Trials Of Disease-modifying Therapies Research Articles

Risk of new disease activity in patients with multiple sclerosis who continue or discontinue disease-modifying therapies (DISCOMS): a multicentre, randomised, single-blind, phase 4, non-inferiority trial

Multiple sclerosis typically has onset in young adults and new disease activity diminishes with age. Most clinical trials of disease-modifying therapies for multiple sclerosis have not enrolled individuals older than 55 years. Observational studies suggest that risk of return of disease activity after discontinuation of a disease-modifying therapies is greatest in younger patients with recent relapses or MRI activity. We aimed to determine whether risk of disease recurrence in older patients with no recent disease activity who discontinue disease-modifying therapy is increased compared to those who remain on disease-modifying therapy. DISCOMS was a multicentre, randomised, controlled, rater-blinded, phase 4, non-inferiority trial. Individuals with multiple sclerosis of any subtype, 55 years or older, with no relapse within the past 5 years or new MRI lesion in the past 3 years while continuously taking an approved disease-modifying therapy were enrolled at 19 multiple sclerosis centres in the USA. Participants were randomly assigned (1:1 by site) with an interactive response technology system to either continue or discontinue disease-modifying therapy. Relapse assessors and MRI readers were masked to patient assignment; patients and treating investigators were not masked. The primary outcome was percentage of individuals with a new disease event, defined as a multiple sclerosis relapse or a new or expanding T2 brain MRI lesion, over 2 years. We assessed whether discontinuation of disease-modifying therapy was non-inferior to continuation using a non-inferiority, intention-to-treat analysis of all randomly assigned patients, with a predefined non-inferiority margin of 8%. This trial is registered at ClinicalTrials.gov, NCT03073603, and is completed. 259 participants were enrolled between May 22, 2017, and Feb 3, 2020; 128 (49%) were assigned to the continue group and 131 (51%) to the discontinue group. Five participants were lost to follow-up (continue n=1, discontinue n=4). Six (4·7%) of 128 participants in the continue group and 16 (12·2%) of 131 in the discontinue group had a relapse or a new or expanding brain MRI lesion within 2 years. The difference in event rates was 7·5 percentage points (95% CI 0·6-15·0). Similar numbers of participants had adverse events (109 [85%] of 128 vs 104 [79%] of 131) and serious adverse events (20 [16%] vs 18 [14%]), but more adverse events (422 vs 347) and serious adverse events (40 vs 30) occurred in the discontinue group. The most common adverse events were upper respiratory infections (20 events in 19 [15%] participants in the continue group and 37 events in 30 [23%] participants in the discontinue group). Three participants in the continue group and four in the discontinue group had treatment-related adverse events, of which one in each group was a serious adverse event (multiple sclerosis relapse requiring admission to hospital). One participant in the continue group and two in the discontinue group died; no deaths were deemed to be related to treatment. We were unable to reject the null hypothesis and could not conclude whether disease-modifying therapy discontinuation is non-inferior to continuation in patients older than 55 years with multiple sclerosis and no recent relapse or new MRI activity. Discontinuation of disease-modifying therapy might be a reasonable option in patients older than 55 years who have stable multiple sclerosis, but might be associated with a small increased risk of new MRI activity. Patient-Centered Outcomes Research Institute and the National Multiple Sclerosis Society.

β-Amyloid Load on PET Along the Continuum of Dementia With Lewy Bodies.

