Amyloid-Related Imaging Abnormalities in the DIAN-TU-001 Trial of Gantenerumab and Solanezumab: Lessons from a Trial in Dominantly Inherited Alzheimer Disease

Tailoring MAPK Pathways: New Therapeutic Avenues for Treating Alzheimer's Disease

Alzheimer's disease (AD) is irreversible, progressive, and refractory in nature and is managed very poorly clinically due to very limited treatment outcomes. Unfortunately, most of the multiple clinical trials involving AD patients were unsuccessful in improving the disease prognosis. At the cellular level, many signaling pathways have been proposed to be involved in the sterile/refractory behavior of degenerating neurons in AD. Due to the involvement of p38MAPK in the pathogenesis of Alzheimer's disease, numerous investigations have attempted to determine the beneficial effects of MAPK targeting on memory, inflammatory programming of the brain, and synaptic plasticity. In view of this, various clinical trials involving several MAPK inhibitors (with good safety profiles and few side effects) have yielded positive results in AD patients, suggesting that MAPK targeting may be effective for reducing the pathogenesis of AD, but due to selectivity, dosing, and patient stratification, this aspect still needs further development. In view of their selectivity and off-target effects, only a few MAPK inhibitors have been employed in clinical trials against AD, indicating the scope of their development in this area. Therefore, this study focused on MAPK-based interventions as an upcoming and innovative approach for alleviating AD, with a special emphasis on clinical studies.

Lecanemab for early Alzheimer's disease: Appropriate use recommendations from the French federation of memory clinics

Lecanemab, a monoclonal antibody targeting β-amyloid protofibrils, has shown promising results in a Phase III clinical trial for the treatment of early stages of Alzheimer's disease (AD) and has been approved by the European Medicines Agency. An Early Market Authorization could be submitted to the French regulatory agencies, potentially allowing for the drug's use in clinical practice in France in 2025. To guide French clinicians in administering lecanemab in a standardized way, the French Federation of Memory Clinics has developed appropriate use recommendations for lecanemab that highlight relevant questions established to ensure an optimal risk-benefit ratio. The recommendations emphasize that lecanemab treatment requires a comprehensive individualized evaluation of the risk-benefit ratio, which should occur in multidisciplinary meetings. When approved, the guidelines support the use of blood biomarkers, proposing specific cutoffs for patients eligible for lecanemab under restricted conditions. In addition to the European Medicines Agency restrictions in patients on anticoagulants, and APOE4 homozygotes, the guidelines recommend against lecanemab treatment for patients with high amyloid-related hemorrhagic risk such as probable cerebral amyloid angiopathy (Boston criteria v1.5) until further data become available. Additionally, we recommend that MRI monitoring be started before the third infusion to account for early Amyloid Related Imaging Abnormalities (ARIA) occurring on lecanemab. It is recommended to establish a specific clinical care pathway with protocols for patients with ARIA, with trained physicians and radiologists with expertise in neurological emergency and intensive care. Finally, a discontinuation protocol based on dementia severity assessment after 18 months of lecanemab treatment is suggested. Access to lecanemab requires a personalized biological and genetic diagnosis of AD, which is currently not necessary in most cases. Therefore, the healthcare system must rapidly adjust to new diagnostic procedures and treatment delivery to ensure equal access for all individuals.

Mining and analysis of adverse events associated with aducanumab: a real-world study using FDA Adverse Event Reporting System database

BACKGROUND

Aducanumab, a monoclonal antibody, received approval for the treatment of Alzheimer's disease in 2021. However, it remains controversial over the security of this drug. In this study, aducanumab-related adverse events (AEs) were evaluated through data mining based on the FDA Adverse Event Reporting System (FAERS) database.

RESEARCH DESIGN AND METHODS

The AE reports induced by aducanumab as the primary suspected drug were extracted from the FAERS database. The clinical characteristics of aducanumab-associated reports were analyzed. The potential new AE signals of aducanumab were explored using four disproportionality analysis methods. Furthermore, the difference in aducanumab-associated AE signals was investigated concerning sex, age, weight, dose, onset time, and continent.

RESULTS

In total, 328 reports and 793 AEs associated with aducanumab were identified. Six new AEs were identified. No significant sex and weight difference in aducanumab-related signals was found. Notably, nervous system disorders, especially 'amyloid related imaging abnormality-edema/effusion' and 'amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits,' were more frequently to be reported within 121-240 days, particularly in Europe.

CONCLUSIONS

This study contributes real-world evidence regarding the safety of aducanumab.

