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The A4 trial: Anti-amyloid treatment of asymptomatic Alzheimer's disease
Featured Research Sessions: F3-04: Collaboration for Alzheimer’s Prevention: Common Issues Across Presymptomatic Treatment Trials F3-03-02
ANAESTHESIA, SURGERY AND ALZHEIMER’S DISEASE: INSIGHTS FROM ANIMAL MODELS
Deborah Culley1, Gregory Crosby2, 1Centre for Anaesthesia and Cognitive Function, St. Vincent’s Hospital, Melbourne, Australia; 2Harvard Medical School, Boston, Massachusetts, United States. Background: Postoperative cognitive dysfunction (POCD) and its potential relationship to Alzheimer’s disease (AD) is a topic of considerable clinical interest and debate. Animal models reveal that general anesthesia and surgery, together or individually, can produce enduring cognitive impairment, neuroinflammation, and changes in proteins implicated in AD such as amyloid ß and tau. As such, preclinical research has helped enormously to inform, if not drive, the debate linking anesthesia and surgery to cognitive decline. This presentation will review the relevant preclinical data from animal models on this topic, with particular attention to the implications and limitations of extrapolating such work to humans. Methods: We will use published studies to critically review and discuss the influence of general anesthesia and surgery on animal learning and brain biochemistry as it relates to neuroinflammation and pathogenesis of AD. We will focus on age, anesthetic and surgical conditions, and the common behavioral methods (e.g. spontaneous alternations; Morris water maze; radial arm maze; fear conditioning) employed to assess learning and memory in animals in order to illustrate both the strengths and weaknesses of the data for establishing linkages between anesthesia/surgery and POCD/AD. Results: Preclinical research shows that a surgical procedure and/or general anesthesia with certain agents produces a neuroinflammatory response in the brain, increases amyloid ß and phosphorylated tau, and that these events are associated with learning impairment. Moreover, an AD-like phenotype seems to increase vulnerability to these anesthesia / surgery-induced changes. Thus far, however, much of the work has been done in adult rather than old animals; there is no consensus about neurobehavioral assessment and therefore studies are somewhat difficult to interpret; evidence is lacking for acceleration of cognitive decline in AD transgenic animals following anesthesia; and a causal relationship between anesthetic-induced changes in amyloid ß or phospho-tau and cognitive impairment has not been demonstrated. Conclusions: Animal models have contributed substantially to understanding the pathophysiology and mechanisms of surgery and/or general anesthesia-induced cognitive decline but much more preclinical (and clinical) work is necessary to establish that anesthesia and surgery cause AD. F3-03-03
IS GENERAL ANAESTHESIA A RISK FACTOR FOR ALZHEIMER’S? CLUES FROM BIOMARKERS
Robert Whittington1, Emmanuel Planel2, 1Columbia University Medical Center, New York, New York, United States; 2Harvard Medical School, Boston, Massachusetts, United States. Background: Cognitive disorders such as post-operative cognitive dysfunction (POCD), confusion, and delirium, are common following anesthesia in the elderly. Interestingly, it has been suggested that the pathological mechanism(s) underlying POCD mimic AD. Indeed, anesthesia might be a risk factor for the development of neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. Patients with AD are considered to be particularly at risk for some of the cognitive side effects of anesthesia, and there is also now concern that general anesthesia is a risk factor for AD, with in vitro and in vivo studies suggesting that anesthetics may promote and intensify the neuropathogenesis of AD. Methods: After a short review of the clinical literature on anesthesia and AD, we will focus on describing the impact of anesthesia on the two pathological hallmarks of AD: betaamyloid (Ab) accumulation and aberrant tau phosphorylation and aggregation, with an emphasis on our most recent data. Results: Evidence from in vitro and animal models demonstrate that exposure to inhaled anesthetics, such as isoflurane and halothane, can increase Ab production, enhance Ab oligomerization, and promote plaque formation, while exposure to intravenous anesthetics, such as propofol, thiopental or chloral hydrate,