β-Amyloid (Aβ) plaques can co-occur with Lewy-related pathology in patients with dementia with Lewy bodies (DLB), but Aβ load at prodromal stages of DLB still needs to be elucidated. We investigated Aβ load on PET throughout the DLB continuum, from an early prodromal stage of isolated REM sleep behavior disorder (iRBD) to a stage of mild cognitive impairment with Lewy bodies (MCI-LB), and finally DLB. We performed a cross-sectional study in patients with a diagnosis of iRBD, MCI-LB, or DLB from the Mayo Clinic Alzheimer Disease Research Center. Aβ levels were measured by Pittsburgh compound B (PiB) PET, and global cortical standardized uptake value ratio (SUVR) was calculated. Global cortical PiB SUVR values from each clinical group were compared with each other and with those of cognitively unimpaired (CU) individuals (n = 100) balanced on age and sex using analysis of covariance. We used multiple linear regression testing for interaction to study the influences of sex and APOE ε4 status on PiB SUVR along the DLB continuum. Of the 162 patients, 16 had iRBD, 64 had MCI-LB, and 82 had DLB. Compared with CU individuals, global cortical PiB SUVR was higher in those with DLB (p < 0.001) and MCI-LB (p = 0.012). The DLB group included the highest proportion of Aβ-positive patients (60%), followed by MCI-LB (41%), iRBD (25%), and finally CU (19%). Global cortical PiB SUVR was higher in APOE ε4 carriers compared with that in APOE ε4 noncarriers in MCI-LB (p < 0.001) and DLB groups (p = 0.049). Women had higher PiB SUVR with older age compared with men across the DLB continuum (β estimate = 0.014, p = 0.02). In this cross-sectional study, levels of Aβ load was higher further along the DLB continuum. Whereas Aβ levels were comparable with those in CU individuals in iRBD, a significant elevation in Aβ levels was observed in the predementia stage of MCI-LB and in DLB. Specifically, APOE ε4 carriers had higher Aβ levels than APOE ε4 noncarriers, and women tended to have higher Aβ levels than men as they got older. These findings have important implications in targeting patients within the DLB continuum for clinical trials of disease-modifying therapies.

How should future clinical trials be designed in the search for disease-modifying therapies for Parkinson’s disease?

ABSTRACT Introduction Although there has been substantial progress in research and innovations in symptomatic treatments, similar success has not been achieved in disease-modifying therapy (DMT) for Parkinson’s disease (PD). Considering the enormous motor, psychosocial and financial burden associated with PD, safe and effective DMT is of paramount importance. Areas covered One of the reasons for the lack of progress in DMT for PD is poor or inappropriate design of clinical trials. In the first part of the article, the authors focus on the plausible reasons why the previous trials have failed and in the latter part, they provide their perspectives on future DMT trials. Expert opinion There are several potential reasons why previous trials have failed, including broad clinical and etiopathogenic heterogeneity of PD, poor definition and documentation of target engagement, lack of appropriate biomarkers and outcome measures, and short duration of follow-up. To address these deficiencies, future trials may consider- (i) a more customized approach to select the most suitable participants and therapeutic approaches, (ii) explore combination therapies that would target multiple pathogenetic mechanisms, and (iii) moving beyond targeting only motor symptoms to also assessing non-motor features of PD in well-designed longitudinal studies.

Disclosure of Genetic Risk Factors for Alzheimer's Disease to Cognitively Healthy Individuals-From Current Practice towards a Personalised Medicine Scenario.

Alzheimer's disease (AD) is a genetically complex disorder. In addition to the relatively small number of pathogenic variants causing autosomal dominant AD, many others have been associated with the much more common sporadic form. The E4 allele of the Apolipoprotein E (APOE) is the first discovered genetic risk factor for AD. In addition, more than 70 genetic risk loci contributing to AD have been identified. Current guidelines do not recommend AD susceptibility genetic testing in cognitively healthy adults because the implications for clinical care are limited. However, secondary prevention clinical trials of disease-modifying therapies enrol individuals based on genetic criteria, and participants are often informed of APOE testing results. Moreover, the availability of direct-to-consumer genetic testing allows individuals to learn their own AD genetic risk profile without medical supervision. A number of research protocols for AD susceptibility genetic testing have been proposed. In Italy, disclosure processes and protocols beyond those developed for inherited dementia have not been established yet. We reviewed the literature on the current practice and clinical issues related to disclosing AD genetic risk to cognitively healthy individuals and provide suggestions that may help to develop specific guidelines at the national level.

