay, Nicole S.; Paulick, Angela M.; Shady Lewis, Kristine E.; Feldman, Rebecca L.; Hornbeck, Russ C.; Allegri, Ricardo; Ances, Beau M.; Berman, Sarah B.; Brickman, Adam M.; Brooks, William S.; Cash, David M.; Chhatwal, Jasmeer P.; Farlow, Martin R.; la Fougère, Christian; Fox, Nick C.; Fulham, Michael J.; Jack, Clifford R., Jr.; Joseph-Mathurin, Nelly; Karch, Celeste M.; Lee, Athene; Levin, Johannes; Masters, Colin L.; McDade, Eric M.; Oh, Hwamee; Perrin, Richard J.; Raji, Cyrus; Salloway, Stephen P.; Schofield, Peter R.; Su, Yi; Villemagne, Victor L.; Wang, Qing; Weiner, Michael W.; Xiong, Chengjie; Yakushev, Igor; Morris, John C.; Bateman, Randall J.; Benzinger, Tammie L.S.; Neurology, School of MedicineDefining a signature of cortical regions of interest preferentially affected by Alzheimer disease (AD) pathology may offer improved sensitivity to early AD compared to hippocampal volume or mesial temporal lobe alone. Since late-onset Alzheimer disease (LOAD) participants tend to have age-related comorbidities, the younger-onset age in autosomal dominant AD (ADAD) may provide a more idealized model of cortical thinning in AD. To test this, the goals of this study were to compare the degree of overlap between the ADAD and LOAD cortical thinning maps and to evaluate the ability of the ADAD cortical signature regions to predict early pathological changes in cognitively normal individuals. We defined and analyzed the LOAD cortical maps of cortical thickness in 588 participants from the Knight Alzheimer Disease Research Center (Knight ADRC) and the ADAD cortical maps in 269 participants from the Dominantly Inherited Alzheimer Network (DIAN) observational study. Both cohorts were divided into three groups: cognitively normal controls (nADRC = 381; nDIAN = 145), preclinical (nADRC = 153; nDIAN = 76), and cognitively impaired (nADRC = 54; nDIAN = 48). Both cohorts underwent clinical assessments, 3T MRI, and amyloid PET imaging with either 11C-Pittsburgh compound B or 18F-florbetapir. To generate cortical signature maps of cortical thickness, we performed a vertex-wise analysis between the cognitively normal controls and impaired groups within each cohort using six increasingly conservative statistical thresholds to determine significance. The optimal cortical map among the six statistical thresholds was determined from a receiver operating characteristic analysis testing the performance of each map in discriminating between the cognitively normal controls and preclinical groups. We then performed within-cohort and cross-cohort (e.g. ADAD maps evaluated in the Knight ADRC cohort) analyses to examine the sensitivity of the optimal cortical signature maps to the amyloid levels using only the cognitively normal individuals (cognitively normal controls and preclinical groups) in comparison to hippocampal volume. We found the optimal cortical signature maps were sensitive to early increases in amyloid for the asymptomatic individuals within their respective cohorts and were significant beyond the inclusion of hippocampus volume, but the cortical signature maps performed poorly when analyzing across cohorts. These results suggest the cortical signature maps are a useful MRI biomarker of early AD-related neurodegeneration in preclinical individuals and the pattern of decline differs between LOAD and ADAD.Item Comparison of Pittsburgh compound B and florbetapir in cross-sectional and longitudinal studies(Elsevier, 2019-02-22) Su, Yi; Flores, Shaney; Wang, Guoqiao; Hornbeck, Russ C.; Speidel, Benjamin; Joseph-Mathurin, Nelly; Vlassenko, Andrei G.; Gordon, Brian A.; Koeppe, Robert A.; Klunk, William E.; Clifford, R. Jack, Jr.; Farlow, Martin R.; Salloway, Stephen; Snider, Barbara J.; Berman, Sarah B.; Roberson, Erik D.; Broschi, Jared; Jimenez-Velazques, Ivonne; van Dyck, Christopher H.; Galasko, Douglas; Yuan, Shauna H.; Jayadev, Suman; Honig, Lawrence S.; Gauthier, Serge; Hsiung, Ging-Yuek