P425
has no effect. We have also demonstrated that exposure to isoflurane could lead to tau hyperphosphorylation, detachment from microtubules and enhanced aggregation in vivo, albeit indirectly, by inducing hypothermia in mouse models of tauopathies. On the other hand, some anesthetics such as propofol also have a direct effect on tau phosphorylation, as demonstrated by maintaining the animals normothermic. Conclusions: While there has been clinical interest on the relation between anesthesia and AD for at least a quarter of a century, the biochemical consequences of anesthesia on AD neuropathogenic pathways have only begun to be studied very recently. Overall, epidemiological evidence establishing a link between anesthetic exposure and the risk of AD remains controversial. On the other hand, clinical studies examining AD biomarkers postoperatively, and preclinical studies exploring the impact of anesthetics on Ab and tau, converge to indicate that anesthetics could affect AD pathogenesis, either directly or indirectly. F3-03-04
POSTOPERATIVE COGNITIVE DYSFUNCTION AND DELIRIUM
Jacob Steinmetz1, Lars S. Rasmussen2, 1Centre for Anaesthesia and Cognitive Function, St. Vincent’s Hospital, Melbourne, Australia; 2 Rigshospitalet–Copenhagen University Hospital, Copenhagen, Denmark. Background: Due to the population aging, the number of elderly patients undergoing surgery is increasing. Elderly patients are particularly at risk of experiencing cognitive impairment postoperatively. Two of these common complications are called postoperative delirium and postoperative cognitive dysfunction. Methods: Delirium is quite frequent in the first few days after surgery. The syndrome is characterized by an acute onset and a disturbance of attention and reduced awareness of the surroundings and it tends to fluctuate during the course of the day. Delirium is well defined as a diagnosis, and since there are various presentations of symptoms, different forms of delirium exist. Contrary to delirium, patients with Postoperative cognitive dysfunction (POCD) have a level of consciousness that is unaffected. The condition is usually detected weeks to months after surgery, and it is characterized by subtle deterioration in memory, abstract thinking and attention. It can only be confirmed by the use of a neuropsychological test battery but unfortunately a strict definition does not exist. Due to various methodological problems it is recommended to use a control group undergoing the same tests but not undergoing surgery. Results: The incidence of postoperative delirium is around 15% in elderly surgical patients, and it is associated with increased morbidity and mortality. Many studies on POCD is published within the field of cardiac surgery, but even after non-cardiac surgery the condition is as frequent as 25% of elderly patients at one week after major surgery. The condition is largely reversible, and the incidence is around 10% after three months. There are several risk factors associated with both conditions, primarily increasing age and presumably preexisting cognitive impairment, but the etiology of POCD is for the most part unknown, although most agree it is due to multiple factors, including stress, inflammation , and hospitalization. Regional anesthesia does not seem to reduce the risk of cognitive dysfunction beyond one week after surgery. Both syndromes are associated with serious long term effects. Conclusions: Postoperative delirium and cognitive dysfunction are important cerebral complications after cardiac as well as non-cardiac surgery especially in the elderly. Both conditions can have severe long term consequences. FEATURED RESEARCH SESSIONS: F3-04 COLLABORATION FOR ALZHEIMER’S PREVENTION: COMMON ISSUES ACROSS PRESYMPTOMATIC TREATMENT TRIALS F3-04-01
THE A4 TRIAL: ANTI-AMYLOID TREATMENT OF ASYMPTOMATIC ALZHEIMER’S DISEASE
Reisa Sperling1, Michael Donohue2, Paul Aisen2, 1Washington University School of Medicine, St. Louis, Missouri, United States; 2University of California, San Diego, San Diego, California, United States.