Responsiveness of UMSARS and other clinical measures in a longitudinal structured care clinic for multiple system atrophy.

As understanding of multiple system atrophy (MSA) pathophysiology improves, clinical trials of disease-modifying therapies are starting. Outcome measures responsive to disease progression will be critical, but the United MSA Rating Scale (UMSARS) has limitations. The MSA multidisciplinary clinic at the University of Texas Southwestern is a longitudinal clinic with structured assessments performed at fixed time intervals. The objective of this study was to evaluate the performance of clinical measures in assessing MSA progression over time. Data from 73 subjects with clinically diagnosed MSA were analyzed using repeated measures correlation models. Observations were made every 4months, with up to 3years of data included for each patient. UMSARS-I and UMSARS-II correlated positively with the MSA Quality of Life (QOL) scale. The rate of change was 3.12points per year (ppy) for UMSARS-I and 5.55ppy for UMSARS-II. Some individual UMSARS questions contributed more significantly than others to overall UMSARS rate of change. Based on this finding, and using repeated measures correlations between question combinations and QOL, an optimization of UMSARS parts I and II was curated. The amended UMSARS-I included 8 of the 12 subquestions, and the amended UMSARS-II included 10 of the 14 subquestions. Data from a longitudinal MSA clinic allows better characterization of the performance of UMSARS as a clinical outcome measure. A curated set of UMSARS questions appears more responsive to change and accounts for correlation with QOL, and could be the starting point for an improved MSA outcome measure.

Measures of cortical microstructure are linked to amyloid pathology in Alzheimer's disease.

Markers of downstream events are a key component of clinical trials of disease-modifying therapies for Alzheimer's disease. Morphological metrics like cortical thickness are established measures of atrophy but are not sensitive enough to detect amyloid-beta (Aβ)- related changes that occur before overt atrophy become visible. We aimed to investigate to what extent diffusion MRI can provide sensitive markers of cortical microstructural changes and to test their associations with multiple aspects of the Alzheimer's disease pathological cascade, including both Aβ and tau accumulation, astrocytic activation and cognitive deficits. We applied the mean apparent diffusion propagator model to diffusion MRI data from 492 cognitively unimpaired elderly and patients with mild cognitive impairment from the Swedish BioFINDER-2 cohort. Participants were stratified in Aβ-negative/tau-negative, Aβ-positive/tau-negative and Aβ-positive/tau-positive based on Aβ- and tau-PET uptake. Cortical regional values of diffusion MRI metrics and cortical thickness were compared across groups. Associations between regional values of diffusion MRI metrics and both Aβ- and tau-PET uptake were also investigated along with the association with plasma level of glial fibrillary acidic protein (GFAP), a marker of astrocyte activation (available in 292 participants). Mean squared displacement revealed widespread microstructural differences already between Aβ-negative/tau-negative and Aβ-positive/tau-negative participants with a spatial distribution that closely resembled the pattern of Aβ accumulation. In contrast, differences in cortical thickness were clearly more limited. Mean squared displacement was also correlated with both Aβ- and tau-PET uptake even independently from one another and from cortical thickness. Further, the same metric exhibited significantly stronger correlations with PET uptake than cortical thickness (P < 0.05). Mean squared displacement was also positively correlated with GFAP with a pattern that resembles Aβ accumulation, and GFAP partially mediated the association between Aβ accumulation and mean squared displacement. Further, impairments in executive functions were significantly more associated with mean squared displacement values extracted from a meta-region of interest encompassing regions accumulating Aβ early in the disease process, than with cortical thickness (P < 0.05). Similarly, impairments in memory functions were significantly more associated with mean squared displacement values extracted from a temporal meta-region of interest than with cortical thickness (P < 0.05). Metrics of cortical microstructural alteration derived from diffusion MRI are highly sensitive to multiple aspects of the Alzheimer's disease pathological cascade. Of particular interest is the link with both Aβ-PET and GFAP, suggesting diffusion MRI might reflects microstructural changes related to the astrocytic response to Aβ aggregation. Therefore, metrics of cortical diffusion might be important outcome measures in anti-Aβ treatments clinical trials for detecting drug-induced changes in cortical microstructure.

