Dementia with Lewy Bodies Drug Therapies in Clinical Trials: Systematic Review up to 2022

Neuropsychological test performance in mild cognitive impairment with Lewy bodies: A systematic review and meta-analysis

BACKGROUND

We sought to characterize the cognitive profile among individuals with mild cognitive impairment with Lewy bodies (MCI-LB) to help guide future clinical criteria.

METHODS

Systematic review and meta-analysis included MCI-LB studies with cognitive data from PubMed, Embase, Web of Science, and PsycINFO (January 1990 to March 2023). MCI-LB scores were compared to controls, MCI due to Alzheimer's disease (MCI-AD), and dementia with Lewy bodies (DLB) groups with random-effects models.

RESULTS

We included 26 studies and 2823 participants. Across all domains, the MCI-LB group performed worse than controls and better than DLB. Compared to MCI-AD, the MCI-LB group performed worse in attention/processing speed (g = -0.24, 95% confidence interval [CI]: -0.35, -0.12), attention/executive (g = -0.42, 95% CI: -0.56, -0.28); better in verbal immediate recall (g = 0.37; 95% CI: 0.15, 0.59) and delayed memory (g = 0.40; 95% CI: 0.22, 0.58).

DISCUSSION

The cognitive profiles in MCI-LB and MCI-AD are consistent with established profiles in DLB and AD. Neuropsychological assessment may be helpful in differential diagnosis, even in early disease states.

HIGHLIGHTS

We performed a systematic review and meta-analysis for cognition in mild cognitive impairment with Lewy bodies (MCI-LB). Compared to MCI due to Alzheimer's disease (MCI-AD), MCI-LB had worse attention, executive function, and processing speed. Compared to MCI-AD, MCI-LB had better verbal immediate and delayed recall. The MCI-LB group was worse on all cognitive domains than controls, and better than dementia with Lewy bodies. Studies used different tests and there is a need for global efforts for harmonization.

What is the future for dementia with Lewy bodies?

Dementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia after Alzheimer's disease (AD), yet it remains under-recognized and frequently misdiagnosed due to heterogenous clinical presentations, the presence of co-pathology, and the lack of specific diagnostic tools. Pathologically, DLB is characterized by the accumulation of misfolded alpha-synuclein (aSyn) aggregates, known as Lewy bodies. Recent advancements have improved in vivo detection of aSyn pathology through techniques such as seed amplification assays, monoclonal antibodies, and positron emission tomography using novel small-molecule ligands. The ability to detect aSyn in vivo has sparked dialogue about using biomarkers to identify individuals with aSyn, similar to the approach influencing the field of AD. Proponents argue that biological staging could facilitate the detection of preclinical disease stages, allowing for earlier intervention and targets for disease modification, and could improve diagnostic sensitivity and accuracy in selecting patients for clinical trials. However, critics caution that this method may oversimplify the complexity of DLB and overlook its clinical heterogeneity, also highlighting practical challenges related to implementation, cost, and global access to advanced diagnostic technologies. Importantly, although significant progress has been made in detecting aSyn for diagnostic purposes, disease-modifying therapies targeting aSyn have yet to demonstrate clear efficacy in slowing disease progression. Elucidating the physiological and pathophysiological roles of aSyn remains an urgent priority in neurodegenerative research. Other experimental research priorities for DLB include developing improved cellular and animal models that reflect epigenetic and environmental factors, mapping post-translational modifications, and systematically characterizing neurons that are vulnerable and resistant to lewy pathology using a multi-omic approach. Clinically, there is an urgent need for international, prospective, longitudinal studies and for validated, disease-specific outcome measures. Addressing these priorities is essential for advancing our understanding of DLB and developing effective therapies.

The Parkinson's Disease Composite of Executive Functioning: A Measure for Detecting Cognitive Decline in Clinical Trials

BACKGROUND AND OBJECTIVES

Executive functioning is one of the first domains to be impaired in Parkinson disease (PD), and the majority of patients with PD eventually develop dementia. Thus, developing a cognitive endpoint measure specifically assessing executive functioning is critical for PD clinical trials. The objective of this study was to develop a cognitive composite measure that is sensitive to decline in executive functioning for use in PD clinical trials.

METHODS

We used cross-sectional and longitudinal follow-up data from PD participants enrolled in the PD Cognitive Genetics Consortium, a multicenter setting focused on PD. All PD participants with Trail Making Test, Digit Symbol, Letter-Number Sequencing, Semantic Fluency, and Phonemic Fluency neuropsychological data collected from March 2010 to February 2020 were included. Baseline executive functioning data were used to create the Parkinson's Disease Composite of Executive Functioning (PaCEF) through confirmatory factor analysis. We examined the changes in the PaCEF over time, how well baseline PaCEF predicts time to cognitive progression, and the required sample size estimates for PD clinical trials. PaCEF results were compared with the Montreal Cognitive Assessment (MoCA), individual tests forming the PaCEF, and tests of visuospatial, language, and memory functioning.