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Featured Research Sessions: F3-04: Collaboration for Alzheimer’s Prevention: Common Issues Across Presymptomatic Treatment Trials
Background: Disappointing results from recent clinical trials and transgenic animal experiments suggest that we may be testing anti-Ab therapies much too late in the pathophysiological process of Alzheimer’s disease (AD). Converging data from PET amyloid imaging, cerebrospinal fluid studies, and large autopsy series suggest that approximately one-third of clinically normal older individuals harbor a substantial burden of cerebral amyloid-b. These amyloid-positive “normals” demonstrate evidence of functional and structural imaging abnormalities, elevation of CSF tau, and subtle cognitive deficits, consistent with the preclinical stages of AD, and represent an ideal population for a large secondary prevention effort to slow cognitive decline. Methods: The Alzheimer’s Disease Cooperative Study (ADCS) is proposing a placebo-controlled, 3-year trial in clinically normal older individuals with biomarker evidence of AD pathology. The primary outcome will be slowing the rate of decline on a cognitive composite, with multiple biomarkers as secondary outcomes. Eligible subjects will be clinically normal (CDR 0, MMSE 27-30), over age 70, and will have evidence of amyloid-positivity on PET amyloid imaging. The choice of treatment has not yet been finalized, but will be a monoclonal antibody with clear evidence of target engagement and adequate safety data to support a 3-year trial. Results: Analyses using available data from the Alzheimer’s Disease Neuroimaging Initiative and Australian Imaging Biomarkers Lifestyle study consistently demonstrate evidence of an increased rate of cognitive decline in amyloid-positive normals, and that approximately n¼500 subjects per arm will yield adequate power to detect a 25-35% treatment-related decrease in the rate of cognitive decline. We will also include a natural history arm of 500 amyloid-negative individuals to investigate the specific pattern of “amyloid-related” decline and to develop more sensitive outcome measures to improve the efficiency of future secondary prevention trials in preclinical AD. Conclusions: The A4 trial will provide complementary information to the prevention initiatives being planned in genetic-risk cohorts. Although amyloid-b may be only one of several pathogenic factors in the elderly population, we now have the biomarker tools and biologically active compounds to test the hypothesis that altering “upstream” amyloid burden will impact “downstream” neurodegeneration and delay or prevent cognitive decline. F3-04-02
THE DOMINANTLY INHERITED ALZHEIMER’S NETWORK TRIALS: AN OPPORTUNITY TO PREVENT ALZHEIMER’S DISEASE
Randall Bateman, John Morris, Washington University School of Medicine, St. Louis, Missouri, United States. Background: Prevention studies are likely to be most successful for those with the highest risk of AD. Autsomal dominant AD accounts for less than 1% of all AD, but has 100% risk and usually occurs in the third to fifth decade of life. In 2008, the NIH funded the establishment of the Dominantly Inherited Alzheimer Network (DIAN, U01AG032438, JC Morris, PI; www. dian-info.org), an international network of leading research centers to investigate AD caused by mutations. The DIAN is the largest and most extensive worldwide network for mutation Alzheimer’s research. In collaboration with other prevention initiatives, DIAN is preparing to launch the first prevention trials for autosomal dominant AD. Methods: Measurements to track disease progression using established clinical, cognitive, imaging and biomarker methods have been performed. The results from the study demonstrate the feasibility and promise of performing prevention studies in the DIAN population. In 2011, the DIAN Therapeutic Trials Unit (TTU) was established with funding from the Alzheimer’s Association and a consortium of ten pharmaceutical companies (the DIAN Pharma Consortium). The purpose of the DIAN TTU is to direct the design and management of prevention and interventional trials of DIAN participants. Results: A sequence of biomarker changes reveal a cascade of events beginning 10-20 years before the first symptoms of AD are manifest. The proposed design for the DIAN prevention trials is a two-phase study to delay, prevent, or restore cognitive loss in AD mutation carriers. The first phase will determine the biological engagement of the drug target and impact on biomarkers of neurodegeneration with imaging, cerebrospinal fluid, and other biomarkers. The second phase will determine if there is a cognitive benefit of treatment. Conclusions: Be-
cause the clinical and pathological phenotypes of dominantly inherited AD appear similar to those for the far more common late-onset “sporadic” AD, the nature and sequence of brain changes in early-onset AD are also likely relevant for late-onset AD. Clinical studies in AD caused by gene mutations are likely to pioneer the way to prevention trials for all forms of AD. The scientific knowledge gained from secondary prevention trials is likely to inform about the cause of AD, validate biomarkers to accelerate treatment development, and determine the effects of treating AD early. F3-04-03
THE ALZHEIMER’S PREVENTION INITIATIVE 1
