Citations

Children, adolescents, and young adults (CAYA) with relapsed/refractory classical Hodgkin lymphoma (cHL) without complete metabolic response (CMR) before autologous hematopoietic cell transplantation (auto-HCT) have poor survival outcomes. CheckMate 744, a phase 2 study for CAYA (aged 5-30 years) with relapsed/refractory cHL, evaluated a risk-stratified, response-adapted approach with nivolumab plus brentuximab vedotin (BV) followed by BV plus bendamustine for patients with suboptimal response. Risk stratification was primarily based on time to relapse, prior treatment, and presence of B symptoms. We present the primary analysis of the standard-risk cohort. Data from the low-risk cohort are reported separately. Patients received 4 induction cycles with nivolumab plus BV; those without CMR (Deauville score >3, Lugano 2014) received BV plus bendamustine intensification. Patients with CMR after induction or intensification proceeded to consolidation (high-dose chemotherapy/auto-HCT per protocol). Primary endpoint was CMR any time before consolidation. Forty-four patients were treated. Median age was 16 years. At a minimum follow-up of 15.6 months, 43 patients received 4 induction cycles (1 discontinued); 11 of whom received intensification, 32 proceeded to consolidation. CMR rate was 59% after induction with nivolumab plus BV, and 94% any time before consolidation (nivolumab plus BV ± BV plus bendamustine). One-year PFS rate was 91%. During induction, 18% of patients experienced grade 3/4 treatment-related adverse events. This risk-stratified, response-adapted salvage strategy had high CMR rates with limited toxicities in CAYA with relapsed/refractory cHL. Most patients did not require additional chemotherapy (bendamustine intensification). Additional follow-up is needed to confirm durability of disease control. ClinicalTrials.gov: NCT02927769.

AbstractBackgroundThere is a critical need for tau PET radiotracers that accurately detect non‐Alzheimer’s disease (AD) tau pathology. We aim to evaluate [18F]PI‐2620 PET tracer retention in patients with non‐AD, 4R tau‐related clinical syndromes, including progressive supranuclear palsy (PSP) with Richardson’s syndrome (PSP‐RS) and with predominant parkinsonism (PSP‐P), corticobasal syndrome (CBS), and nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA).Method38 participants underwent amyloid and [18F]PI‐2620 PET (Table 1). 5 mCi ± 10% of [18F]PI‐2620 was administered. [18F]PI‐2620 PET SUVR images were generated using an inferior cerebellar gray matter reference from PET data acquired 30‐60 minutes post‐injection. Mean SUVR values were extracted from each participant in neuroanatomical structures that have elevated tau burden in PSP and CBS due to corticobasal degeneration (regions of interest in Table 2). Comparison between each diagnostic group and healthy controls (HCs) was performed using a one‐tailed, independent‐samples t‐test. Spearman correlation was used to evaluate the relationship between tracer binding (SUVR) and disease severity (PSP rating scale) in patients with PSP‐RS.ResultPatients with PSP‐RS had increased tracer retention in the left globus pallidus internus and externus, left subthalamic nucleus, and left dorsolateral prefrontal cortex compared to HCs (all p < 0.05). CBS and nfvPPA patients did not have increased tracer retention at any ROIs compared to HCs, but there were low numbers of patients in these groups (Table 2, Figures 1‐3). PSP rating scale values did not correlate with tracer binding in PSP‐RS (no correlations in any regions, rs < 0.44, p > 0.05 uncorrected).Conclusion[18F]PI‐2620 PET 30‐60 minute SUVR images may have limited ability to distinguish PSP from HCs, especially on visual read, and tracer uptake did not correlate with PSP disease severity. Other post‐injection PET acquisition windows (e.g., 30‐40 minute SUVR, 0‐60 minute DVR) will be evaluated to determine if they can maximize differences between PSP and HCs. A limitation of this preliminary study is the modest number of patients and controls, with most controls provided from a different study. Additional participants are being scanned in the multicenter 4RTNI study to understand the utility of this tracer as a neuroimaging biomarker for 4R tauopathies.

