Safety and Tolerability of GRF6019 Infusions in Severe Alzheimer's Disease: A Phase II Double-Blind Placebo-Controlled Trial

Healthy blood, healthy brain: a window into understanding and treating neurodegenerative diseases

Our limited understanding of complex neurodegenerative disorders has held us back on the development of efficient therapies. While several approaches are currently being considered, it is still unclear what will be most successful. Among the latest and more novel ideas, the concept of blood or plasma transfusion from young healthy donors to diseased patients is gaining momentum and attracting attention beyond the scientific arena. While young or healthy blood is enriched with protective and restorative components, blood from older subjects may accumulate neurotoxic agents or be impoverished of beneficial factors. In this commentary, we present an overview of the compelling evidence collected in various animal models of brain diseases (e.g., Alzheimer, Parkinson, Huntington) to the actual clinical trials that have been conducted to test the validity of blood-related treatments in neurodegenerative diseases and argue in favor of such approach.

Blood-based therapies to combat neurodegenerative diseases

Neurodegeneration, known as the progressive loss of neurons in terms of their structure and function, is the principal pathophysiological change found in the majority of brain-related disorders. Ageing has been considered the most well-established risk factor in most common neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD). There is currently no effective treatment or cure for these diseases; the approved therapeutic options to date are only for palliative care. Ageing and neurodegenerative diseases are closely intertwined; reversing the aspects of brain ageing could theoretically mitigate age-related neurodegeneration. Ever since the regenerative properties of young blood on aged tissues came to light, substantial efforts have been focused on identifying and characterizing the circulating factors in the young and old systemic milieu that may attenuate or accentuate brain ageing and neurodegeneration. Later studies discovered the superiority of old plasma dilution in tissue rejuvenation, which is achieved through a molecular reset of the systemic proteome. These findings supported the use of therapeutic blood exchange for the treatment of degenerative diseases in older individuals. The first objective of this article is to explore the rejuvenating properties of blood-based therapies in the ageing brains and their therapeutic effects on AD. Then, we also look into the clinical applications, various limitations, and challenges associated with blood-based therapies for AD patients.

Immunological dimensions of neuroinflammation and microglial activation: exploring innovative immunomodulatory approaches to mitigate neuroinflammatory progression

The increasing life expectancy has led to a higher incidence of age-related neurodegenerative conditions. Within this framework, neuroinflammation emerges as a significant contributing factor. It involves the activation of microglia and astrocytes, leading to the release of pro-inflammatory cytokines and chemokines and the infiltration of peripheral leukocytes into the central nervous system (CNS). These instances result in neuronal damage and neurodegeneration through activated nucleotide-binding domain and leucine-rich repeat containing (NLR) family pyrin domain containing protein 3 (NLRP3) and nuclear factor kappa B (NF-kB) pathways and decreased nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Due to limited effectiveness regarding the inhibition of neuroinflammatory targets using conventional drugs, there is challenging growth in the search for innovative therapies for alleviating neuroinflammation in CNS diseases or even before their onset. Our results indicate that interventions focusing on Interleukin-Driven Immunomodulation, Chemokine (CXC) Receptor Signaling and Expression, Cold Exposure, and Fibrin-Targeted strategies significantly promise to mitigate neuroinflammatory processes. These approaches demonstrate potential anti-neuroinflammatory effects, addressing conditions such as Multiple Sclerosis, Experimental autoimmune encephalomyelitis, Parkinson's Disease, and Alzheimer's Disease. While the findings are promising, immunomodulatory therapies often face limitations due to Immune-Related Adverse Events. Therefore, the conduction of randomized clinical trials in this matter is mandatory, and will pave the way for a promising future in the development of new medicines with specific therapeutic targets.

Targeting synapse function and loss for treatment of neurodegenerative diseases

Synapse dysfunction and loss are hallmarks of neurodegenerative diseases that correlate with cognitive decline. However, the mechanisms and therapeutic strategies to prevent or reverse synaptic damage remain elusive. In this Review, we discuss recent advances in understanding the molecular and cellular pathways that impair synapses in neurodegenerative diseases, including the effects of protein aggregation and neuroinflammation. We also highlight emerging therapeutic approaches that aim to restore synaptic function and integrity, such as enhancing synaptic plasticity, preventing synaptotoxicity, modulating neuronal network activity and targeting immune signalling. We discuss the preclinical and clinical evidence for each strategy, as well as the challenges and opportunities for developing effective synapse-targeting therapeutics for neurodegenerative diseases.