Eric Reiman , Francisco Lopera2, Jessica Langbaum1, Adam Fleisher1, Napatkamon Ayutyanont1, Yakeel Quiroz3, Laura Jakimovich1, Carolyn Langlois1, Pierre Tariot1, 1Banner Alzheimer’s Institute, Phoenix, Arizona, United States; 2Grupo de Neurociencias, Universidad de Antioquia, Medellın, Colombia; 3Boston University, Boston, Massachusetts, United States. Background: There is an urgent need to find demonstrably effective presymptomatic Alzheimer’s disease (AD) treatments, those interventions intended to postpone the onset, reduce the risk of, or completely prevent AD symptoms. The Alzheimer’s Prevention Initiative (API) aims to conduct presymptomatic AD treatment trials of amyloid-modifying treatments in cognitively normal people, who based on their age and genetic background, are at the highest imminent risk of AD symptoms; to relate a treatment’s biomarker effects to clinical outcome; to provide a best test of the amyloid hypothesis; to give persons at highest risk access to promising investigational treatments; to provide exceptionally large Alzheimer’s Prevention registries for these and other presymptomatic trials; and to complement, support and benefit from other initiatives. Methods: The API includes a) a planned presymptomatic AD treatment/biomarker development/nested cohort trial in cognitively normal early-onset AD-causing mutation carriers within 15 years of their estimated age at clinical onset, including PS1 E280A mutation carriers from the world’s largest kindred in Antioquia, Colombia; b) a proposed presymptomatic AD treatment/biomarker development trial in cognitively normal APOE ^Im4 homozygotes and heterozygotes; c) an exceptionally large early-onset AD prevention registry in the PS1 E280A kindred; and d) development of an exceptionally large internet-based Alzheimer’s Prevention Registry to support the entire research community. Results: We continue to characterize the preclinical trajectory of early-onset and late-onset AD in our PS1 E280A and APOE cohorts, establish a composite cognitive endpoint with improved power to track evaluate presymptomatic AD treatments; estimated presymptomatic trial sample sizes using amyloid PET, FDG PET, MRI, CSF and cognitive endpoints, vet treatment options for these and other trials, engage a large number of academic, industry and regulatory stakeholders; launch our registries; and prepare for our first presymptomatic trial. Conclusions: We are excited about our progress, plans, current timelines and the chance to work with other researchers, programs, and stakeholders. Together, we have a chance to set the stage of a new era in AD prevention research, develop the resources, biomarker endpoints, and accelerated regulatory approval pathway needed to rapidly evaluate the range of promising presymptomatic treatments, and find ones that work as soon as possible. F3-04-04
PRESYMPTOMATIC TREATMENT TRIALS: A MODERATED PANEL DISCUSSION
Howard Feldman1, Stacie Weninger2, 1Banner Alzheimer’s Institute, Phoenix, Arizona; 2Fidelity Biosciences Research Initiative, Boston, Massachusetts, United States. Background: The Collaboration for Alzheimer’s Prevention (CAP) was established to help ensure harmonization on key issues facing three groups (ADCS, DIAN, API) planning, and preparing to implement, presymptomatic Alzheimer’s disease treatment trials. Several cross-cutting themes have emerged across the three programs that will be discussed in a 45 minute moderated panel format that includes the speakers as well as international
ANAESTHESIA, SURGERY AND ALZHEIMER’S DISEASE: INSIGHTS FROM ANIMAL MODELS
Deborah Culley1, Gregory Crosby2, 1Centre for Anaesthesia and Cognitive Function, St. Vincent’s Hospital, Melbourne, Australia; 2Harvard Medical School, Boston, Massachusetts, United States. Background: Postoperative cognitive dysfunction (POCD) and its potential relationship to Alzheimer’s disease (AD) is a topic of considerable clinical interest and debate. Animal models reveal that general anesthesia and surgery, together or individually, can produce enduring cognitive impairment, neuroinflammation, and changes in proteins implicated in AD such as amyloid ß and tau. As such, preclinical research has helped enormously to inform, if not drive, the debate linking anesthesia and surgery to cognitive decline. This presentation will review the relevant preclinical data from animal models on this topic, with particular attention to the implications and limitations of extrapolating such work to humans. Methods: We will use published studies to critically review and discuss the influence of general anesthesia and surgery on animal learning and brain biochemistry as it relates to neuroinflammation and pathogenesis of AD. We will focus on age, anesthetic and surgical conditions, and the common behavioral methods (e.g. spontaneous alternations; Morris water maze; radial arm maze; fear conditioning) employed to assess learning and memory in animals in order to illustrate both the strengths and weaknesses of the data for establishing linkages between anesthesia/surgery and POCD/AD. Results: Preclinical research shows that a surgical procedure and/or general anesthesia with certain agents produces a neuroinflammatory response in the brain, increases amyloid ß and phosphorylated tau, and that these events are associated with learning impairment. Moreover, an AD-like phenotype seems to increase vulnerability to these anesthesia / surgery-induced changes. Thus far, however, much of the work has been done in adult rather than old animals; there is no consensus about neurobehavioral assessment and therefore studies are somewhat difficult to interpret; evidence is lacking for acceleration of cognitive decline in AD transgenic animals following anesthesia; and a causal relationship between anesthetic-induced changes in amyloid ß or phospho-tau and cognitive impairment has not been demonstrated. Conclusions: Animal models have contributed substantially to understanding the pathophysiology and mechanisms of surgery and/or general anesthesia-induced cognitive decline but much more preclinical (and clinical) work is necessary to establish that anesthesia and surgery cause AD. F3-03-03