R.; Masellis, Mario; Brooks, William S.; Fulham, Michael; Clarnette, Roger; Masters, Colin L.; Wallon, David; Hannequin, Didier; Dubois, Bruno; Pariente, Jeremie; Sanchez-Valle, Raquel; Mummery, Catherine; Ringman, John M.; Bottlaender, Michel; Klein, Gregory; Milosavljevic-Ristic, Smiljana; McDade, Eric; Xiong, Chengjie; Morris, John C.; Bateman, Randall J.; Benzinger, Tammie L.S.; Neurology, School of MedicineIntroduction: Quantitative in vivo measurement of brain amyloid burden is important for both research and clinical purposes. However, the existence of multiple imaging tracers presents challenges to the interpretation of such measurements. This study presents a direct comparison of Pittsburgh compound B-based and florbetapir-based amyloid imaging in the same participants from two independent cohorts using a crossover design. Methods: Pittsburgh compound B and florbetapir amyloid PET imaging data from three different cohorts were analyzed using previously established pipelines to obtain global amyloid burden measurements. These measurements were converted to the Centiloid scale to allow fair comparison between the two tracers. The mean and inter-individual variability of the two tracers were compared using multivariate linear models both cross-sectionally and longitudinally. Results: Global amyloid burden measured using the two tracers were strongly correlated in both cohorts. However, higher variability was observed when florbetapir was used as the imaging tracer. The variability may be partially caused by white matter signal as partial volume correction reduces the variability and improves the correlations between the two tracers. Amyloid burden measured using both tracers was found to be in association with clinical and psychometric measurements. Longitudinal comparison of the two tracers was also performed in similar but separate cohorts whose baseline amyloid load was considered elevated (i.e., amyloid positive). No significant difference was detected in the average annualized rate of change measurements made with these two tracers. Discussion: Although the amyloid burden measurements were quite similar using these two tracers as expected, difference was observable even after conversion into the Centiloid scale. Further investigation is warranted to identify optimal strategies to harmonize amyloid imaging data acquired using different tracers.Item Downstream Biomarker Effects of Gantenerumab or Solanezumab in Dominantly Inherited Alzheimer Disease: The DIAN-TU-001 Randomized Clinical Trial(American Medical Association, 2024) Wagemann, Olivia; Liu, Haiyan; Wang, Guoqiao; Shi, Xinyu; Bittner, Tobias; Scelsi, Marzia A.; Farlow, Martin R.; Clifford, David B.; Supnet-Bell, Charlene; Santacruz, Anna M.; Aschenbrenner, Andrew J.; Hassenstab, Jason J.; Benzinger, Tammie L. S.; Gordon, Brian A.; Coalier, Kelley A.; Cruchaga, Carlos; Ibanez, Laura; Perrin, Richard J.; Xiong, Chengjie; Li, Yan; Morris, John C.; Lah, James J.; Berman, Sarah B.; Roberson, Erik D.; van Dyck, Christopher H.; Galasko, Douglas; Gauthier, Serge; Hsiung, Ging-Yuek R.; Brooks, William S.; Pariente, Jérémie; Mummery, Catherine J.; Day, Gregory S.; Ringman, John M.; Mendez, Patricio Chrem; St. George-Hyslop, Peter; Fox, Nick C.; Suzuki, Kazushi; Okhravi, Hamid R.; Chhatwal, Jasmeer; Levin, Johannes; Jucker, Mathias; Sims, John R.; Holdridge, Karen C.; Proctor, Nicholas K.; Yaari, Roy; Andersen, Scott W.; Mancini, Michele; Llibre-Guerra, Jorge; Bateman, Randall J.; McDade, Eric; Dominantly Inherited Alzheimer Network–Trials Unit; Neurology, School of MedicineImportance: Effects of antiamyloid agents, targeting either fibrillar or soluble monomeric amyloid peptides, on downstream biomarkers in cerebrospinal fluid (CSF) and plasma are largely unknown in dominantly inherited Alzheimer disease (DIAD). Objective: To investigate longitudinal biomarker changes of synaptic dysfunction, neuroinflammation, and neurodegeneration in