Amyloid-related imaging abnormalities: manifestations, metrics and mechanisms

Three monoclonal antibodies directed against specific forms of the amyloid-β (Aβ) peptide have been granted accelerated or traditional approval by the FDA as treatments for Alzheimer disease, representing the first step towards bringing disease-modifying treatments for this disease into clinical practice. Here, we review the detection, underlying pathophysiological mechanisms and clinical implications of amyloid-related imaging abnormalities (ARIA), the most impactful adverse effect of anti-Aβ immunotherapy. ARIA appears as regions of oedema or effusions (ARIA-E) in brain parenchyma or sulci or as haemorrhagic lesions (ARIA-H) in the form of cerebral microbleeds, convexity subarachnoid haemorrhage, cortical superficial siderosis or intracerebral haemorrhage. Analysis of the radiographic appearance of ARIA, its clinical risk factors and underlying neuropathology, and results from animal models point to a central role for cerebral amyloid angiopathy - a condition characterized by cerebrovascular Aβ deposits - as a key component, either as a direct target for antibody-mediated inflammation or as recipient of Aβ mobilized from plaques in the Alzheimer brain parenchyma. The great majority of ARIA occurrences are associated with mild or no clinical symptoms. However, ~5% of all ARIA events are severe enough to result in hospitalization, permanent disability or death and thus raise challenging clinical questions regarding patient selection and use of concomitant agents. Therefore, identifying novel approaches to predicting, modelling, preventing and treating ARIA remains a key step towards allowing safe use of anti-Aβ immunotherapy for the world's rapidly ageing population.

Safety and efficacy of long-term gantenerumab treatment in dominantly inherited Alzheimer's disease: an open-label extension of the phase 2/3 multicentre, randomised, double-blind, placebo-controlled platform DIAN-TU trial

BACKGROUND

Amyloid plaque removal by monoclonal antibody therapies slows clinical progression in symptomatic Alzheimer's disease; however, the potential for delaying the onset of clinical symptoms in asymptomatic people is unknown. The Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU) is an ongoing platform trial assessing the safety and efficacy of multiple investigational products in participants with dominantly inherited Alzheimer's disease (DIAD). Based on findings of amyloid removal and downstream biological effects from the gantenerumab group of the platform trial, we continued a 3-year open-label extension (OLE) study to assess the safety and efficacy of long-term treatment with high doses of gantenerumab.

METHODS

The randomised, placebo-controlled, double-blind, phase 2/3 multi-arm trial (DIAN-TU-001) assessed solanezumab or gantenerumab versus placebo in participants who were between 15 years before and 10 years after their estimated years to symptom onset and who had a Clinical Dementia Rating (CDR) global score of 0 (cognitively normal) to 1 (mild dementia). This study was followed by an OLE study of gantenerumab treatment, conducted at 18 study sites in Australia, Canada, France, Ireland, Puerto Rico, Spain, the UK, and the USA. For inclusion in the OLE, participants at risk for DIAD had participated in the double-blind period of DIAN-TU-001 and were required to know their mutation status. We investigated increasing doses of subcutaneous gantenerumab up to 1500 mg every 2 weeks. Due to the lack of a regulatory path for gantenerumab, the study was stopped early after a prespecified interim analysis (when most participants had completed 2 years of treatment) of the clinical measure CDR-Sum of Boxes (CDR-SB). The primary outcome for the final analysis was the amyloid plaque measure 11C-Pittsburgh compound-B positron emission tomography (PiB-PET) standardised uptake value ratio (SUVR [PiB-PET SUVR]) at 3 years, assessed in the modified intention-to-treat group (mITT; defined as participants who received any gantenerumab treatment post-OLE baseline, had at least one PiB-PET SUVR assessment before gantenerumab treatment, and a post-baseline assessment). All participants who received at least one dose of study drug in the OLE were included in the safety analysis. DIAN-TU-001 (NCT01760005) and the OLE (NCT06424236) are registered with ClinicalTrials.gov.

FINDINGS

Of 74 participants who were recruited into the OLE study between June 3, 2020, and April 22, 2021, 73 were enrolled and received gantenerumab treatment. 47 (64%) stopped dosing due to early termination of the study by the sponsor, and 13 (18%) prematurely discontinued the study for other reasons; 13 people completed 3 years of treatment. The mITT group for the primary analysis comprised 55 participants. At the interim analysis, the hazard ratio for clinical decline of CDR-SB in asymptomatic mutation carriers was 0·79 (n=53 [95% CI 0·47 to 1·32]) for participants who were treated with gantenerumab in either the double-blind or OLE period (Any Gant), and 0·53 (n=22 [0·27 to 1·03]) for participants who were treated with gantenerumab the longest (Longest Gant). At the final analysis, the adjusted mean change from OLE baseline to year 3 in PiB-PET SUVR was -0·71 SUVR (95% CI -0·88 to -0·53, p<0·0001). Amyloid-related imaging abnormalities occurred in 53% (39 of 73) of participants: 47% (34 of 73) with microhaemorrhages, 30% (22 of 73) with oedema, and 6% (five of 73) were associated with superficial siderosis. No treatment-associated macrohaemorrhages or deaths occurred.