Epidemiology of Progressive Supranuclear Palsy: Real World Data from the Second Largest Health Plan in Israel.

Progressive supranuclear palsy (PSP) is a rare and fatal neurodegenerative movement disorder and no disease modifying therapy (DMT) is currently available. This study aims to assess the epidemiology of PSP in Israel and to describe its clinical features. This retrospective analysis identified patients with PSP between 2000 and 2018 over the age of 40 years at first diagnosis (index date). We identified 209 patients with ≥1 diagnosis of PSP. Of those, 88 patients satisfied the inclusion criteria with a mean age at diagnosis of 72 years (SD = 8) and 53% were female. The 2018 prevalence and incidence rates were 5.3 and 1 per 100,000 persons, respectively. Median survival time was 4.9 years (95% CI 3.6–6.1) and median time from initial symptom to diagnosis was 4.2 years. The most common misdiagnoses were Parkinson’s disease, cognitive disorder and depression. The present study demonstrates that the clinic-epidemiological features of PSP in Israel are similar to PSP worldwide. In light of PSP’s rarity, investigation of PSP cohorts in different countries may create a proper platform for upcoming DMT trials.

Combining biomarkers for prognostic modelling of Parkinson’s disease

BackgroundPatients with Parkinson’s disease (PD) have variable rates of progression. More accurate prediction of progression could improve selection for clinical trials. Although some variance in clinical progression can be predicted...

Brain Perfusion Single-Photon Emission Computed Tomography Using an Easy Z-Score Imaging System Predicts Progression to Neurodegenerative Dementia in Rapid Eye Movement Sleep Behavior Disorder

Introduction: Longitudinal studies have reported that patients with idiopathic rapid eye movement sleep behavior disorder (IRBD) have an increased risk of developing synucleinopathies, such as Parkinson’s disease and dementia with Lewy bodies (DLB). Clinical trials of disease-modifying therapies for IRBD patients require suitable biomarkers that can predict the short-term onset of neurodegenerative dementia. Methods: We retrospectively examined if easy Z-score imaging system-specific volume-of-interest analysis (SVA) using brain perfusion single-photon emission computed tomography (SPECT) imaging or the cingulate island sign score can predict the short-term development of neurodegenerative dementia in 30 patients with IRBD. Results: Ten patients (33.3%) who exceeded the thresholds for three indicators (severity, extent, and ratio) were included in an SVA-positive group, while 20 (66.7%) were included in an SVA-negative group. Nine (30.0%) IRBD patients had phenoconversion, of which eight had DLB and one had Parkinson’s disease with dementia. In Kaplan-Meier analysis, patients in the SVA-positive group converted to neurodegenerative dementia in a significantly shorter period of time compared to patients in the SVA-negative group. Conclusions: These data suggest that SVA-positive IRBD patients have an increased short-term risk of developing neurodegenerative dementia.

Prediagnostic Progressive Supranuclear Palsy – Insights from the UK Biobank

IntroductionPrediagnostic features of Parkinson's Disease are well described but prediagnostic Progressive Supranuclear Palsy (PSP) is less understood. The diagnosis of PSP is delayed by an average of three years after symptom onset. Understanding the changes that occur in the prediagnostic period will aid earlier diagnosis, clarify the natural history, and may aid the design of early disease-modifying therapy trials. We set out to identify motor and cognitive markers of prediagnostic PSP, with Parkinson's disease as a comparator condition, in a large prospective cohort. MethodsBaseline UK Biobank data from 502,504 individuals were collected between 2006 and 2010. Subsequent PSP and Parkinson's disease cases were identified from primary and secondary care electronic health records' diagnostic coding data and death registry, with 5404 matched controls. Results176 PSP cases (time to diagnosis 7.8 ± 2.8 years) and 2526 Parkinson's disease cases (time to diagnosis 7.8 ± 2.9 years) were identified. At baseline, those later diagnosed with PSP had slower reaction times, weaker hand grip, lower fluid intelligence, prospective memory, self-rated health scores and digit recall than controls. Reaction times were correlated with time to diagnosis. The PSP group had higher mortality than both Parkinson's disease and control groups. ConclusionsMotor slowing, cognitive dysfunction, and postural instability are clinical diagnostic features of PSP that are typically symptomatic three years before diagnosis. Objective markers of these features were evident on average 7.8 years before diagnosis. Our findings suggest the existence of a long prediagnostic phase in PSP, with subtle changes in motor and cognitive function.