individuals with DIAD who are receiving antiamyloid treatment. Design, setting, and participants: From 2012 to 2019, the Dominantly Inherited Alzheimer Network Trial Unit (DIAN-TU-001) study, a double-blind, placebo-controlled, randomized clinical trial, investigated gantenerumab and solanezumab in DIAD. Carriers of gene variants were assigned 3:1 to either drug or placebo. The present analysis was conducted from April to June 2023. DIAN-TU-001 spans 25 study sites in 7 countries. Biofluids and neuroimaging from carriers of DIAD gene variants in the gantenerumab, solanezumab, and placebo groups were analyzed. Interventions: In 2016, initial dosing of gantenerumab, 225 mg (subcutaneously every 4 weeks) was increased every 8 weeks up to 1200 mg. In 2017, initial dosing of solanezumab, 400 mg (intravenously every 4 weeks) was increased up to 1600 mg every 4 weeks. Main outcomes and measures: Longitudinal changes in CSF levels of neurogranin, soluble triggering receptor expressed on myeloid cells 2 (sTREM2), chitinase 3-like 1 protein (YKL-40), glial fibrillary acidic protein (GFAP), neurofilament light protein (NfL), and plasma levels of GFAP and NfL. Results: Of 236 eligible participants screened, 43 were excluded. A total of 142 participants (mean [SD] age, 44 [10] years; 72 female [51%]) were included in the study (gantenerumab, 52 [37%]; solanezumab, 50 [35%]; placebo, 40 [28%]). Relative to placebo, gantenerumab significantly reduced CSF neurogranin level at year 4 (mean [SD] β = -242.43 [48.04] pg/mL; P < .001); reduced plasma GFAP level at year 1 (mean [SD] β = -0.02 [0.01] ng/mL; P = .02), year 2 (mean [SD] β = -0.03 [0.01] ng/mL; P = .002), and year 4 (mean [SD] β = -0.06 [0.02] ng/mL; P < .001); and increased CSF sTREM2 level at year 2 (mean [SD] β = 1.12 [0.43] ng/mL; P = .01) and year 4 (mean [SD] β = 1.06 [0.52] ng/mL; P = .04). Solanezumab significantly increased CSF NfL (log) at year 4 (mean [SD] β = 0.14 [0.06]; P = .02). Correlation analysis for rates of change found stronger correlations between CSF markers and fluid markers with Pittsburgh compound B positron emission tomography for solanezumab and placebo. Conclusions and relevance: This randomized clinical trial supports the importance of fibrillar amyloid reduction in multiple AD-related processes of neuroinflammation and neurodegeneration in CSF and plasma in DIAD. Additional studies of antiaggregated amyloid therapies in sporadic AD and DIAD are needed to determine the utility of nonamyloid biomarkers in determining disease modification.Item Higher systolic blood pressure in early-mid adulthood is associated with poorer cognitive performance in those with a dominantly inherited Alzheimer’s Disease mutation but not in non-carriers. Results from the DIAN study(Wiley, 2023) Xu, Ying; Aung, Htein Linn; Bateman, Randall J.; Brooks, William S.; Chhatwal, Jasmeer; Day, Gregory S.; Fagan, Anne M.; Farlow, Martin R.; Gordon, Brian; Kehoe, Patrick G.; Levin, Johannes; Mori, Hiroshi; Morris, John C.; Wharton, Whitney; Humburg, Peter; Schofield, Peter R.; Peters, Ruth; Dominantly Inherited Alzheimer Network (DIAN); Neurology, School of MedicineBackground: The Dominantly Inherited Alzheimer Network (DIAN) is a longitudinal observational study that collects data on cognition, blood pressure (BP), and other variables from autosomal-dominant Alzheimer's disease mutation carriers (MCs) and non-carrier (NC) family members in early to mid-adulthood, providing a unique opportunity to evaluate BP and cognition relationships in these populations. Method: We examined cross-sectional and longitudinal relationships between systolic and diastolic BP and cognition in DIAN MC and NC. Results: Data were available from 528 participants, who had a mean age of 38 (SD = 11) and were 42% male and 61% MCs, at a median follow-up of 2 years. Linear-multilevel models found only cross-sectional associations in the MC group between higher systolic BP and