INTERPRETATION

Partial or short-term amyloid removal did not show significant clinical effects. However, long-term full amyloid removal potentially delayed symptom onset and dementia progression. Our conclusions are limited due to the OLE design and use of external controls and need to be confirmed in long-term trials.

FUNDING

National Institute on Aging, Alzheimer's Association, GHR Foundation, and F Hoffmann-La Roche/Genentech.

Safety and efficacy of long-term gantenerumab treatment in dominantly inherited Alzheimer's disease: an open label extension of the phase 2/3 multicentre, randomised, double-blind, placebo-controlled platform DIAN-TU Trial

Background

Amyloid-plaque removal by monoclonal antibody therapies slows clinical progression in symptomatic Alzheimer's disease; however, the potential for delaying the onset of clinical symptoms in asymptomatic people is unknown. The Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU) is an ongoing platform trial assessing the safety and efficacy of multiple investigational products in participants with dominantly inherited Alzheimer's disease (DIAD) caused by mutations. On the basis of findings of amyloid removal and downstream biological effects from the gantenerumab arm of the platform trial, we continued a 3-year open-label extension (OLE) study to assess the safety and efficacy of long-term treatment with high doses of gantenerumab.

Methods

The randomised, placebo-controlled, double-blind, phase 2/3 multi-arm trial (DIAN-TU-001) assessed solanezumab or gantenerumab versus placebo in participants who were between 15 years before to 10 years after their estimated years to symptom onset and had a Clinical Dementia Rating (CDR) global score of 0 (cognitively normal) to 1 (mild dementia). This study was followed by an OLE study of gantenerumab treatment, conducted at 18 study sites in Australia, Canada, France, Ireland, Puerto Rico, Spain, the UK, and USA. For inclusion in the OLE, participants at risk for DIAD had participated in the double-blind period of DIAN-TU-001 and were required to know their mutation status. We investigated increasing doses of gantenerumab up to 1500 mg subcutaneous every 2 weeks. Due to the lack of a regulatory path for gantenerumab, the study was stopped early after a pre-specified interim analysis (when most participants had completed 2 years of treatment) of the clinical measure CDR-SB. The primary outcome for the final analysis was the amyloid plaque measure PiB-PET SUVR at 3 years, assessed in the modified intention to treat population (defined as participants who received any gantenerumab treatment post-OLE baseline, had at least one PiB-PET SUVR assessment prior to gantenerumab treatment, and a post-baseline assessment). All participants who received at least one dose of study drug in the OLE were included in the safety analysis. DIAN-TU-001 (NCT01760005) and the OLE (NCT06424236) are registered with clinicaltrials.gov.

Findings

Of 74 participants who were recruited into the OLE study between June 3, 2020 and April 22, 2021, 73 were enrolled and received gantenerumab treatment. 47 (64%) stopped dosing due to early termination of the study by the sponsor, and 13 (18%) prematurely discontinued the study for other reasons. The mITT population for the primary analysis comprised 55 participants. At the interim analysis, the hazard ratio for clinical decline of CDR-SB in asymptomatic mutation carriers was 0.79 (n=53, 95% CI 0.47 to 1.32) for participants who were treated with gantenerumab in either the double-blind or OLE period (Any Gant), and 0.53 (n=22, 0.27 to 1.03) for participants who were treated with gantenerumab the longest (Longest Gant). At the final analysis, the adjusted mean change from OLE baseline to year 3 in PiB-PET SUVR was -0.71 SUVR (95% CI -0.88 to -0.53, p<0.0001). Amyloid-related imaging abnormalities occurred in 53% (39/73) of participants: 47% (34/73) with microhaemorrhages, 30% (22/73) with oedema, and 6% (5/73) were associated with symptoms. No treatment-associated macrohaemorrhages or deaths occurred.

Interpretation

Partial or short-term amyloid removal did not show significant clinical effects. However, long-term full amyloid removal potentially delayed symptom onset and dementia progression. Conclusions are limited due to the OLE design and use of external controls and need to be confirmed in long term trials.

Funding

National Institutes on Aging, Alzheimer's Association, GHR, F. Hoffmann-La Roche, Ltd/Genentech.