Impact of non-binding FDA guidances on primary endpoint selection in Alzheimer's disease trials.

IntroductionThe U.S. Food and Drug Administration (FDA)'s guidances help describe the agency's current thinking on regulatory issues and serve as a means of informal policymaking that is non‐binding. This study examines the impact of two guidance documents for Alzheimer's disease (AD) trials. The first guidance in 2013 encouraged the use of cognitive/functional endpoints, while the second in 2018 modified such recommendation.MethodsUsing pivotal trial data, we applied a regression discontinuity in time (RDiT) framework to examine trialist response to these guidance documents. Results were stratified by disease‐modifying therapy (DMT) status, and controlled for disease staging, FDA registration status, and trial phase.ResultsAmong AD DMT trials, annual use of cognitive/functional composite endpoints significantly increased after the 2013 guidance (+12.9%, P < .001), and significantly decreased after the 2018 guidance (–19.9%, P = .022).DiscussionAlthough guidance documents do not set new legal standards or impose binding requirements, our findings indicate they are broadly followed by AD trialists.

CoreSCD: multi-stakeholder consensus on core outcomes for sickle cell disease clinical trials

BackgroundWith the dramatic increase in the pipeline for new sickle cell disease (SCD) therapies in recent years, the time is ripe to ensure a robust body of evidence is available for decision making by regulators, payers, clinicians, and patients. Harmonization of the outcomes selected across interventional trials enables optimal post-trial appraisal and decision making through valid pooled analyses and indirect comparisons. We employed a structured, multi-stakeholder consensus process to develop core outcome sets (COS) for use in clinical trials of SCD interventions.MethodsCoreSCD utilized a modified Delphi method adapted from the standards recommended by the Core Outcome Measures in Effectiveness Trials (COMET) Initiative. An initial list of candidate outcomes was developed through a targeted literature review and input from an 11-member advisory committee. A 44-member multi-stakeholder Delphi Panel was established and included patients and family members, advocates, clinicians, researchers, payers, health technology assessors, representatives from government agencies, and industry representatives. Patients/advocates comprised 25% of the Delphi Panel and orientation and training was provided prior to the consensus process to ensure all were prepared to participate meaningfully. Panelists completed three rounds of an online survey to rate the importance of candidate outcomes for inclusion in the COS. Summary data was provided between each voting round and an in-person consensus meeting was held between the second and third round of voting. Consensus rules were applied following each round of voting to eliminate outcomes that did not meet predetermined criteria for retention.ResultsConsensus was reached for two core outcome sets. The final COS for trials of disease-modifying therapies includes ten outcomes and the COS for trials of acute interventions includes six outcomes. Both core sets include clinical outcomes as well as outcomes related to functioning/quality of life, resource utilization, and survival/mortality.ConclusionsUse of the COS in clinical development programs for SCD will help to ensure that relevant, consistent outcomes are available for decision making across the product lifecycle.

Genetic Stratification of Age-Dependent Parkinson's Disease Risk by Polygenic Hazard Score.