poorer performance on language (β = -0.181 [-0.318, -0.044]), episodic memory (-0.212 [-0.375, -0.049]), and a composite cognitive measure (-0.146 [-0.276, -0.015]). In NCs, the relationship was cross-sectional only and present for language alone. Discussion: Higher systolic BP was cross-sectionally but not longitudinally associated with poorer cognition, particularly in MCs. BP may influence cognition gradually, but further longitudinal research is needed.Item Longitudinal Accumulation of Cerebral Microhemorrhages in Dominantly Inherited Alzheimer Disease(American Academy of Neurology, 2021-03-23) Joseph-Mathurin, Nelly; Wang, Guoqiao; Kantarci, Kejal; Jack, Clifford R., Jr.; McDade, Eric; Hassenstab, Jason; Blazey, Tyler M.; Gordon, Brian A.; Su, Yi; Chen, Gengsheng; Massoumzadeh, Parinaz; Hornbeck, Russ C.; Allegri, Ricardo F.; Ances, Beau M.; Berman, Sarah B.; Brickman, Adam M.; Brooks, William S.; Cash, David M.; Chhatwal, Jasmeer P.; Chui, Helena C.; Correia, Stephen; Cruchaga, Carlos; Farlow, Martin R.; Fox, Nick C.; Fulham, Michael; Ghetti, Bernardino; Graff-Radford, Neill R.; Johnson, Keith A.; Karch, Celeste M.; Laske, Christoph; Lee, Athene K.W.; Levin, Johannes; Masters, Colin L.; Noble, James M.; O’Connor, Antoinette; Perrin, Richard J.; Preboske, Gregory M.; Ringman, John M.; Rowe, Christopher C.; Salloway, Stephen; Saykin, Andrew J.; Schofield, Peter R.; Shimada, Hiroyuki; Shoji, Mikio; Suzuki, Kazushi; Villemagne, Victor L.; Xiong, Chengjie; Yakushev, Igor; Morris, John C.; Bateman, Randall J.; Benzinger, Tammie L.S.; Pathology and Laboratory Medicine, School of MedicineObjective: To investigate the inherent clinical risks associated with the presence of cerebral microhemorrhages (CMHs) or cerebral microbleeds and characterize individuals at high risk for developing hemorrhagic amyloid-related imaging abnormality (ARIA-H), we longitudinally evaluated families with dominantly inherited Alzheimer disease (DIAD). Methods: Mutation carriers (n = 310) and noncarriers (n = 201) underwent neuroimaging, including gradient echo MRI sequences to detect CMHs, and neuropsychological and clinical assessments. Cross-sectional and longitudinal analyses evaluated relationships between CMHs and neuroimaging and clinical markers of disease. Results: Three percent of noncarriers and 8% of carriers developed CMHs primarily located in lobar areas. Carriers with CMHs were older, had higher diastolic blood pressure and Hachinski ischemic scores, and more clinical, cognitive, and motor impairments than those without CMHs. APOE ε4 status was not associated with the prevalence or incidence of CMHs. Prevalent or incident CMHs predicted faster change in Clinical Dementia Rating although not composite cognitive measure, cortical thickness, hippocampal volume, or white matter lesions. Critically, the presence of 2 or more CMHs was associated with a significant risk for development of additional CMHs over time (8.95 ± 10.04 per year). Conclusion: Our study highlights factors associated with the development of CMHs in individuals with DIAD. CMHs are a part of the underlying disease process in DIAD and are significantly associated with dementia. This highlights that in participants in treatment trials exposed to drugs, which carry the risk of ARIA-H as a complication, it may be challenging to separate natural incidence of CMHs from drug-related CMHs.Item Longitudinal head-to-head comparison of 11C-PiB and 18F-florbetapir PET in a Phase 2/3 clinical trial of anti-amyloid-β monoclonal antibodies in dominantly inherited Alzheimer disease(Springer, 2023) Chen, Charles D.; McCullough, Austin; Gordon, Brian; Joseph-Mathurin, Nelly; Flores, Shaney; McKay, Nicole S.; Hobbs, Diana A.; Hornbeck, Russ; Fagan, Anne M.; Cruchaga, Carlos; Goate, Alison M.; Perrin, Richard J.; Wang, Guoqiao; Li, Yan; Shi, Xinyu; Xiong, Chengjie; Pontecorvo, Michael J.; Klein, Gregory; Su, Yi; Klunk, William