"Current and emerging drug therapies in Alzheimer's disease: A pathophysiological Perspective"

The analytical and experimental investigation of several targets and biomarkers that help in explaining significant cognitive deficits, covering drug development and precision medicine aimed at different chronic neurodegenerative conditions such as Alzheimer's disease (AD), Parkinson's disease, synaptic dysfunction, brain damage from neuronal apoptosis, and other disease pathologies; this served as the foundation for all phase studies. The focus of current therapeutic approaches is on developing humanized antibodies, agonist and antagonist drugs, receptors, signaling molecules, major targeted drug-metabolizing enzymes, and other metabolites to treat neurodegeneration in the AD brain brought on by tau hyperphosphorylation, amyloid plagues, or other cholinergic effects. The five A's-amnesia, agnosia, aphasia, apraxia, and anomia-are the typical symptoms associated with AD. While the main goal of drug therapeutics studies is modified amino acids acting as pro-drugs, pharmacokinetics studies and trends in evaluating drug-drug interactions focus on interactions between drugs and antibodies, drugs and therapeutic biologics like metabolites, herbs, interleukin-based, and gene silencing mechanism-based. Studies on the biotransformation of xenobiotic compounds and the metabolism of exogenous and endogenous substances are conducted under Phase I, Phase II, and Phase III trials because the pivotal pharmacokinetic properties of drugs, such as absorption, distribution, metabolism, and excretion (ADME), aid in understanding variations in the crucial improvement of various target drugs. This review also highlights the developments in soon-to-be genetically created targeted medications that may serve as ground-breaking treatments for cholinergic illnesses in the brains of AD patients and other neurodegenerative conditions.

Vascular Neurology Considerations for Antiamyloid Immunotherapy: A Science Advisory From the American Heart Association

Antibodies directed at the amyloid-β peptide offer the prospect of disease-modifying therapy for early-stage Alzheimer disease but also carry the risk of brain edema or bleeding events, collectively designated amyloid-related imaging abnormalities. Introduction of the antiamyloid immunotherapies into practice is therefore likely to present a new set of questions for clinicians treating patients with cerebrovascular disease: Which manifestations of cerebrovascular disease should preclude, or permit, antibody treatment? Is it safe to prescribe amyloid immunotherapies to individuals who require antithrombotic treatment, or to administer thrombolysis to antibody-treated individuals with acute stroke? How should severe amyloid-related imaging abnormalities be managed? This science advisory summarizes the data and key considerations to guide these challenging decisions as the medical community collects further data and experience with these groundbreaking agents.

Cholinergic System Structure and Function Changes in Individuals with Down Syndrome During the Development of Alzheimer's Disease

Adults with Down syndrome represent the population with the highest risk of developing Alzheimer's disease worldwide. The cholinergic system is known to decline in Alzheimer's disease, with this decline responsible for many of the cognitive deficits that develop. The integrity of the cholinergic system across the lifespan in individuals with Down syndrome is not well characterized. Small fetal and infant post-mortem studies suggest an intact cholinergic projection system with a potential reduction in cholinergic receptors, while post-mortem studies in adults with Down syndrome reveal an age-related decrease in cholinergic integrity. Advances in magnetic resonance imaging (MRI) and positron emission tomography (PET) over the last 20 years have allowed for studies investigating the changes in cholinergic integrity across aging and during the development of Alzheimer's disease. One large cross-sectional study demonstrated reduced cholinergic basal forebrain volume measured by MRI associated with increasing Alzheimer's disease pathology. In a small cohort of adults with Down syndrome, we have recently reported that PET measures of cholinergic integrity negatively correlated with amyloid accumulation. New disease-modifying treatments for Alzheimer's disease and treatments under development for Alzheimer's disease in Down syndrome have the potential to preserve the cholinergic system, while treatments targeting the cholinergic system directly may be used in conjunction with disease-modifying therapies to improve cognitive function further. A greater understanding of cholinergic neuronal and receptor integrity across the lifespan in individuals with Down syndrome will provide insights as to when targeting the cholinergic system is an appropriate therapeutic option and, in the future, maybe a valuable screening tool to identify individuals that would most benefit from cholinergic interventions.

Brain volume change following anti-amyloid β immunotherapy for Alzheimer's disease: amyloid-removal-related pseudo-atrophy

Progressive cerebral volume loss on MRI is a hallmark of Alzheimer's disease and has been widely used as an outcome measure in clinical trials, with the prediction that disease-modifying treatments would slow loss. However, in trials of anti-amyloid immunotherapy, the participants who received treatment had excess volume loss. Explanations for this observation range from reduction of amyloid β plaque burden and related inflammatory changes through to treatment-induced toxicity. The excess volume changes are characteristic of only those immunotherapies that achieve amyloid β lowering; are compatible with plaque removal; and evidence to date does not suggest an association with harmful effects. Based on the current evidence, we suggest that these changes can be described as amyloid-removal-related pseudo-atrophy. Better understanding of the causes and consequences of these changes is important to enable informed decisions about treatments. Patient-level analyses of data from the trials are urgently needed, along with longitudinal follow-up and neuroimaging data, to determine the long-term trajectory of these volume changes and their clinical correlates. Post-mortem examination of cerebral tissue from treated patients and evaluation of potential correlation with antemortem neuroimaging findings are key priorities.