AbstractBackgroundThe nucleus basalis of Meynert (nbM) is a critical hub that supplies cholinergic input throughout the cortex. Prior to even entorhinal cortex involvement, the nbM is observed to be vulnerable to tau pathology. Neuropathologic and neuroimaging studies provide strong evidence suggesting evaluation of nbM volume may be highly informative as an early biomarker of Alzheimer’s disease.MethodThe relevant AD biomarker literature with neuropathologic validation will be highlighted. Data will be provided from the FLorida Autopsied Multi‐Ethnic (FLAME) series of neuropathologically diagnosed AD cases. To enhance translational neuropathologic studies of the nbM, differences in neuronal density will be compared in the context of both typical and atypical (non‐memory) clinical presentations of AD using digital pathology to quantify nbM neurons in the postmortem tissue.ResultIn the FLAME series, we observed greater nbM neuronal loss in individuals with atypical clinical presentations (median=23/mm2) compared to typical AD dementia (median=26; p=0.002). Atypical clinical variants will be compared to provide a didactic learning experience, in addition to discussing the nbM’s influence on cortical tangle accumulation. Moreover, we will emphasize the paradoxical nature of greater nbM neuronal loss in young‐onset AD (median=21) compared to late‐onset AD (median=28; p<0.001).ConclusionEvaluation of cholinergic hub vulnerability may greatly inform our understanding of clinical heterogeneity in AD and provide key insight into early biomarker interpretation.

AbstractBackgroundOther than the typical (memory‐dominant) variant, Alzheimer’s disease (AD) can present as posterior cortical atrophy (PCA) and behavioral/dysexecutive AD. Tangle distribution differs amongst clinical variants. Neuroinflammation is important in AD pathogenesis and may contribute to Aβ and p‐tau distribution. The relationship between pathological hallmarks, neuroinflammation and, APOE genotype in (a)typical AD is still largely unknown.MethodI will discuss our most recent studies on neuroinflammation in (a)typical AD from cohorts derived from the Netherlands Brain Bank and the Mayo Clinic. Atypicality is investigated from both a neuropathological perspective(N=19) and a clinical perspective (N=30, unpublished data). Additionally, the association ofAPOE ε4 with specific Aβ deposits (i.e., the ‘coarse‐grained plaque’ and the classic cored plaque) and their underlying neuroinflammatory response is investigated (N=60, unpublished data).ResultIn neuropathologically‐defined atypical AD, microglia, and complement show an atypical distribution across regions, resembling that of p‐tau. Clinical atypical AD variants show in addition to a distinct distribution for p‐tau and Aβ, a distinct distribution for activated microglia (CD68, MHC‐II), complement (C4b), and astrocytes (GFAP) (p<.05) (Fig. 1). Furthermore, when investigating Aβ in detail, we observed an atypical plaque, defined as the ‘coarse‐grained plaque’. This APOE ε4+ plaque is associated with increased neuroinflammation and p‐tau burden (ρ(58)=0.5 and 0.6;p<.05) in contrast to the classic cored plaque.ConclusionOur data supports that not all types of Aβ deposits are associated to p‐tau damage. Neuroinflammation, a process that is differently activated within AD variants, may be the link between Aβ aggregation and subsequent neurodegeneration and contribute to clinical variability.