E.; Jack, Clifford; Koeppe, Robert; Snider, B. Joy; Berman, Sarah B.; Roberson, Erik D.; Brosch, Jared; Surti, Ghulam; Jiménez-Velázquez, Ivonne Z.; Galasko, Douglas; Honig, Lawrence S.; Brooks, William S.; Clarnette, Roger; Wallon, David; Dubois, Bruno; Pariente, Jérémie; Pasquier, Florence; Sanchez-Valle, Raquel; Shcherbinin, Sergey; Higgins, Ixavier; Tunali, Ilke; Masters, Colin L.; van Dyck, Christopher H.; Masellis, Mario; Hsiung, Robin; Gauthier, Serge; Salloway, Steve; Clifford, David B.; Mills, Susan; Supnet-Bell, Charlene; McDade, Eric; Bateman, Randall J.; Benzinger, Tammie L. S.; DIAN-TU Study Team; Neurology, School of MedicinePurpose: Pittsburgh Compound-B (11C-PiB) and 18F-florbetapir are amyloid-β (Aβ) positron emission tomography (PET) radiotracers that have been used as endpoints in Alzheimer's disease (AD) clinical trials to evaluate the efficacy of anti-Aβ monoclonal antibodies. However, comparing drug effects between and within trials may become complicated if different Aβ radiotracers were used. To study the consequences of using different Aβ radiotracers to measure Aβ clearance, we performed a head-to-head comparison of 11C-PiB and 18F-florbetapir in a Phase 2/3 clinical trial of anti-Aβ monoclonal antibodies. Methods: Sixty-six mutation-positive participants enrolled in the gantenerumab and placebo arms of the first Dominantly Inherited Alzheimer Network Trials Unit clinical trial (DIAN-TU-001) underwent both 11C-PiB and 18F-florbetapir PET imaging at baseline and during at least one follow-up visit. For each PET scan, regional standardized uptake value ratios (SUVRs), regional Centiloids, a global cortical SUVR, and a global cortical Centiloid value were calculated. Longitudinal changes in SUVRs and Centiloids were estimated using linear mixed models. Differences in longitudinal change between PET radiotracers and between drug arms were estimated using paired and Welch two sample t-tests, respectively. Simulated clinical trials were conducted to evaluate the consequences of some research sites using 11C-PiB while other sites use 18F-florbetapir for Aβ PET imaging. Results: In the placebo arm, the absolute rate of longitudinal change measured by global cortical 11C-PiB SUVRs did not differ from that of global cortical 18F-florbetapir SUVRs. In the gantenerumab arm, global cortical 11C-PiB SUVRs decreased more rapidly than global cortical 18F-florbetapir SUVRs. Drug effects were statistically significant across both Aβ radiotracers. In contrast, the rates of longitudinal change measured in global cortical Centiloids did not differ between Aβ radiotracers in either the placebo or gantenerumab arms, and drug effects remained statistically significant. Regional analyses largely recapitulated these global cortical analyses. Across simulated clinical trials, type I error was higher in trials where both Aβ radiotracers were used versus trials where only one Aβ radiotracer was used. Power was lower in trials where 18F-florbetapir was primarily used versus trials where 11C-PiB was primarily used. Conclusion: Gantenerumab treatment induces longitudinal changes in Aβ PET, and the absolute rates of these longitudinal changes differ significantly between Aβ radiotracers. These differences were not seen in the placebo arm, suggesting that Aβ-clearing treatments may pose unique challenges when attempting to compare longitudinal results across different Aβ radiotracers. Our results suggest converting Aβ PET SUVR measurements to Centiloids (both globally and regionally) can harmonize these differences without losing sensitivity to drug effects. Nonetheless, until consensus is achieved on how to harmonize drug effects across radiotracers, and since using multiple radiotracers in the same trial may increase type I error, multisite studies should consider potential variability due to different radiotracers when interpreting Aβ PET biomarker data and, if feasible, use a single radiotracer for the best results.