Paradigm Shift: Multiple Potential Pathways to Neurodegenerative Dementia

Neurodegenerative dementia can result from multiple underlying abnormalities, including neurotransmitter imbalances, protein aggregation, and other neurotoxic events. A major complication in identifying effective treatment targets is the frequent co-occurrence of multiple neurodegenerative processes, occurring either in parallel or sequentially. The path towards developing effective treatments for Alzheimer's disease (AD) and other dementias has been relatively slow and until recently has focused on disease symptoms. Aducanumab and lecanemab, recently approved by the FDA, are meant to target disease structures but have only modest benefit on symptom progression and remain unproven in reversing or preventing dementia. A third, donanemab, appears more promising but awaits FDA approval. Ongoing trials include potential cognition enhancers, new combinations of known drugs for synergistic effects, prodrugs with less toxicity, and increasing interest in drugs targeting neuroinflammation or microbiome. Scientific and technological advances offer the opportunity to move in new therapy directions, such as modifying microglia to prevent or suppress underlying disease. A major challenge, however, is that underlying comorbidities likely influence the effectiveness of therapies. Indeed, the full range of comorbidity, today only definitively identified postmortem, likely contributes to failed clinical trials and overmedication of older adults, since it is difficult to exclude (during life) people unlikely to respond. Our current knowledge thus signals that a paradigm shift towards individualized and multimodal treatments is necessary to effectively advance the field of dementia therapeutics.

Synaptic degeneration in Alzheimer disease

Alzheimer disease (AD) is characterized by progressive cognitive decline in older individuals accompanied by the presence of two pathological protein aggregates - amyloid-β and phosphorylated tau - in the brain. The disease results in brain atrophy caused by neuronal loss and synapse degeneration. Synaptic loss strongly correlates with cognitive decline in both humans and animal models of AD. Indeed, evidence suggests that soluble forms of amyloid-β and tau can cause synaptotoxicity and spread through neural circuits. These pathological changes are accompanied by an altered phenotype in the glial cells of the brain - one hypothesis is that glia excessively ingest synapses and modulate the trans-synaptic spread of pathology. To date, effective therapies for the treatment or prevention of AD are lacking, but understanding how synaptic degeneration occurs will be essential for the development of new interventions. Here, we highlight the mechanisms through which synapses degenerate in the AD brain, and discuss key questions that still need to be answered. We also cover the ways in which our understanding of the mechanisms of synaptic degeneration is leading to new therapeutic approaches for AD.

Effectiveness of treatments for people living with severe dementia: A systematic review and meta-analysis of randomised controlled clinical trials

BACKGROUND

Dementia is a progressive neurodegenerative syndrome that has no cure. Although a significant proportion of people with dementia progress into the severe stages of the disease, evidence on the clinical effectiveness of treatments for people with severe dementia remains limited.

AIMS

To systematically review the effectiveness of pharmacological and non-pharmacological treatments for people living with severe dementia and assess the quality of the evidence.

METHOD

We searched MEDLINE, EMBASE, PsycINFO, CINAHL and online clinical trial registers up to January 2022, for Randomised Controlled Trials (RCT) in people living with severe dementia. Quality and risk of bias were assessed independently by two authors.

RESULTS

A total of 30 trials met our inclusion criteria of which 14 evaluated the effectiveness of pharmacological treatments, and 16 evaluated a non-pharmacological intervention. Pharmacological treatments: Meta-analyses indicated that pharmacological treatments (donepezil: 10 mg, 5 mg; galantamine: 24 mg; memantine: 10 mg) are associated with better outcomes compared to placebo for: severity of symptoms (standardized mean difference (SMD) 0.37, 95% CI 0.26-0.48; 4 studies; moderate-certainty evidence), activities of daily living (SMD 0.15, 95% CI 0.04-0.26; 5 studies; moderate-certainty evidence), and clinical impression of change (Relative Risk (RR) 1.34, 95% CI 1.14-1.57; 4 studies; low-certainty evidence). Pharmacological treatments were also more likely to reduce mortality compared to placebo (RR 0.60, 95% CI 0.40-0.89; 6 studies; low-certainty evidence). Non-pharmacological treatments: Five trials were included in the meta-analyses of non-pharmacological interventions (multi-sensory stimulation, needs assessment, and activities-based interventions); results showed that non-pharmacological interventions may reduce neuropsychiatric symptoms of dementia compared to usual care (SMD -0.33, 95% CI -0.59 to -0.06; low certainty evidence).

CONCLUSIONS

There is moderate-certainty evidence that pharmacological treatments may decrease disease severity and improve function for people with severe dementia. Non-pharmacological treatments are probably effective in reducing neuropsychiatric symptoms but the quality of evidence remains low. There is an urgent need for high-quality evidence for other outcomes and for developing service-user informed interventions for this under-served group.

Efficacy and safety of blood derivatives therapy in Alzheimer's disease: a systematic review and meta-analysis

BACKGROUND

Blood derivatives therapy is a conventional clinical treatment, while the treatment for Alzheimer's disease (AD) is relatively novel. To provide clinical references for treating AD, this meta-analysis was performed to evaluate the efficacy and safety of blood derivatives therapy on the patients with AD.