Parkinson's disease (PD) is a highly age-related disorder, where common genetic risk variants affect both disease risk and age at onset. A statistical approach that integrates these effects across all common variants may be clinically useful for individual risk stratification. A polygenic hazard score methodology, leveraging a time-to-event framework, has recently been successfully applied in other age-related disorders. We aimed to develop and validate a polygenic hazard score model in sporadic PD. Using a Cox regression framework, we modeled the polygenic hazard score in a training data set of 11,693 PD patients and 9841 controls. The score was then validated in an independent test data set of 5112 PD patients and 5372 controls and a small single-study sample of 360 patients and 160 controls. A polygenic hazard score predicts the onset of PD with a hazard ratio of 3.78 (95% confidence interval 3.49-4.10) when comparing the highest to the lowest risk decile. Combined with epidemiological data on incidence rate, we apply the score to estimate genetically stratified instantaneous PD risk across age groups. We demonstrate the feasibility of a polygenic hazard approach in PD, integrating the genetic effects on disease risk and age at onset in a single model. In combination with other predictive biomarkers, the approach may hold promise for risk stratification in future clinical trials of disease-modifying therapies, which aim at postponing the onset of PD. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The Discovery of α-Synuclein in Lewy Pathology of Parkinson's Disease: The Inspiration of a Revolution.

The Discovery of α-Synuclein in Lewy Pathology of Parkinson's Disease: The Inspiration of a Revolution.

Clinical progression of progressive supranuclear palsy: impact of trials bias and phenotype variants.

Progressive supranuclear palsy causes diverse clinical presentations, including classical Richardson’s syndrome and several variant phenotypes. Clinical trials of disease-modifying therapies have recently been completed, with more planned for the next 2 years. However, many people with progressive supranuclear palsy do not meet eligibility criteria for these clinical trials. Understanding clinical progression with different phenotypes would improve trial design and enhance the accuracy of risk–benefit and cost–benefit assessments of new treatments for progressive supranuclear palsy. We set out to determine rates of motor and cognitive progression of possible, probable and definite progressive supranuclear palsy, with different phenotypes, from a representative cohort in a regional UK healthcare service. Longitudinal clinical data from people with Richardson’s syndrome and variant phenotypes were analysed using linear mixed-modelling, using both the full and modified versions of the Progressive Supranuclear Palsy Rating Scale, Mini-Mental State Examination and the revised Addenbrooke’s Cognitive Examination. Subgroup analyses considered patients meeting recent Phase II trial entry criteria and patients with neuropathological confirmation. Two hundred and twenty-seven patients [male = 59%, mean age (±standard deviation), 71.8 (±7.0) years] were followed for a mean 21.6 (±15.6) months. One hundred and seventy-four (77%) had Richardson’s syndrome at the outset, 25 had cortical variant presentations (13%, frontal, corticobasal, speech and language variants) and 28 had subcortical variant presentations (14%, parkinsonism, postural instability and gait freezing variants). Across all participants, annual progression in Richardson’s syndrome was faster than variant phenotypes on the Mini-Mental State Examination (−1.8 versus −0.9/year, P = 0.005) and revised Addenbrooke’s Cognitive Examination (−5.3 versus −3.0/year, P = 0.01) but not the Progressive Supranuclear Palsy Rating Scale (9.0 versus 7.1/year, P = 0.2) nor the modified Progressive Supranuclear Palsy Rating Scale (2.7 versus 2.3/year, P = 0.4). However, for those with more than 1 years’ follow-up, a significant difference was observed between Richardson’s syndrome and variant phenotypes in Progressive Supranuclear Palsy Rating Scale (8.7 versus 6.3/year, P = 0.04). Survival was longer in variant phenotypes than Richardson’s syndrome [7.3 (±3.9) versus 5.6 (±2.0) years, P = 0.02]. Pathologically confirmed cases (n = 49) supported these findings. Patients meeting basic trial-eligibility criteria (n = 129) progressed faster on the Progressive Supranuclear Palsy Rating Scale than trial-not-eligible patients (10.1 versus 6.1/year, P = 0.001). In conclusion, phenotypes other than Richardson’s syndrome show slower progression and longer survival. Trial criteria do not select representative progressive supranuclear palsy cases. This has implications for trial design, and application of trial results to clinically more diverse patient populations.