IS GENERAL ANAESTHESIA A RISK FACTOR FOR ALZHEIMER’S? CLUES FROM BIOMARKERS
Robert Whittington1, Emmanuel Planel2, 1Columbia University Medical Center, New York, New York, United States; 2Harvard Medical School, Boston, Massachusetts, United States. Background: Cognitive disorders such as post-operative cognitive dysfunction (POCD), confusion, and delirium, are common following anesthesia in the elderly. Interestingly, it has been suggested that the pathological mechanism(s) underlying POCD mimic AD. Indeed, anesthesia might be a risk factor for the development of neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. Patients with AD are considered to be particularly at risk for some of the cognitive side effects of anesthesia, and there is also now concern that general anesthesia is a risk factor for AD, with in vitro and in vivo studies suggesting that anesthetics may promote and intensify the neuropathogenesis of AD. Methods: After a short review of the clinical literature on anesthesia and AD, we will focus on describing the impact of anesthesia on the two pathological hallmarks of AD: betaamyloid (Ab) accumulation and aberrant tau phosphorylation and aggregation, with an emphasis on our most recent data. Results: Evidence from in vitro and animal models demonstrate that exposure to inhaled anesthetics, such as isoflurane and halothane, can increase Ab production, enhance Ab oligomerization, and promote plaque formation, while exposure to intravenous anesthetics, such as propofol, thiopental or chloral hydrate,
P425
has no effect. We have also demonstrated that exposure to isoflurane could lead to tau hyperphosphorylation, detachment from microtubules and enhanced aggregation in vivo, albeit indirectly, by inducing hypothermia in mouse models of tauopathies. On the other hand, some anesthetics such as propofol also have a direct effect on tau phosphorylation, as demonstrated by maintaining the animals normothermic. Conclusions: While there has been clinical interest on the relation between anesthesia and AD for at least a quarter of a century, the biochemical consequences of anesthesia on AD neuropathogenic pathways have only begun to be studied very recently. Overall, epidemiological evidence establishing a link between anesthetic exposure and the risk of AD remains controversial. On the other hand, clinical studies examining AD biomarkers postoperatively, and preclinical studies exploring the impact of anesthetics on Ab and tau, converge to indicate that anesthetics could affect AD pathogenesis, either directly or indirectly. F3-03-04
POSTOPERATIVE COGNITIVE DYSFUNCTION AND DELIRIUM
Jacob Steinmetz1, Lars S. Rasmussen2, 1Centre for Anaesthesia and Cognitive Function, St. Vincent’s Hospital, Melbourne, Australia; 2 Rigshospitalet–Copenhagen University Hospital, Copenhagen, Denmark. Background: Due to the population aging, the number of elderly patients undergoing surgery is increasing. Elderly patients are particularly at risk of experiencing cognitive impairment postoperatively. Two of these common complications are called postoperative delirium and postoperative cognitive dysfunction. Methods: Delirium is quite frequent in the first few days after surgery. The syndrome is characterized by an acute onset and a disturbance of attention and reduced awareness of the surroundings and it tends to fluctuate during the course of the day. Delirium is well defined as a diagnosis, and since there are various presentations of symptoms, different forms of delirium exist. Contrary to delirium, patients with Postoperative cognitive dysfunction (POCD) have a level of consciousness that is unaffected. The condition is usually detected weeks to months after surgery, and it is characterized by subtle deterioration in memory, abstract thinking and attention. It can only be confirmed by the use of a neuropsychological test battery but unfortunately a strict definition does not exist. Due to various methodological problems it is recommended to use a control group undergoing the same tests but not undergoing surgery. Results: The incidence of postoperative delirium is around 15% in elderly surgical patients, and it is associated with increased morbidity and mortality. Many studies on POCD is published within the field of cardiac surgery, but even after non-cardiac surgery the condition is as frequent as 25% of elderly patients at one week after major surgery. The condition is largely reversible, and the incidence is around 10% after three months. There are several risk factors associated with both conditions, primarily increasing age and presumably preexisting cognitive impairment, but the etiology of POCD is for the most part unknown, although most agree it is due to multiple factors, including stress, inflammation , and hospitalization. Regional anesthesia does not seem to reduce the risk of cognitive dysfunction beyond one week after surgery. Both syndromes are associated with serious long term effects. Conclusions: Postoperative delirium and cognitive dysfunction are important cerebral complications after cardiac as well as non-cardiac surgery especially in the elderly. Both conditions can have severe long term consequences. FEATURED RESEARCH SESSIONS: F3-04 COLLABORATION FOR ALZHEIMER’S PREVENTION: COMMON ISSUES ACROSS PRESYMPTOMATIC TREATMENT TRIALS F3-04-01
THE A4 TRIAL: ANTI-AMYLOID TREATMENT OF ASYMPTOMATIC ALZHEIMER’S DISEASE
Reisa Sperling1, Michael Donohue2, Paul Aisen2, 1Washington University School of Medicine, St. Louis, Missouri, United States; 2University of California, San Diego, San Diego, California, United States.