AbstractBackgroundBlood‐based biomarkers of amyloid and neurodegeneration are increasingly used in clinical trials and entering clinical use. Differentially mapping the plasma markers to post‐mortem neuropathology in a community‐based sample is critical for interpretation.MethodWe identified 64 Mayo Clinic Study of Aging (MCSA) participants with antemortem plasma markers (Aβ42, Aβ40, NfL, T‐tau, Aβ42/40 ratio) measured on the Quanterix Simoa HD‐1 analyzer and with postmortem neuropathologic assessments of Alzheimer’s pathology (Braak tangle stage, Thal phase, neuritic plaque burden) and cerebrovascular pathology (Strozyk scale focused on macrovascular brain changes and Kalaria scale focused on detailed micro‐ and macro‐ vascular brain changes). Weighted linear regression models with adjustment for time between plasma markers and death were conducted with exact permutation tests to evaluate the relationships between antemortem plasma and postmortem neuropathology markers.ResultHigher plasma NfL levels and Aβ42/40 ratio were associated with both cerebrovascular neuropathologic scales (p<0.05) but were not associated with Braak neurofibrillary tangle stage, neuritic plaque score, or Thal stage (p>0.5). Plasma T‐tau was not associated with any pathological assessment. Plasma Aβ42/40 and NfL explained up to 18% of the variability in cerebrovascular neuropathologic scales.ConclusionIn this community sample of participants predominantly without dementia, plasma markers for amyloid (Aβ42/40) and neurodegeneration (NfL) were associated with cerebrovascular neuropathology at autopsy. NfL is a non‐specific marker of brain injury, therefore, its association with cerebrovascular neuropathology was in the expected direction. The association between greater cerebrovascular neuropathology and elevated Aβ42/40 requires further investigation. These findings provide evidence that cerebrovascular disease may significantly influence levels of plasma biomarkers proposed for Alzheimer’s disease. This information will be important to consider for accurate clinical interpretation of the proposed biomarkers.

AbstractBackgroundDiffusion MRI (dMRI) based quantification of microstructural changes in white matter (WM) are increasingly proposed to measure cerebrovascular disease (CVD) related changes. Our objective was to compare the proposed dMRI markers using postmortem neuropathologic CVD data and then evaluate the predictors of longitudinal dMRI markers using serial scans.MethodWe identified n=51 participants (mean age: 83.8 years, 63% males) with ante‐mortem dMRI and postmortem CVD evaluation and n=718 participants (mean age: 71.1 years, 56% males) with at least two dMRI scans from the population‐based sample of Mayo Clinic Study of Aging. We computed dMRI measures proposed for measuring CVD: Free Water (FW), Fractional Anisotropy (FA) adjusted for FW (FAadj), Peak width Skeletonized Mean Diffusivity (PSMD), and FA of the genu of corpus callosum (Genu‐FA). We used the FW and PSMD (PSMD release 1.8.1) kits from the MarkVCID consortium.Using weighted linear regression models with adjustments for MRI scan time to death, we evaluated associations between the baseline dMRI and two pathology CVD scores: Strozyk (represents the presence and number of macroscopic lesions) and Kalaria (represents the summary score of vessel wall modifications) scales. We ran linear mixed effect models with all available serial dMRI measures as outcomes and vascular risk (measured by the number of cardiovascular and metabolic conditions‐CMC), baseline imaging measures (amyloid and white matter hyperintensities (WMH)) and their interaction with time as key predictors.ResultMost dMRI markers were predictors of postmortem CVD pathology (Table 1). In longitudinal dMRI models, terms associated with amyloid explained little variability in dMRI (<1%) (Table 2). WMH was a significant predictor of baseline and decline in dMRI measures with WMH explaining a considerable percentage of variability in FW (34%) and PSMD (28%). Vascular risk measures were significant predictors of three out of the four dMRI measures.ConclusionThe diffusion measures proposed as surrogate markers of CVD map reasonably well to CVD pathological scales and do not change substantially as a function of baseline amyloidosis. Our findings shed light on variability in the proposed diffusion markers using postmortem data and longitudinal imaging data. Further work is needed to evaluate their clinical utility.