RESULTS

A total of 841 participants (251 no cognitive impairment [NCI], 480 mild cognitive impairment [MCI], and 110 dementia) with baseline data were included, of which the mean (SD) age was 67.1 (8.9) years and 270 were women (32%). Five hundred forty five PD participants had longitudinal neuropsychological data spanning 9 years (mean [SD] 4.5 [2.2] years) and were included in analyses examining cognitive decline. A 1-factor model of executive functioning with excellent fit (comparative fit index = 0.993, Tucker-Lewis index = 0.989, and root mean square error of approximation = 0.044) was used to calculate the PaCEF. The average annual change in PaCEF ranged from 0.246 points per year for PD-NCI participants who remained cognitively unimpaired to -0.821 points per year for PD-MCI participants who progressed to dementia. For PD-MCI, baseline PaCEF, but not baseline MoCA, significantly predicted time to dementia. Sample size estimates were 69%-73% smaller for PD-NCI trials and 16%-19% smaller for PD-MCI trials when using the PaCEF rather than MoCA as the endpoint.

DISCUSSION

The PaCEF is a sensitive measure of executive functioning decline in PD and will be especially beneficial for PD clinical trials.

Plasma biomarkers of amyloid, tau, axonal, and neuroinflammation pathologies in dementia with Lewy bodies

BACKGROUND

Increasing evidence supports the use of plasma biomarkers of amyloid, tau, neurodegeneration, and neuroinflammation for diagnosis of dementia. However, their performance for positive and differential diagnosis of dementia with Lewy bodies (DLB) in clinical settings is still uncertain.

METHODS

We conducted a retrospective biomarker study in two tertiary memory centers, Paris Lariboisière and CM2RR Strasbourg, France, enrolling patients with DLB (n = 104), Alzheimer's disease (AD, n = 76), and neurological controls (NC, n = 27). Measured biomarkers included plasma Aβ40/Aβ42 ratio, p-tau181, NfL, and GFAP using SIMOA and plasma YKL-40 and sTREM2 using ELISA. DLB patients with available CSF analysis (n = 90) were stratified according to their CSF Aβ profile.

RESULTS

DLB patients displayed modified plasma Aβ ratio, p-tau181, and GFAP levels compared with NC and modified plasma Aβ ratio, p-tau181, GFAP, NfL, and sTREM2 levels compared with AD patients. Plasma p-tau181 best differentiated DLB from AD patients (ROC analysis, area under the curve [AUC] = 0.80) and NC (AUC = 0.78), and combining biomarkers did not improve diagnosis performance. Plasma p-tau181 was the best standalone biomarker to differentiate amyloid-positive from amyloid-negative DLB cases (AUC = 0.75) and was associated with cognitive status in the DLB group. Combining plasma Aβ ratio, p-tau181 and NfL increased performance to identify amyloid copathology (AUC = 0.79). Principal component analysis identified different segregation patterns of biomarkers in the DLB and AD groups.

CONCLUSIONS

Amyloid, tau, neurodegeneration and neuroinflammation plasma biomarkers are modified in DLB, albeit with moderate diagnosis performance. Plasma p-tau181 can contribute to identify Aβ copathology in DLB.

Clinically feasible automated MRI volumetry of the brain as a prognostic marker in subjective and mild cognitive impairment

Background/aims

The number of patients suffering from cognitive decline and dementia increases, and new possible treatments are being developed. Thus, the need for time efficient and cost-effective methods to facilitate an early diagnosis and prediction of future cognitive decline in patients with early cognitive symptoms is becoming increasingly important. The aim of this study was to evaluate whether an MRI based software, NeuroQuant® (NQ), producing volumetry of the hippocampus and whole brain volume (WBV) could predict: (1) conversion from subjective cognitive decline (SCD) at baseline to mild cognitive impairment (MCI) or dementia at follow-up, and from MCI at baseline to dementia at follow-up and (2) progression of cognitive and functional decline defined as an annual increase in the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) score.

Methods

MRI was performed in 156 patients with SCD or MCI from the memory clinic at Oslo University Hospital (OUH) that had been assessed with NQ and had a clinical follow-up examination. Logistic and linear regression analyses were performed with hippocampus volume and WBV as independent variables, and conversion or progression as dependent variables, adjusting for demographic and other relevant covariates including Mini-Mental State Examination-Norwegian Revised Version score (MMSE-NR) and Apolipoprotein E ɛ4 (APOE ɛ4) carrier status.

Results

Hippocampus volume, but not WBV, was associated with conversion to MCI or dementia, but neither were associated with conversion when adjusting for MMSE-NR. Both hippocampus volume and WBV were associated with progression as measured by the annual change in CDR-SB score in both unadjusted and adjusted analyses.

Conclusion

The results indicate that automated regional MRI volumetry of the hippocampus and WBV can be useful in predicting further cognitive decline in patients with early cognitive symptoms.

