Browsing by Author "Snyder, Peter J."

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    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 Medicine
    Dominantly 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.
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    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 Medicine
    Demonstrating 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.
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    BDNF Val66Met moderates memory impairment, hippocampal function and tau in preclinical autosomal dominant Alzheimer’s disease
    (Oxford, 2016-10) Lim, Yen Ying; Hassenstab, Jason; Cruchaga, Carlos; Goate, Alison; Fagan, Anne M.; Benzinger, Tammie L. S.; Maruff, Paul; Snyder, Peter J.; Masters, Colin L.; Allegri, Ricardo; Chhatwal, Jasmeer; Farlow, Martin R.; Graff-Radford, Neill R.; Laske, Christoph; Levin, Johannes; McDade, Eric; Ringman, John M.; Rossor, Martin N.; Salloway, Stephen; Schofield, Peter R.; Holtzman, David M.; Morris, John C.; Bateman, Randall J.; Department of Neurology, IU School of Medicine
    The brain-derived neurotrophic factor ( BDNF ) Val66Met polymorphism is implicated in synaptic excitation and neuronal integrity, and has previously been shown to moderate amyloid-β-related memory decline and hippocampal atrophy in preclinical sporadic Alzheimer’s disease. However, the effect of BDNF in autosomal dominant Alzheimer’s disease is unknown. We aimed to determine the effect of BDNF Val66Met on cognitive function, hippocampal function, tau and amyloid-β in preclinical autosomal dominant Alzheimer’s disease. We explored effects of apolipoprotein E ( APOE ) ε4 on these relationships. The Dominantly Inherited Alzheimer Network conducted clinical, neuropsychological, genetic, biomarker and neuroimaging measures at baseline in 131 mutation non-carriers and 143 preclinical autosomal dominant Alzheimer’s disease mutation carriers on average 12 years before clinical symptom onset. BDNF genotype data were obtained for mutation carriers (95 Val 66 homozygotes, 48 Met 66 carriers). Among preclinical mutation carriers, Met 66 carriers had worse memory performance, lower hippocampal glucose metabolism and increased levels of cerebrospinal fluid tau and phosphorylated tau (p-tau) than Val 66 homozygotes. Cortical amyloid-β and cerebrospinal fluid amyloid-β 42 levels were significantly different from non-carriers but did not differ between preclinical mutation carrier Val 66 homozygotes and Met 66 carriers. There was an effect of APOE on amyloid-β levels, but not cognitive function, glucose metabolism or tau. As in sporadic Alzheimer’s disease, the deleterious effects of amyloid-β on memory, hippocampal function, and tau in preclinical autosomal dominant Alzheimer’s disease mutation carriers are greater in Met 66 carriers. To date, this is the only genetic factor found to moderate downstream effects of amyloid-β in autosomal dominant Alzheimer’s disease.
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    Blood-based biomarkers for Alzheimer's disease and related dementias: Keys to success and things to consider
    (Elsevier, 2019-11-14) Zetterberg, Henrik; Apostolova, Liana G.; Snyder, Peter J.; Radiology and Imaging Sciences, School of Medicine
    During the last two decades, considerable progress has been made in the field of fluid and imaging biomarkers for neurodegenerative dementias. As a result, the most recent research and clinical guidelines (the National Institute on Aging and Alzheimer's Association, International Working Group 2, National Institute for Health and Care Excellence) incorporate cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers in the diagnostic criteria of dementia and mild cognitive impairment due to Alzheimer's disease (AD) [[1], [2], [3]]. However, as both CSF and amyloid PET examinations require expert knowledge and are of limited availability outside specialized memory clinics, there is no doubt that blood tests would be much easier to implement in clinical medicine and as screening tools when recruiting patients for clinical trials.
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    The cholinergic system in the pathophysiology and treatment of Alzheimer's disease
    (Oxford University Press, 2018-07) Hampel, Harald; Mesulam, M.-Marsel; Cuello, A. Claudio; Farlow, Martin R.; Giacobini, Ezio; Grossberg, George T.; Khachaturian, Ara S.; Vergallo, Andrea; Cavedo, Enrica; Snyder, Peter J.; Khachaturian, Zaven S.; Neurology, IU School of Medicine
    Cholinergic synapses are ubiquitous in the human central nervous system. Their high density in the thalamus, striatum, limbic system, and neocortex suggest that cholinergic transmission is likely to be critically important for memory, learning, attention and other higher brain functions. Several lines of research suggest additional roles for cholinergic systems in overall brain homeostasis and plasticity. As such, the brain's cholinergic system occupies a central role in ongoing research related to normal cognition and age-related cognitive decline, including dementias such as Alzheimer's disease. The cholinergic hypothesis of Alzheimer's disease centres on the progressive loss of limbic and neocortical cholinergic innervation. Neurofibrillary degeneration in the basal forebrain is believed to be the primary cause for the dysfunction and death of forebrain cholinergic neurons, giving rise to a widespread presynaptic cholinergic denervation. Cholinesterase inhibitors increase the availability of acetylcholine at synapses in the brain and are one of the few drug therapies that have been proven clinically useful in the treatment of Alzheimer's disease dementia, thus validating the cholinergic system as an important therapeutic target in the disease. This review includes an overview of the role of the cholinergic system in cognition and an updated understanding of how cholinergic deficits in Alzheimer's disease interact with other aspects of disease pathophysiology, including plaques composed of amyloid-β proteins. This review also documents the benefits of cholinergic therapies at various stages of Alzheimer's disease and during long-term follow-up as visualized in novel imaging studies. The weight of the evidence supports the continued value of cholinergic drugs as a standard, cornerstone pharmacological approach in Alzheimer's disease, particularly as we look ahead to future combination therapies that address symptoms as well as disease progression.