Immunotherapy in Alzheimer's disease: focusing on the efficacy of gantenerumab on amyloid-β clearance and cognitive decline

Gantenerumab, a human monoclonal antibody (mAb), has been thought of as a potential agent to treat Alzheimer's disease (AD) by specifically targeting regions of the amyloid-β (Aβ) peptide sequence. Aβ protein accumulation in the brain leads to amyloid plaques, causing neuroinflammation, oxidative stress, neuronal damage, and neurotransmitter dysfunction, thereby causing cognitive decline in AD. Gantenerumab involves disrupting Aβ aggregation and promoting the breakdown of larger Aβ aggregates into smaller fragments, which facilitates the action of Aβ-degrading enzymes in the brain, thus slowing down the progression of AD. Moreover, Gantenerumab acts as an opsonin, coating Aβ plaques and enhancing their recognition by immune cells, which, combined with its ability to improve the activity of microglia, makes it an intriguing candidate for promoting Aβ plaque clearance. Indeed, the multifaceted effects of Gantenerumab, including Aβ disaggregation, enhanced immune recognition, and improved microglia activity, may position it as a promising therapeutic approach for AD. Of note, reports suggest that Gantenerumab, albeit its capacity to reduce or eliminate Aβ, has not demonstrated effectiveness in reducing cognitive decline. This review, after providing an overview of immunotherapy approaches that target Aβ in AD, explores the efficacy of Gantenerumab in reducing Aβ levels and cognitive decline.

Lecanemab demonstrates highly selective binding to Aβ protofibrils isolated from Alzheimer's disease brains

Recent advances in immunotherapeutic approaches to the treatment of Alzheimer's disease (AD) have increased the importance of understanding the exact binding preference of each amyloid-beta (Aβ) antibody employed, since this determines both efficacy and risk for potentially serious adverse events known as amyloid-related imaging abnormalities. Lecanemab is a humanized IgG1 antibody that was developed to target the soluble Aβ protofibril conformation. The present study prepared extracts of post mortem brain samples from AD patients and non-demented elderly controls, characterized the forms of Aβ present, and investigated their interactions with lecanemab. Brain tissue samples were homogenized and extracted using tris-buffered saline. Aβ levels and aggregation states in soluble and insoluble extracts, and in fractions prepared using size-exclusion chromatography or density gradient ultracentrifugation, were analyzed using combinations of immunoassay, immunoprecipitation (IP), and mass spectrometry. Lecanemab immunohistochemistry was also conducted in temporal cortex. The majority of temporal cortex Aβ (98 %) was in the insoluble extract. Aβ42 was the most abundant form present, particularly in AD subjects, and most soluble Aβ42 was in soluble aggregated protofibrillar structures. Aβ protofibril levels were much higher in AD subjects than in controls. Protofibrils captured by lecanemab-IP contained high levels of Aβ42 and lecanemab bound to large, medium, and small Aβ42 protofibrils in a concentration-dependent manner. Competitive IP showed that neither Aβ40 monomers nor Aβ40-enriched fibrils isolated from cerebral amyloid angiopathy reduced lecanemab's binding to Aβ42 protofibrils. Immunohistochemistry showed that lecanemab bound readily to Aβ plaques (diffuse and compact) and to intraneuronal Aβ in AD temporal cortex. Taken together, these findings indicate that while lecanemab binds to Aβ plaques, it preferentially targets soluble aggregated Aβ protofibrils. These are largely composed of Aβ42, and lecanemab binds less readily to the Aβ40-enriched fibrils found in the cerebral vasculature. This is a promising binding profile because Aβ42 protofibrils represent a key therapeutic target in AD, while a lack of binding to monomeric Aβ and cerebral amyloid deposits should reduce peripheral antibody sequestration and minimize risk for adverse events.

Advancements in dementia research, diagnostics, and care in Latin America: Highlights from the 2023 Alzheimer's Association International conference satellite symposium in Mexico City

INTRODUCTION

While Latin America (LatAm) is facing an increasing burden of dementia due to the rapid aging of the population, it remains underrepresented in dementia research, diagnostics, and care.

METHODS

In 2023, the Alzheimer's Association hosted its eighth satellite symposium in Mexico, highlighting emerging dementia research, priorities, and challenges within LatAm.

RESULTS

Significant initiatives in the region, including intracountry support, showcased their efforts in fostering national and international collaborations; genetic studies unveiled the unique genetic admixture in LatAm; researchers conducting emerging clinical trials discussed ongoing culturally specific interventions; and the urgent need to harmonize practices and studies, improve diagnosis and care, and use affordable biomarkers in the region was highlighted.