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Featured Research Sessions: F3-04: Collaboration for Alzheimer’s Prevention: Common Issues Across Presymptomatic Treatment Trials
Background: Disappointing results from recent clinical trials and transgenic animal experiments suggest that we may be testing anti-Ab therapies much too late in the pathophysiological process of Alzheimer’s disease (AD). Converging data from PET amyloid imaging, cerebrospinal fluid studies, and large autopsy series suggest that approximately one-third of clinically normal older individuals harbor a substantial burden of cerebral amyloid-b. These amyloid-positive “normals” demonstrate evidence of functional and structural imaging abnormalities, elevation of CSF tau, and subtle cognitive deficits, consistent with the preclinical stages of AD, and represent an ideal population for a large secondary prevention effort to slow cognitive decline. Methods: The Alzheimer’s Disease Cooperative Study (ADCS) is proposing a placebo-controlled, 3-year trial in clinically normal older individuals with biomarker evidence of AD pathology. The primary outcome will be slowing the rate of decline on a cognitive composite, with multiple biomarkers as secondary outcomes. Eligible subjects will be clinically normal (CDR 0, MMSE 27-30), over age 70, and will have evidence of amyloid-positivity on PET amyloid imaging. The choice of treatment has not yet been finalized, but will be a monoclonal antibody with clear evidence of target engagement and adequate safety data to support a 3-year trial. Results: Analyses using available data from the Alzheimer’s Disease Neuroimaging Initiative and Australian Imaging Biomarkers Lifestyle study consistently demonstrate evidence of an increased rate of cognitive decline in amyloid-positive normals, and that approximately n¼500 subjects per arm will yield adequate power to detect a 25-35% treatment-related decrease in the rate of cognitive decline. We will also include a natural history arm of 500 amyloid-negative individuals to investigate the specific pattern of “amyloid-related” decline and to develop more sensitive outcome measures to improve the efficiency of future secondary prevention trials in preclinical AD. Conclusions: The A4 trial will provide complementary information to the prevention initiatives being planned in genetic-risk cohorts. Although amyloid-b may be only one of several pathogenic factors in the elderly population, we now have the biomarker tools and biologically active compounds to test the hypothesis that altering “upstream” amyloid burden will impact “downstream” neurodegeneration and delay or prevent cognitive decline. F3-04-02
THE DOMINANTLY INHERITED ALZHEIMER’S NETWORK TRIALS: AN OPPORTUNITY TO PREVENT ALZHEIMER’S DISEASE
Randall Bateman, John Morris, Washington University School of Medicine, St. Louis, Missouri, United States. Background: Prevention studies are likely to be most successful for those with the highest risk of AD. Autsomal dominant AD accounts for less than 1% of all AD, but has 100% risk and usually occurs in the third to fifth decade of life. In 2008, the NIH funded the establishment of the Dominantly Inherited Alzheimer Network (DIAN, U01AG032438, JC Morris, PI; www. dian-info.org), an international network of leading research centers to investigate AD caused by mutations. The DIAN is the largest and most extensive worldwide network for mutation Alzheimer’s research. In collaboration with other prevention initiatives, DIAN is preparing to launch the first prevention trials for autosomal dominant AD. Methods: Measurements to track disease progression using established clinical, cognitive, imaging and biomarker methods have been performed. The results from the study demonstrate the feasibility and promise of performing prevention studies in the DIAN population. In 2011, the DIAN Therapeutic Trials Unit (TTU) was established with funding from the Alzheimer’s Association and a consortium of ten pharmaceutical companies (the DIAN Pharma Consortium). The purpose of the DIAN TTU is to direct the design and management of prevention and interventional trials of DIAN participants. Results: A sequence of biomarker changes reveal a cascade of events beginning 10-20 years before the first symptoms of AD are manifest. The proposed design for the DIAN prevention trials is a two-phase study to delay, prevent, or restore cognitive loss in AD mutation carriers. The first phase will determine the biological engagement of the drug target and impact on biomarkers of neurodegeneration with imaging, cerebrospinal fluid, and other biomarkers. The second phase will determine if there is a cognitive benefit of treatment. Conclusions: Be-