Alpha-Synuclein Oligomers and Neurofilament Light Chain Predict Phenoconversion of Pure Autonomic Failure.

To explore the role of alpha-synuclein (αSyn) oligomers and neurofilament light chain (NfL) in cerebrospinal fluid (CSF) of patients with pure autonomic failure (PAF) as markers of future phenoconversion to multiple system atrophy (MSA). Well-characterized patients with PAF (n=32) were enrolled between June 2016 and February 2019 at Mayo Clinic Rochester and followed prospectively with annual visits to determine future phenoconversion to MSA, Parkinson's disease (PD), or dementia with Lewy bodies (DLB). ELISA was utilized to measure NfL and protein misfolding cyclic amplification (PMCA) to detect αSyn oligomers in CSF collected at baseline. Patients were followed for a median of 3.9 years. Five patients converted to MSA, 2 to PD, and 2 to DLB. NfL at baseline was elevated only in patients who later developed MSA, perfectly separating those from future PD and DLB converters as well as non-converters. ASyn-PMCA was positive in all but two cases (94%). The PMCA reaction was markedly different in five samples with maximum fluorescence and reaction kinetics previously described in MSA patients; all of these patients later developed MSA. αSyn-PMCA is almost invariably positive in the CSF of patients with PAF establishing this condition as α-synucleinopathy. Both NfL and the magnitude and reaction kinetics of αSyn PMCA faithfully predict which PAF patients will eventually phenoconvert to MSA. This finding has important implications not only for prognostication, but also for future trials of disease modifying therapies, allowing for differentiation of MSA from Lewy body synucleinopathies before motor symptoms develop. ANN NEUROL 2021;89:1212-1220.

Uncovering Pathways to Personalized Therapies in Type 1 Diabetes.

The goal of personalized medicine is to match the right drugs to the right patients at the right time. Personalized medicine has been most successful in cases where there is a clear genetic linkage between a disease and a therapy. This is not the case with type 1 diabetes (T1D), a genetically complex immune-mediated disease of β-cell destruction. Researchers over decades have traced the natural history of disease sufficiently to use autoantibodies as predictive biomarkers for disease risk and to conduct successful clinical trials of disease-modifying therapy. Recent studies, however, have highlighted heterogeneity associated with progression, with nonuniform rate of insulin loss and distinct features of the peri-diagnostic period. Likewise, there is heterogeneity in immune profiles and outcomes in response to therapy. Unexpectedly, from these studies demonstrating perplexing complexity in progression and response to therapy, new biomarker-based principles are emerging for how to achieve personalized therapies for T1D. These include therapy timed to periods of disease activity, use of patient stratification biomarkers to align therapeutic target with disease endotype, pharmacodynamic biomarkers to achieve personalized dosing and appropriate combination therapies, and efficacy biomarkers for “treat-to-target” strategies. These principles provide a template for application of personalized medicine to complex diseases.

A Modified Progressive Supranuclear Palsy Rating Scale.

The Progressive Supranuclear Palsy Rating Scale is a prospectively validated physician-rated measure of disease severity for progressive supranuclear palsy. We hypothesized that, according to experts' opinion, individual scores of items would differ in relevance for patients' quality of life, functionality in daily living, and mortality. Thus, changes in the score may not equate to clinically meaningful changes in the patient's status. The aim of this work was to establish a condensed modified version of the scale focusing on meaningful disease milestones. Sixteen movement disorders experts evaluated each scale item for its capacity to capture disease milestones (0=no, 1=moderate, 2=severe milestone). Items not capturing severe milestones were eliminated. Remaining items were recalibrated in proportion to milestone severity by collapsing across response categories that yielded identical milestone severity grades. Items with low sensitivity to change were eliminated, based on power calculations using longitudinal 12-month follow-up data from 86 patients with possible or probable progressive supranuclear palsy. The modified scale retained 14 items (yielding 0-2 points each). The items were rated as functionally relevant to disease milestones with comparable severity. The modified scale was sensitive to change over 6 and 12 months and of similar power for clinical trials of disease-modifying therapy as the original scale (achieving 80% power for two-sample t test to detect a 50% slowing with n=41 and 25% slowing with n=159 at 12 months). The modified Progressive Supranuclear Palsy Rating Scale may serve as a clinimetrically sound scale to monitor disease progression in clinical trials and routine. © 2021 International Parkinson and Movement Disorder Society.