DISCUSSION

The myriad of topics discussed at the 2023 AAIC satellite symposium highlighted the growing research efforts in LatAm, providing valuable insights into dementia biology, genetics, epidemiology, treatment, and care.

Passive Anti-Amyloid Beta Immunotherapies in Alzheimer's Disease: From Mechanisms to Therapeutic Impact

Alzheimer's disease, the most common type of dementia worldwide, lacks effective disease-modifying therapies despite significant research efforts. Passive anti-amyloid immunotherapies represent a promising avenue for Alzheimer's disease treatment by targeting the amyloid-beta peptide, a key pathological hallmark of the disease. This approach utilizes monoclonal antibodies designed to specifically bind amyloid beta, facilitating its clearance from the brain. This review offers an original and critical analysis of anti-amyloid immunotherapies by exploring several aspects. Firstly, the mechanisms of action of these therapies are reviewed, focusing on their ability to promote Aβ degradation and enhance its efflux from the central nervous system. Subsequently, the extensive history of clinical trials involving anti-amyloid antibodies is presented, from initial efforts using first-generation molecules leading to mixed results to recent clinically approved drugs. Along with undeniable progress, the authors also highlight the pitfalls of this approach to offer a balanced perspective on this topic. Finally, based on its potential and limitations, the future directions of this promising therapeutic strategy for Alzheimer's disease are emphasized.

Amyloid-beta antibody binding to cerebral amyloid angiopathy fibrils and risk for amyloid-related imaging abnormalities

Therapeutic antibodies have been developed to target amyloid-beta (Aβ), and some of these slow the progression of Alzheimer's disease (AD). However, they can also cause adverse events known as amyloid-related imaging abnormalities with edema (ARIA-E). We investigated therapeutic Aβ antibody binding to cerebral amyloid angiopathy (CAA) fibrils isolated from human leptomeningeal tissue to study whether this related to the ARIA-E frequencies previously reported by clinical trials. The binding of Aβ antibodies to CAA Aβ fibrils was evaluated in vitro using immunoprecipitation, surface plasmon resonance, and direct binding assay. Marked differences in Aβ antibody binding to CAA fibrils were observed. Solanezumab and crenezumab showed negligible CAA fibril binding and these antibodies have no reported ARIA-E cases. Lecanemab showed a low binding to CAA fibrils, consistent with its relatively low ARIA-E frequency of 12.6%, while aducanumab, bapineuzumab, and gantenerumab all showed higher binding to CAA fibrils and substantially higher ARIA-E frequencies (25-35%). An ARIA-E frequency of 24% was reported for donanemab, and its binding to CAA fibrils correlated with the amount of pyroglutamate-modified Aβ present. The findings of this study support the proposal that Aβ antibody-CAA interactions may relate to the ARIA-E frequency observed in patients treated with Aβ-based immunotherapies.

Presenilin-1 mutation position influences amyloidosis, small vessel disease, and dementia with disease stage

INTRODUCTION

Amyloidosis, including cerebral amyloid angiopathy, and markers of small vessel disease (SVD) vary across dominantly inherited Alzheimer's disease (DIAD) presenilin-1 (PSEN1) mutation carriers. We investigated how mutation position relative to codon 200 (pre-/postcodon 200) influences these pathologic features and dementia at different stages.

METHODS

Individuals from families with known PSEN1 mutations (n = 393) underwent neuroimaging and clinical assessments. We cross-sectionally evaluated regional Pittsburgh compound B-positron emission tomography uptake, magnetic resonance imaging markers of SVD (diffusion tensor imaging-based white matter injury, white matter hyperintensity volumes, and microhemorrhages), and cognition.

RESULTS

Postcodon 200 carriers had lower amyloid burden in all regions but worse markers of SVD and worse Clinical Dementia Rating® scores compared to precodon 200 carriers as a function of estimated years to symptom onset. Markers of SVD partially mediated the mutation position effects on clinical measures.

DISCUSSION

We demonstrated the genotypic variability behind spatiotemporal amyloidosis, SVD, and clinical presentation in DIAD, which may inform patient prognosis and clinical trials.

HIGHLIGHTS

Mutation position influences Aβ burden, SVD, and dementia. PSEN1 pre-200 group had stronger associations between Aβ burden and disease stage. PSEN1 post-200 group had stronger associations between SVD markers and disease stage. PSEN1 post-200 group had worse dementia score than pre-200 in late disease stage. Diffusion tensor imaging-based SVD markers mediated mutation position effects on dementia in the late stage.

