Predicting Cerebrospinal Fluid Alpha-Synuclein Seed Amplification Assay Status from Demographics and Clinical Data.

Objective: To develop and externally validate models to predict probabilities of alpha-synuclein (a-syn) positive or negative status in vivo in a mixture of people with and without Parkinson's disease (PD) using easily accessible clinical predictors. Methods: Uni- and multi-variable logistic regression models were developed in a cohort of participants from the Parkinson Progression Marker Initiative (PPMI) study to predict cerebrospinal fluid (CSF) a-syn status as measured by seeding amplification assay (SAA). Models were externally validated in a cohort of participants from the Systemic Synuclein Sampling Study (S4) that had also measured CSF a-syn status using SAA. Results: The PPMI model training/testing cohort consisted of 1260 participants, of which 76% had manifest PD with a mean (± standard deviation) disease duration of 1.2 (±1.6) years. Overall, 68.7% of the overall PPMI cohort (and 88.0% with PD of those with manifest PD) had positive CSF a-syn SAA status results. Variables from the full multivariable model to predict CSF a-syn SAA status included age- and sex-specific University of Pennsylvania Smell Identification Test (UPSIT) percentile values, sex, self-reported presence of constipation problems, leucine-rich repeat kinase 2 (LRRK2) genetic status and pathogenic variant, and GBA status. Internal performance of the model on PPMI data to predict CSF a-syn SAA status had an area under the receiver operating characteristic curve (AUROC) of 0.920, and sensitivity/specificity of 0.881/0.845. When this model was applied to the external S4 cohort, which included 71 participants (70.4% with manifest PD for a mean 5.1 (±4.8) years), it performed well, achieving an AUROC of 0.976, and sensitivity/specificity of 0.958/0.870. Models using only UPSIT percentile performed similarly well upon internal and external testing. Conclusion: Data-driven models using non-invasive clinical features can accurately predict CSF a-syn SAA positive and negative status in cohorts enriched for people living with PD. Scores from the UPSIT were highly significant in predicting a-syn SAA status.

LRRK2-Associated Parkinsonism With and Without In Vivo Evidence of Alpha-Synuclein Aggregates.

Background: Among LRRK2-associated parkinsonism cases with nigral degeneration, over two-thirds demonstrate evidence of pathologic alpha-synuclein, but many do not. Understanding the clinical phenotype and underlying biology in such individuals is critical for therapeutic development. Our objective was to compare clinical and biomarker features, and rate of progression over 4 years follow-up, among LRRK2-associated parkinsonism cases with and without in vivo evidence of alpha-synuclein aggregates. Methods: Data were from the Parkinson's Progression Markers Initiative, a multicenter prospective cohort study. The sample included individuals diagnosed with Parkinson disease with pathogenic variants in LRRK2. Presence of CSF alpha-synuclein aggregation was assessed with seed amplification assay. A range of clinician- and patient- reported outcome assessments were administered. Biomarkers included dopamine transporter SPECT scan, CSF amyloid-beta1-42, total tau, phospho-tau181, urine bis(monoacylglycerol)phosphate levels, and serum neurofilament light chain. Linear mixed effects models examined differences in trajectory in CSF negative and positive groups. Results: 148 LRRK2-parkinsonism cases (86% with G2019S variant), 46 negative and 102 positive for CSF alpha-synuclein seed amplification assay were included. At baseline, the negative group were older than the positive group (median [interquartile range] 69.1 [65.2-72.3] vs 61.5 [55.6-66.9] years, p<0.001) and a greater proportion were female (28 (61%) vs 43 (42%), p=0.035). Despite being older, the negative group had similar duration since diagnosis, and similar motor rating scale (16 [11-23] vs 16 [10-22], p=0.480) though lower levodopa equivalents. Only 13 (29%) of the negative group were hyposmic, compared to 75 (77%) of the positive group. Lowest putamen dopamine transporter binding expected for age and sex was greater in the negative vs positive groups (0.36 [0.29-0.45] vs 0.26 [0.22-0.37], p<0.001). Serum neurofilament light chain was higher in the negative group compared to the positive group (17.10 [13.60-22.10] vs 10.50 [8.43-14.70]; age-adjusted p-value=0.013). In terms of longitudinal change, the negative group remained stable in functional rating scale score in contrast to the positive group who had a significant increase (worsening) of 0.729 per year (p=0.037), but no other differences in trajectory were found. Conclusion: Among individuals diagnosed with Parkinson disease with pathogenic variants in the LRRK2 gene, we found clinical and biomarker differences in cases without versus with in vivo evidence of CSF alpha-synuclein aggregates. LRRK2 parkinsonism cases without evidence of alpha-synuclein aggregates as a group exhibit less severe motor manifestations and decline may have more significant cognitive dysfunction. The underlying biology in LRRK2-parkinsonism cases without evidence of alpha-synuclein aggregates requires further investigation.

Continuous Levodopa Delivery with an Intraoral Micropump System: An Open-Label Pharmacokinetics and Clinical Study.