Targeting Lewy body dementia with neflamapimod-rasagiline hybrids

Lewy body dementia (LBD) represents the second most common neurodegenerative dementia but is a quite underexplored therapeutic area. Nepflamapimod (1) is a brain-penetrant selective inhibitor of the alpha isoform of the mitogen-activated serine/threonine protein kinase (MAPK) p38α, recently repurposed for LBD due to its remarkable antineuroinflammatory properties. Neuroprotective propargylamines are another class of molecules with a therapeutical potential against LBD. Herein, we sought to combine the antineuroinflammatory core of 1 and the neuroprotective propargylamine moiety into a single molecule. Particularly, we inserted a propargylamine moiety in position 4 of the 2,6-dichlorophenyl ring of 1, generating neflamapimod-propargylamine hybrids 3 and 4. These hybrids were evaluated using several cell models, aiming to recapitulate the complexity of LBD pathology through different molecular mechanisms. The N-methyl-N-propargyl derivative 4 showed a nanomolar p38α-MAPK inhibitory activity (IC50 = 98.7 nM), which is only 2.6-fold lower compared to that of the parent compound 1, while displaying no hepato- and neurotoxicity up to 25 μM concentration. It also retained a similar immunomodulatory profile against the N9 microglial cell line. Gratifyingly, at 5 μM concentration, 4 demonstrated a neuroprotective effect against dexamethasone-induced reactive oxygen species production in neuronal cells that was higher than that of 1.

LETC inhibits α-Syn aggregation and ameliorates motor deficiencies in the L62 mouse model of synucleinopathy

Alpha-Synuclein (α-Syn) aggregation is a pathological feature of synucleinopathies, neurodegenerative disorders that include Parkinson's disease (PD). Here, we explored the efficacy of N,N,N',N'-tetraethyl-10H-phenothiazine-3,7-diamine dihydrochloride (LETC), a protein aggregation inhibitor, on α-Syn aggregation. In both cellular models and transgenic mice, α-Syn aggregation was achieved by the overexpression of full-length human α-Syn fused with a signal sequence peptide. α-Syn accumulated in transfected DH60.21 neuroblastoma cells and α-Syn aggregation was inhibited by LETC with an EC50 of 0.066 ± 0.047 μM. Full-length human α-Syn overexpressing Line 62 (L62) mice accumulated neuronal α-Syn that was associated with a decreased motor performance in the open field and automated home cage. LETC, administered orally for 6 weeks at 10 mg/kg significantly decreased α-Syn-positive neurons in multiple brain regions and this resulted in a rescue of movement deficits in the open field in these mice. LETC however, did not improve activity deficits of L62 mice in the home cage environment. The results suggest that LETC may provide a potential disease modification therapy in synucleinopathies through the inhibition of α-Syn aggregation.

Meeting Summary of The NYO3 5th NO-Age/AD Meeting and the 1st Norway-UK Joint Meeting on Aging and Dementia: Recent Progress on the Mechanisms and Interventional Strategies

Unhealthy aging poses a global challenge with profound healthcare and socioeconomic implications. Slowing down the aging process offers a promising approach to reduce the burden of a number of age-related diseases, such as dementia, and promoting healthy longevity in the old population. In response to the challenge of the aging population and with a view to the future, Norway and the United Kingdom are fostering collaborations, supported by a "Money Follows Cooperation agreement" between the 2 nations. The inaugural Norway-UK joint meeting on aging and dementia gathered leading experts on aging and dementia from the 2 nations to share their latest discoveries in related fields. Since aging is an international challenge, and to foster collaborations, we also invited leading scholars from 11 additional countries to join this event. This report provides a summary of the conference, highlighting recent progress on molecular aging mechanisms, genetic risk factors, DNA damage and repair, mitophagy, autophagy, as well as progress on a series of clinical trials (eg, using NAD+ precursors). The meeting facilitated dialogue among policymakers, administrative leaders, researchers, and clinical experts, aiming to promote international research collaborations and to translate findings into clinical applications and interventions to advance healthy aging.

Lewy body dementia: Overcoming barriers and identifying solutions

Despite its high prevalence among dementias, Lewy body dementia (LBD) remains poorly understood with a limited, albeit growing, evidence base. The public-health burden that LBD imposes is worsened by overlapping pathologies, which contribute to misdiagnosis, and lack of treatments. For this report, we gathered and analyzed public-domain information on advocacy, funding, research outputs, and the therapeutic pipeline to identify gaps in each of these key elements. To further understand the current gaps, we also conducted interviews with leading experts in regulatory/governmental agencies, LBD advocacy, academic research, and biopharmaceutical research, as well as with funding sources. We identified wide gaps across the entire landscape, the most critical being in research. Many of the experts participated in a workshop to discuss the prioritization of research areas with a view to accelerating therapeutic development and improving patient care. This white paper outlines the opportunities for bridging the major LBD gaps and creates the framework for collaboration in that endeavor. HIGHLIGHTS: A group representing academia, government, industry, and consulting expertise was convened to discuss current progress in Dementia with Lewy Body care and research. Consideration of expert opinion,natural language processing of the literature as well as publicly available data bases, and Delphi inspired discussion led to a proposed consensus document of priorities for the field.