Cell subtype-specific effects of genetic variation in the Alzheimer's disease brain

The relationship between genetic variation and gene expression in brain cell types and subtypes remains understudied. Here, we generated single-nucleus RNA sequencing data from the neocortex of 424 individuals of advanced age; we assessed the effect of genetic variants on RNA expression in cis (cis-expression quantitative trait loci) for seven cell types and 64 cell subtypes using 1.5 million transcriptomes. This effort identified 10,004 eGenes at the cell type level and 8,099 eGenes at the cell subtype level. Many eGenes are only detected within cell subtypes. A new variant influences APOE expression only in microglia and is associated with greater cerebral amyloid angiopathy but not Alzheimer's disease pathology, after adjusting for APOEε4, providing mechanistic insights into both pathologies. Furthermore, only a TMEM106B variant affects the proportion of cell subtypes. Integration of these results with genome-wide association studies highlighted the targeted cell type and probable causal gene within Alzheimer's disease, schizophrenia, educational attainment and Parkinson's disease loci.

The Impact of Anti-Amyloid Immunotherapies on Stroke Care

Anti-amyloid immunotherapies have recently emerged as treatments for Alzheimer's disease. While these therapies have demonstrated efficacy in clearing amyloid-β and slowing cognitive decline, they have also been associated with amyloid-related imaging abnormalities (ARIA) which include both edema (ARIA-E) and hemorrhage (ARIA-H). Given that ARIA have been associated with significant morbidity in cases of antithrombotic or thrombolytic therapy, an understanding of mechanisms of and risk factors for ARIA is of critical importance for stroke care. We discuss the latest data regarding mechanisms of ARIA, including the role of underlying cerebral amyloid angiopathy, and implications for ischemic stroke prevention and management.

Risk factors in developing amyloid related imaging abnormalities (ARIA) and clinical implications

Alzheimer's disease (AD) affects over 6 million people over the age of 65. The advent of new anti-amyloid monoclonal antibodies as treatment for early Alzheimer's disease these immunotherapeutics may slow disease progression but also pose significant risks. Amyloid related imaging abnormalities (ARIA) identified on MRI following administration of these new monoclonal antibodies can cause both brain edema (ARIA-E) and hemorrhage (ARIA-H). While most ARIA is asymptomatic, some patients can develop headache, confusion, nausea, dizziness, seizures and in rare cases death. By analyzing lecanemab, aducanumab, gantenerumab, donanemab, and bapineuzumab clinical trials; risk factors for developing ARIA can be identified to mitigate some of the ARIA risk. Risk factors for developing ARIA-E are a positive Apoε4 carrier status and prior multiple cerebral microhemorrhages. Risk factors for ARIA-H are age, antithrombotic use, and history of prior strokes. With lecanemab, ARIA-E and ARIA-H were seen at lower rates 12 and 17%, respectively, compared to aducanumab (ARIA-E 35% and ARIA-H 19%) in treated patients. ARIA risk factors have impacted inclusion and exclusion criteria, determining who can receive lecanemab. In some clinics, almost 90% of Alzheimer's patients are excluded from receiving these new anti-amyloid therapeutics. This review aims to discuss risk factors of ARIA and highlight important areas for further research. With more anti-amyloid monoclonal antibodies approved by the Food and Drug Administration, considering patient risk factors for developing ARIA is important to identify to minimize patient's risk while receiving these new therapies.

Anti-Amyloid Monoclonal Antibodies for the Treatment of Alzheimer's Disease

Two monoclonal antibodies (mAbs), aducanumab and lecanemab, have received accelerated approval from the US FDA for initiation of treatment in early Alzheimer's disease patients who have proven β-amyloid pathology (Aβ). One of these, lecanemab, has subsequently received full approval and other monoclonal antibodies are poised for positive review and approval. Anti-amyloid mAbs share the feature of producing a marked reduction in total brain Aβ revealed by amyloid positron emission tomography. Trials associated with slowing of cognitive decline have achieved a reduction in measurable plaque Aβ in the range of 15-25 centiloids; trials of agents that did not reach this threshold were not associated with cognitive benefit. mAbs have differences in terms of titration schedules, MRI monitoring schedules for amyloid-related imaging abnormalities (ARIA), and continuing versus interrupted therapy. The approximate 30% slowing of decline observed with mAbs is clinically meaningful in terms of extended cognitive integrity and delay of onset of the more severe dementia phases of Alzheimer's disease. Approval of these agents initiates a new era in Alzheimer's disease therapeutics with disease-modifying properties. Further advances are needed, i.e. greater efficacy, improved safety, enhanced convenience, and better understanding of ill-understood observations such as brain volume loss.