METHODS

A systematic articles search was performed for eligible studies published up to December 6, 2021 through the PubMed, Embase, Cochrane library, ClinicalTrials.gov , Chinese National Knowledge Infrastructure database, and Wanfang databases. The included articles were screened by using rigorous inclusion and exclusion criteria. Study selection and data-extraction were performed by two authors independently. Random effects model or fixed effects model was used. Quality of studies and risk of bias were evaluated according to the Cochrane risk of bias tool. All analyses were conducted using Review Manager 5.4. The study was designed and conducted according to the Preferring Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

RESULTS

A total of three plasma administrations (two plasma exchange and one young plasma infusion) and five intravenous immunoglobulin (IVIG) randomized controlled trials with a sample size of 1148 subjects diagnosed with AD were included. There was no significant difference in cognitive improvement and all-cause discontinuation between intervention and placebo groups (RR 1.10, 95% CI 0.79-1.54). And Intervention groups showed not a statistically significant improvement in cognition of included subjects measured by the ADAS-Cog (MD 0.36, 95% CI 0.87-1.59), ADCS-ADL (MD -1.34, 95% CI - 5.01-2.32) and NPI (MD 2.20, 95% CI 0.07-4.32) score compared to the control groups. IVIG is well tolerated for AD patients even under the maximum dose (0.4 g/kg), but it is inferior to placebo in Neuropsychiatric Inventory scale in AD patients (MD 2.19, 95% CI 0.02-4.37).

CONCLUSIONS

The benefits of blood derivatives therapy for AD are limited. It is necessary to perform well-designed randomized controlled trials with large sample sizes focusing on the appropriate blood derivatives for the specific AD sub-populations in the future.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021233886.

Symptomatic and Disease-Modifying Therapy Pipeline for Alzheimer’s Disease: Towards a Personalized Polypharmacology Patient-Centered Approach

Since 1906, when Dr. Alois Alzheimer first described in a patient “a peculiar severe disease process of the cerebral cortex”, people suffering from this pathology have been waiting for a breakthrough therapy. Alzheimer’s disease (AD) is an irreversible, progressive neurodegenerative brain disorder and the most common form of dementia in the elderly with a long presymptomatic phase. Worldwide, approximately 50 million people are living with dementia, with AD comprising 60–70% of cases. Pathologically, AD is characterized by the deposition of amyloid β-peptide (Aβ) in the neuropil (neuritic plaques) and blood vessels (amyloid angiopathy), and by the accumulation of hyperphosphorylated tau in neurons (neurofibrillary tangles) in the brain, with associated loss of synapses and neurons, together with glial activation, and neuroinflammation, resulting in cognitive deficits and eventually dementia. The current competitive landscape in AD consists of symptomatic treatments, of which there are currently six approved medications: three AChEIs (donepezil, rivastigmine, and galantamine), one NMDA-R antagonist (memantine), one combination therapy (memantine/donepezil), and GV-971 (sodium oligomannate, a mixture of oligosaccharides derived from algae) only approved in China. Improvements to the approved therapies, such as easier routes of administration and reduced dosing frequencies, along with the developments of new strategies and combined treatments are expected to occur within the next decade and will positively impact the way the disease is managed. Recently, Aducanumab, the first disease-modifying therapy (DMT) has been approved for AD, and several DMTs are in advanced stages of clinical development or regulatory review. Small molecules, mAbs, or multimodal strategies showing promise in animal studies have not confirmed that promise in the clinic (where small to moderate changes in clinical efficacy have been observed), and therefore, there is a significant unmet need for a better understanding of the AD pathogenesis and the exploration of alternative etiologies and therapeutic effective disease-modifying therapies strategies for AD. Therefore, a critical review of the disease-modifying therapy pipeline for Alzheimer’s disease is needed.

Out with the old, in with the new: Could plasma exchange be used to fill a therapeutic gap in neurology?

The global tally of neurological disorders is exponentially rising and yet effective therapies for most remain evasive. There is a great deal of research into novel small molecules, immunotherapies and gene therapies to fill this therapeutic gap. We believe greater focus on plasma exchange as a research and clinical tool may provide useful insight into pathological mechanisms and effective treatment strategies. Plasma exchange has been traditionally used to treat antibody-mediated neurological diseases, such as myasthenia gravis and neuromyelitis optica, but there could be much wider future potential uses in neurology. Plasma exchange is not antibody specific, as it also removes a variety of other plasma-soluble factors, including age-related and disease-associated neurotoxic proteins, such as fibrinogen and amyloid. As research develops into the role of blood-brain barrier and immunological alterations in diseases not typically regarded as immune-driven, interest in neurotoxic plasma proteins grows. Here, we highlight that plasma exchange may have uses outside of antibody-mediated neurological diseases, by removing neurotoxic proteins from the systemic circulation.