Modeling the Progression of Speech Deficits in Cerebellar Ataxia Using a Mixture Mixed-Effect Machine Learning Framework

Background: Accurate and reliable prediction of changes in the severity of Cerebellar Ataxia (CA) will be helpful in trials of disease-modifying therapies. This study demonstrated that objective acoustic measures were more sensitive than perceptive analysis through the Scale for the Assessment and Rating of Ataxia (SARA) in assessing CA progression, within a time window of two years (mean). Method: Thirtyseven people with CA were tested at baseline (time point 1, TP1) and two years later (time point 2, TP2). A machine-learning framework with a robust three-step feature selection criterion and a Bayesian data-driven clustering technique based on the multivariate mixture extension of the generalized linear mixed model (GLMM) was used. The outcomes included two (time and cepstral-based) objective speech parameters recorded at TP1 and TP2. For testing subjects, the dynamic prediction was conducted using samples from the posterior distributions of parameter estimates and random effects. This study further employed the penalized expected deviance (PED) criterion for model comparison and the selection of the number of groups in the clustering procedure. Results: First, the selected objective speech metrics in the individual patients showed a significant worsening of the speech impairment (p<0.001, Kolmogorov–Smirnov test) from TP1 through TP2. Second, the cluster analysis divided the CA patients into two distinct subgroups showing a strong association between objective speech measures and disease duration, with ~96% of observed values falling within the 95% credible intervals. Third, for the training data, our multivariate model (PEDFea1+Fea2=5175; number of groups=2) performed more reliably than the univariate models (PEDFea1=4225, PEDFea2=3850; number of groups=2) in discriminating the CA patients. Fourth, the individual-level predictions of the change in profiles of the objective measures over time were performed for the testing data. Conclusion: Such a framework using objective speech metrics indeed holds promise to predict the rate of clinical progression of Ataxic Speech in individuals with CA.

Disease duration in autosomal dominant familial Alzheimer disease: A survival analysis.

ObjectiveTo use survival modeling to estimate disease duration in autosomal dominant familial Alzheimer disease (ADAD) and ascertain whether factors influencing age at onset also affect survival.MethodsSymptomatic mutation carriers (201 presenilin 1 [PSEN1] and 55 amyloid precursor protein [APP]) from ADAD families referred to the Dementia Research Centre, between 1987 and 2019, were included. Survival was assessed with respect to age at onset, year of birth, APOE ε4 status, cognitive presentation, and sex using multilevel mixed-effects Weibull survival models. The contribution of mutation and family to variance in age at onset and duration was also assessed.ResultsEstimated mean survival was 11.6 (10.4–12.9) years and was similar for APP and PSEN1 mutations. Sixty-seven percent of the variance in age at onset was explained by mutation and 72% by mutation and family together. In contrast, only 6% of the variance in disease duration was explained by mutation specificity and 18% by family membership. Irrespective of gene, survival appeared longer for successive generations and in individuals with atypical presentations. Older age at onset was associated with longer duration within PSEN1 and shorter duration within APP mutation carriers. No differences in survival time were found between sexes or between mutations located before or beyond codon 200 within PSEN1.ConclusionsSurvival is influenced by mutation to a much lesser extent than age at onset. Survival time has increased over time and is longer in atypical presentations. These insights may inform the interpretation of disease-modifying therapy trials in ADAD.