Amyloid-Directed Antibodies: Past, Present, and Future

Background

Alzheimer's disease (AD) is the most common neurodegenerative disorder in patient demographics over 65 years old causing debilitating cognitive impairment. Most commonly, AD is diagnosed clinically as "probable AD", and definitive diagnosis is confirmed through postmortem brain autopsies to detect extracellular amyloid-β (Aβ) plaques and intraneuronal hyperphosphorylated tau tangles. The exact mechanism causing AD is still unknown, but treatments for AD have been actively investigated. Currently, immunotherapies have shown substantial promise in reducing the pathologic and clinical signs of AD.

Objective

This review aims to evaluate passive immunotherapies deemed to have promise for further development and use in the treatment of AD.

Methods

Immunotherapies were selected via a narrative review of medications that have potential clinical effectiveness with a status of FDA accepted, FDA fast-track, FDA status pending, or emerging therapies poised to pursue FDA approval.

Results

This review has yielded two anti-Aβ monoclonal antibodies (mAb) that are currently fully FDA approved, one mAb granted FDA fast-track status, two therapies on hold, three discontinued medications, and three promising emerging therapies.

Conclusions

We conclude that, in the near future, passive immunotherapies will be the preferred and evidence-based method of treatment for AD with the presence of brain Aβ deposits for both symptom management and potential slowing of disease progression. Specifically, lecanemab and donanemab will require further clinical studies to optimize patient selection based on safety profiles. Despite some key limitations, these two drugs are paving the way for disease-modifying treatments in patients displaying early signs of amyloid pathology.

Emerging diagnostics and therapeutics for Alzheimer disease

Alzheimer disease (AD) is the most common contributor to dementia in the world, but strategies that slow or prevent its clinical progression have largely remained elusive, until recently. This Review highlights the latest advances in biomarker technologies and therapeutic development to improve AD diagnosis and treatment. We review recent results that enable pathological staging of AD with neuroimaging and fluid-based biomarkers, with a particular emphasis on the role of amyloid, tau and neuroinflammation in disease pathogenesis. We discuss the lessons learned from randomized controlled trials, including some supporting the proposal that certain anti-amyloid antibodies slow cognitive decline during the mildly symptomatic phase of AD. In addition, we highlight evidence for newly identified therapeutic targets that may be able to modify AD pathogenesis and progression. Collectively, these recent discoveries-and the research directions that they open-have the potential to move AD clinical care toward disease-modifying treatment strategies with maximal benefits for patients.

Does acupuncture have advantages in the rehabilitation of vascular mild cognitive impairment? A systematic review and meta-analysis

Background

Vascular mild cognitive impairment (VMCI) is a common impairment caused by vascular factors. VMCI often occurs after stroke, and it is the main clinical manifestation of long-term disability. Many patients are treated with acupuncture in combination with other therapies. However, evidence regarding the effectiveness of this treatment regimen is lacking.

Aims

This meta-analysis aimed to evaluate the efficacy of acupuncture therapy for treating VMCI.

Methods

This systematic review was conducted in accordance with the preferred reporting and meta-analysis guidelines. The CNKI, Wanfang, VIP, CBM, Cochrane Library, PubMed and Embase databases were searched from inception to August 20, 2022. After two researchers independently screened the literature, they extracted the data and evaluated the risk of bias in the included studies. Revman 5.3 software was used for the meta-analysis.

Summary of review

Thirty-two randomized controlled trials (RCTs) were included. The overall effective rate of acupuncture for treating VMCI was 3.06, 95% CI [2.39, 3.91], (P < 0.05). Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Barthel Index and Activities of Daily Living (ADLs) scores significantly differed between the treatment and control groups, with weighted mean differences (WMDs) [95% CI] (P value) of 1.97 [1.44, 2.49] (P < 0.05), 2.02 [1.50, 2.54] (P < 0.05), 5.54 [3.81, 7.28] (P < 0.05), and 3.43 [2.53, 4.33] (P < 0.05), respectively. The overall effective rate of electroacupuncture (EA) for treating VMCI was better than that of the control group (RR = 2.25, 95% CI, [1.13, 4.50], P < 0.05). MoCA, MMSE, Barthel index and ADL scores differed significantly between the treatment and control groups, with WMDs [95% CI] (P value) of 1.79 [1.20, 2.38] (P < 0.05), 1.45 [0.87, 2.03] (P < 0.05), 5.78 [2.38, 9.18] (P < 0.05), and 3.15 [2.15, 4.15] (P < 0.05), respectively. Acupuncture alone and combined with drug therapy were thus superior to drug therapy alone for improving cognitive function. EA also has potential advantages.

Conclusions

Acupuncture combined with another therapy is better than other therapies alone, such as simple drug therapy, for treating VMCI. However, variations in study duration (4-12 weeks) limit us from drawing any definitive conclusions about long-term effects. Therefore, more RCTs with rigorous designs and reasonable treatment and follow-up durations are needed.