AbstractBackgroundMulti‐compartment modelling of white matter (WM) microstructure using Neurite Orientation Dispersion and Density Imaging (NODDI) can provide information on WM health through the neurite (axons and dendrites) density index and free water measures. We hypothesized that cerebrovascular disease (CVD), Alzheimer’s disease (AD), and an FDG pattern suggestive of TDP‐43 proteinopathy would be associated with distinct NODDI readouts of WM damage which would be informative for identifying the substrate for cognitive impairment.MethodWe identified two independent cohorts with multi‐shell diffusion MRI, amyloid and tau PET, and cognitive assessments. One, were participants from the Mayo Clinic Study of Aging, a population‐based cohort of 347 elderly randomly sampled from the Olmsted county, Minnesota. The second were 61 amyloid positive AD participants from the Mayo AD Research Center.ResultWe observed an increase in free water and decrease in neurite density in the genu of the corpus callosum associated with vascular risk factors, which we refer to as vascular WM component (Figure 1). Tau PET signal reflective of 3R/4R tau deposition was associated with worsening neurite density index in the temporal WM where we measured parahippocampal cingulum and inferior temporal WM bundles. Worsening temporal neurite density was associated with (antemortem confirmed) FDG TDP‐43 signature. Post‐mortem neuropathologic data on a small subset (n=9) of this sample lend support to our findings. In the population‐based cohort where vascular disease was more prevalent, the vascular WM component explained variability in global cognition (partial R2 of free water and neurite density = 8.3%) and MMSE performance (8.2%) which was comparable to amyloid PET (7.4% for global cognition and 6.6% for memory) (Table 1). In the AD dementia clinic‐based cohort, tau deposition was the greatest contributor to cognitive performance (9.6%), but there was also a non‐trivial contribution of the temporal WM component (8.5%) to cognitive performance. The differences observed between the two cohorts were reflective of their distinct clinical composition.ConclusionWhite matter microstructural damage assessed using advanced diffusion models may add significant value for distinguishing the underlying substrate (whether CVD versus neurodegenerative disease caused by tau deposition or TDP‐43 pathology) for cognitive impairment in older individuals.

AbstractBackgroundTAR DNA‐binding protein 43 (TDP‐43) mislocalization is present in over 50% of patients with frontotemporal dementia and about 20% of patients with Alzheimer’s disease, but there is still an unmet need for clinical trials targeting sporadic TDP‐43 pathology in patients with dementia. The semantic variant of primary progressive aphasia (svPPA) is highly predictive of frontotemporal lobar degeneration with TDP‐43 mislocalization (FTLD‐TDP) and presents an ideal cohort in which to explore therapeutics with potential benefit across the spectrum of TDP‐43 pathology. Oxidative stress promotes mislocalization of TDP‐43 in neurons and may be a viable therapeutic target in svPPA and other FTLD‐TDP disorders. Verdiperstat is a potent, oral, CNS penetrant, myeloperoxidase inhibitor that reduces production of oxidative species from microglia. The Veri‐T trial (NCT05184569) explores the therapeutic potential of verdiperstat and is the first clinical trial to focus on patients suffering from svPPA.MethodsVeri‐T is a multisite, phase 1, randomized, double‐blind, placebo‐controlled trial. N = 64 participants with svPPA will be randomized 3:1 to oral verdiperstat (titrated to a dose of 600mg BID) or placebo for 6 months of double‐blind therapy. Neuropsychological assessments, plasma, CSF, and volumetric brain imaging are collected prior to and upon conclusion of treatment. Recruitment is ongoing at 5 ARTFL LEFFTDS Longitudinal FTLD (ALLFTD) research network clinical centers.ResultsThe primary objective is to determine the safety and tolerability of verdiperstat in svPPA. The secondary objective is to determine the pharmacokinetic profile of verdiperstat in this cohort. Exploratory endpoints are focused on identifying potential pharmacodynamic effects and identifying endpoints for future efficacy trials including plasma myeloperoxidase activity, CSF biomarkers of glial activity (chitinase‐family proteins), neurodegeneration (neurofilament light chain), and unbiased CSF proteomics (Somalogics), as well volumetric MRI changes unique to svPPA, and cognitive and language impairments measured using the ALLFTD Mobile App.ConclusionThe Veri‐T trial examines the safety, tolerability and pharmacokinetic properties of verdiperstat in svPPA, and explores novel pharmacodynamic biomarkers and outcome measures that could be employed in future efficacy studies. Veri‐T is the first multicenter clinical trial of a potentially disease modifying agent for svPPA, and the first to leverage resources of the ALLFTD network.