BACKGROUND: Double-blind studies have demonstrated that motor complications in Parkinson's disease (PD) can be reduced with continuous delivery of levodopa. The DopaFuse system is a novel, intraoral micropump that attaches to a retainer and uses a propellant to deliver levodopa/carbidopa (LD/CD) continuously into the mouth. OBJECTIVES: Evaluate the safety, pharmacokinetics, and efficacy of LD/CD delivered via the DopaFuse system compared to treatment with intermittent doses of standard oral LD/CD in PD patients with motor fluctuations. METHODS: This was a 2-week, open-label study (NCT04778176) in 16 PD patients treated with ≥4 levodopa doses/day and experiencing motor fluctuations. On Day 1 (clinic setting) patients received their usual dose of standard LD/CD; DopaFuse therapy was initiated on Day 2, and on Day 3 patients received DopaFuse plus a morning oral LD/CD dose. Patients returned home on Days 4-14 and returned for in-clinic assessment on Day 15. RESULTS: Continuous DopaFuse delivery of LD/CD was associated with reduced variability in plasma levodopa levels compared to oral LD/CD (mean ± SD levodopa Fluctuation Index reduced from 2.15 ± 0.59 on Day1 to 1.50 ± 0.55 on Day 2 (P = 0.0129) and to 1.03 ± 0.53 on Day 3 (P < 0.0001)). This pharmacokinetic improvement translated into significantly reduced OFF time with DopaFuse therapy (reduction of -1.72 ± 0.37 h at Day 15; P = 0.0004) and increased ON time without severe dyskinesias (increase of 1.72 ± 0.37 h at Day 15; P = 0.0004) versus oral LD/CD administration. DopaFuse therapy was not associated with any clinically significant adverse events. CONCLUSIONS: Continuous delivery of LD/CD using the DopaFuse system was associated with significantly less variability in plasma levodopa concentrations and reductions in OFF time compared to treatment with standard oral LD/CD therapy and was well tolerated. © 2024 International Parkinson and Movement Disorder Society.

Twelve Years of Drug Prioritization to Help Accelerate Disease Modification Trials in Parkinson's Disease: The International Linked Clinical Trials Initiative.

In 2011, the UK medical research charity Cure Parkinson's set up the international Linked Clinical Trials (iLCT) committee to help expedite the clinical testing of potentially disease modifying therapies for Parkinson's disease (PD). The first committee meeting was held at the Van Andel Institute in Grand Rapids, Michigan in 2012. This group of PD experts has subsequently met annually to assess and prioritize agents that may slow the progression of this neurodegenerative condition, using a systematic approach based on preclinical, epidemiological and, where possible, clinical data. Over the last 12 years, 171 unique agents have been evaluated by the iLCT committee, and there have been 21 completed clinical studies and 20 ongoing trials associated with the initiative. In this review, we briefly outline the iLCT process as well as the clinical development and outcomes of some of the top prioritized agents. We also discuss a few of the lessons that have been learnt, and we conclude with a perspective on what the next decade may bring, including the introduction of multi-arm, multi-stage clinical trial platforms and the possibility of combination therapies for PD.

Safety and efficacy of continuous subcutaneous levodopa-carbidopa infusion (ND0612) for Parkinson's disease with motor fluctuations (BouNDless): a phase 3, randomised, double-blind, double-dummy, multicentre trial.