cause the clinical and pathological phenotypes of dominantly inherited AD appear similar to those for the far more common late-onset “sporadic” AD, the nature and sequence of brain changes in early-onset AD are also likely relevant for late-onset AD. Clinical studies in AD caused by gene mutations are likely to pioneer the way to prevention trials for all forms of AD. The scientific knowledge gained from secondary prevention trials is likely to inform about the cause of AD, validate biomarkers to accelerate treatment development, and determine the effects of treating AD early. F3-04-03
THE ALZHEIMER’S PREVENTION INITIATIVE 1
Eric Reiman , Francisco Lopera2, Jessica Langbaum1, Adam Fleisher1, Napatkamon Ayutyanont1, Yakeel Quiroz3, Laura Jakimovich1, Carolyn Langlois1, Pierre Tariot1, 1Banner Alzheimer’s Institute, Phoenix, Arizona, United States; 2Grupo de Neurociencias, Universidad de Antioquia, Medellın, Colombia; 3Boston University, Boston, Massachusetts, United States. Background: There is an urgent need to find demonstrably effective presymptomatic Alzheimer’s disease (AD) treatments, those interventions intended to postpone the onset, reduce the risk of, or completely prevent AD symptoms. The Alzheimer’s Prevention Initiative (API) aims to conduct presymptomatic AD treatment trials of amyloid-modifying treatments in cognitively normal people, who based on their age and genetic background, are at the highest imminent risk of AD symptoms; to relate a treatment’s biomarker effects to clinical outcome; to provide a best test of the amyloid hypothesis; to give persons at highest risk access to promising investigational treatments; to provide exceptionally large Alzheimer’s Prevention registries for these and other presymptomatic trials; and to complement, support and benefit from other initiatives. Methods: The API includes a) a planned presymptomatic AD treatment/biomarker development/nested cohort trial in cognitively normal early-onset AD-causing mutation carriers within 15 years of their estimated age at clinical onset, including PS1 E280A mutation carriers from the world’s largest kindred in Antioquia, Colombia; b) a proposed presymptomatic AD treatment/biomarker development trial in cognitively normal APOE ^Im4 homozygotes and heterozygotes; c) an exceptionally large early-onset AD prevention registry in the PS1 E280A kindred; and d) development of an exceptionally large internet-based Alzheimer’s Prevention Registry to support the entire research community. Results: We continue to characterize the preclinical trajectory of early-onset and late-onset AD in our PS1 E280A and APOE cohorts, establish a composite cognitive endpoint with improved power to track evaluate presymptomatic AD treatments; estimated presymptomatic trial sample sizes using amyloid PET, FDG PET, MRI, CSF and cognitive endpoints, vet treatment options for these and other trials, engage a large number of academic, industry and regulatory stakeholders; launch our registries; and prepare for our first presymptomatic trial. Conclusions: We are excited about our progress, plans, current timelines and the chance to work with other researchers, programs, and stakeholders. Together, we have a chance to set the stage of a new era in AD prevention research, develop the resources, biomarker endpoints, and accelerated regulatory approval pathway needed to rapidly evaluate the range of promising presymptomatic treatments, and find ones that work as soon as possible. F3-04-04
PRESYMPTOMATIC TREATMENT TRIALS: A MODERATED PANEL DISCUSSION
Howard Feldman1, Stacie Weninger2, 1Banner Alzheimer’s Institute, Phoenix, Arizona; 2Fidelity Biosciences Research Initiative, Boston, Massachusetts, United States. Background: The Collaboration for Alzheimer’s Prevention (CAP) was established to help ensure harmonization on key issues facing three groups (ADCS, DIAN, API) planning, and preparing to implement, presymptomatic Alzheimer’s disease treatment trials. Several cross-cutting themes have emerged across the three programs that will be discussed in a 45 minute moderated panel format that includes the speakers as well as international