AbstractBackgroundThe coarse‐grained plaque (CGP) is a divergent plaque‐type recently described in Alzheimer’s disease (AD)1. In the current study, we studied the CGPs distribution over the brain, and its association with APOE, p‐tau, and neuroinflammation.MethodThe cohort (N = 60) was selected from the Mayo Clinic brain bank in Jacksonville, USA. Brain tissue from the frontal ‐, parietal ‐, temporal cortex, and the hippocampus was immunohistochemically stained for Aβ (6F/3D), p‐tau (AT8), CD68, and GFAP. The CGP and classic cored plaque (CCP) were scored as previously described1. Total plaque burden was expressed as the sum of all cortical regions.ResultThe CGP was predominantly located in the neocortex and present in ∼60% of AD cases, who were younger at onset (p<0.05) and had a lower brain weight (p<0.05) than CGP negative cases. When stratified for APOE Ɛ4+ and Ɛ4‐, CGP burden was only in Ɛ4+ positively correlated with p‐tau, Aβ, and GFAP burden in the frontal and parietal cortex (Table 1). CGP burden was not correlated with CD68. The CCP was negatively correlated with p‐tau, and not with GFAP, Aβ or CD68 (Table 1). In APOE Ɛ4+ cases, the burden of CGPs was negatively correlated with the burden of CCPs (Fig.1).ConclusionThe neocortical CGP is correlated with increased p‐tau burden and astrogliosis in APOE Ɛ4+. The CGP is inversely correlated with the common CCP, suggesting an opposite effect of Aβ‐induced tau‐toxicity for the CGP versus the CCP. 1Boon et al., Acta Neuropathologica, 2020

AbstractBackgroundTDP‐43 is a nuclear RNA‐binding protein involved in various neurodegenerative diseases, including Alzheimer’s Disease (AD), and normal aging. It strongly affects cognition and memory loss in AD. Concomitant TDP‐43 pathology increases the likelihood of being cognitively impaired at death.MethodMayo Clinic has amassed a large database with 1072 study participants with known TDP‐43 pathology status, who were prospectively recruited and followed in the Mayo Clinic Alzheimer’s Disease Research Center, Mayo Clinic Study of Aging, and Neurodegenerative Research Group. All underwent neurologic, genetic, and neuropathologic evaluations. Amygdala sections immunostained with antibodies against TDP‐43 were screened for TDP‐43‐immunoreactive inclusions and successively staged using the Josephs staging scheme. The frequency of TDP‐43 pathology by age at death was estimated using logistic regression with age modelled using a restricted cubic spline. Models were fit for all cases including the subset of 581 cases with dementia.ResultOur cohort was predominantly White (99%) with median age at death of 87 years (IQR: 80‐92) and relatively even sex distribution (52% female). About 55% had Braak stage V‐VI and 61% had Thal amyloid phase ≥3. Fifty‐two percent met criteria for intermediate‐high probability AD. TDP‐43‐immunoreactivity (TDP‐43+) was detected in 44% with median TDP‐43 stage of 3 (IQR: 1‐5), and in 54% with a median stage of 3 (IQR: 2‐5) in those with dementia. TDP‐43+ frequency increased approximately linearly with age at death. At 70 years at death, an estimated 30% (95% CI: 25–35) of the cohort was TDP‐43+ versus 33% (CI: 27–40) of those with dementia. By 90 years at death, 49% (CI: 45–52) of the overall cohort and 68% (CI:62‐73) of those with dementia were TDP‐43+.ConclusionThe results from our large cohort confirm that TDP‐43 pathology frequency increases in elderly White study participants with age of death, independent of cognitive status. Furthermore, TDP‐43 pathology frequency increases to a greater degree with age in those with dementia. Given the clear links between TDP‐43 and impaired cognition, the contribution of TDP‐43 to an individual’s cognitive impairment is likely to increase with age; a dynamic with significant public health consequences given our aging population.