BACKGROUND: Conventional oral levodopa therapy for the treatment of Parkinson's disease can be associated with variations in plasma concentrations. Levodopa infusion strategies might provide more consistent drug delivery and fewer motor fluctuations. We aimed to assess the safety and efficacy of a continuous 24 h/day subcutaneous infusion of ND0612 (a levodopa-carbidopa solution) compared with oral immediate-release levodopa-carbidopa for the treatment of motor fluctuations in people with Parkinson's disease. METHODS: We conducted a phase 3, randomised, double-blind, double-dummy, active-controlled, multicentre trial at 117 academic and community neurology sites in 16 countries, including in Europe, Israel, and the USA. Eligible participants were men and women aged 30 years or older with a diagnosis of Parkinson's disease (Hoehn and Yahr stage ≤3 in the on state) who experienced at least 2·5 h/day of off time. Participants underwent an open-label run-in phase (<12 weeks), during which time optimal regimens were established for both oral immediate-release levodopa-carbidopa and for 24 h/day subcutaneous ND0612 infusion (levodopa-carbidopa 60·0/7·5 mg/mL), with supplemental oral levodopa-carbidopa if needed. Participants were then randomly assigned (1:1) to 12 weeks of double-blind treatment with their optimised regimen of either subcutaneous ND0612 or oral levodopa-carbidopa, with matching oral or subcutaneous placebo given as required to maintain blinding. Randomisation was done via an interactive web response system, stratified by region, using a permuted block schedule. Participants, study partners, treating investigators, study site personnel, and the sponsor were masked to treatment group allocation. The primary efficacy endpoint was the change from baseline (ie, time of randomisation, when all patients were receiving an optimised open-label ND0612 regimen) to end of the double-blind phase in total daily on time without troublesome dyskinesia, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, NCT04006210, and is complete. FINDINGS: Between Sept 30, 2019, and April 8, 2022, 381 participants were enrolled, of whom 259 (68%) were randomly assigned, 128 (49%) to subcutaneous ND0612 and 131 (51%) to oral levodopa-carbidopa. 243 (94%) participants completed the study. Treatment with subcutaneous ND0612 provided an additional 1·72 h (95% CI 1·08 to 2·36) of on time without troublesome dyskinesia compared with oral levodopa-carbidopa (change from baseline of -0·48 h [-0·94 to -0·02] with subcutaneous ND0612 vs -2·20 h [-2·65 to -1·74] with oral levodopa-carbidopa; p<0·0001). Significant treatment differences favouring subcutaneous ND0612 were also found in the first four of nine prespecified hierarchical outcomes of daily off time (-1·40 h [95% CI -1·99 to -0·80]), Movement Disorders Society-Unified Parkinson's Disease Rating Scale part II scores (-3·05 [-4·28 to -1·81]), Patients Global Impression of Change (odds ratio [OR] 5·31 [2·67 to 10·58]), and Clinical Global Impression of Improvement (OR 7·23 [3·57 to 14·64]). Hierarchical testing ended after the fourth secondary endpoint. Adverse events were reported by 287 (89%) of 322 participants during open-label ND0612 optimisation, and by 103 (80%) of 128 in the ND0612 group and 97 (74%) of 131 in the oral levodopa-carbidopa group during the double-blind phase. The most common adverse events were infusion-site reactions (266 [83%] participants during open-label ND0612, and 73 [57%] in the ND0612 group vs 56 [43%] in the oral levodopa-carbidopa group during the double-blind phase), most of which were mild. Serious adverse events in four participants in the ND0612 group were related to study treatment (infusion-site cellulitis [n=2], infusion-site abscess and infusion-site ulcer [n=1]; and paraesthesia and peripheral sensorimotor neuropathy [n=1]). One participant in the ND0612 group died during the double-blind phase, but the death was not related to study treatment (fall leading to traumatic brain injury). INTERPRETATION: Results of this phase 3 study showed that subcutaneous ND0612 used in combination with oral immediate-release levodopa-carbidopa increased on time without troublesome dyskinesia and reduced off time, with a favourable benefit-risk profile. ND0612 might offer a safe and efficacious subcutaneous levodopa infusion approach to managing motor fluctuations in people with Parkinson's disease. The ongoing open-label extension phase will provide further information on the long-term efficacy and safety of treatment. FUNDING: NeuroDerm.

Dry-Cleaning Chemicals and a Cluster of Parkinson's Disease and Cancer: A Retrospective Investigation.

BACKGROUND: Environmental exposure to trichloroethylene (TCE), a carcinogenic dry-cleaning chemical, may be linked to Parkinson's disease (PD). OBJECTIVE: The objective of this study was to determine whether PD and cancer were elevated among attorneys who worked near a contaminated site. METHODS: We surveyed and evaluated attorneys with possible exposure and assessed a comparison group. RESULTS: Seventy-nine of 82 attorneys (96.3%; mean [SD] age: 69.5 [11.4] years; 89.9% men) completed at least one phase of the study. For comparison, 75 lawyers (64.9 [10.2] years; 65.3% men) underwent clinical evaluations. Four (5.1%) of them who worked near the polluted site reported PD, more than expected based on age and sex (1.7%; P = 0.01) but not significantly higher than the comparison group (n = 1 [1.3%]; P = 0.37). Fifteen (19.0%), compared to four in the comparison group (5.3%; P = 0.049), had a TCE-related cancer. CONCLUSIONS: In a retrospective study, diagnoses of PD and TCE-related cancers appeared to be elevated among attorneys who worked next to a contaminated dry-cleaning site. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Evaluation of ATNPD Framework and Biofluid Markers to Predict Cognitive Decline in Early Parkinson Disease.

BACKGROUND AND OBJECTIVES: In Parkinson disease (PD), Alzheimer disease (AD) copathology is common and clinically relevant. However, the longitudinal progression of AD CSF biomarkers-ß-amyloid 1-42 (Aß42), phosphorylated tau 181 (p-tau181), and total tau (t-tau)-in PD is poorly understood and may be distinct from clinical AD. Moreover, it is unclear whether CSF p-tau181 and serum neurofilament light (NfL) have added prognostic utility in PD, when combined with CSF Aß42. First, we describe longitudinal trajectories of biofluid markers in PD. Second, we modified the AD ß-amyloid/tau/neurodegeneration (ATN) framework for application in PD (ATNPD) using CSF Aß42 (A), p-tau181 (T), and serum NfL (N) and tested ATNPD prediction of longitudinal cognitive decline in PD. METHODS: Participants were selected from the Parkinson's Progression Markers Initiative cohort, clinically diagnosed with sporadic PD or as controls, and followed up annually for 5 years. Linear mixed-effects models (LMEMs) tested the interaction of diagnosis with longitudinal trajectories of analytes (log transformed, false discovery rate [FDR] corrected). In patients with PD, LMEMs tested how baseline ATNPD status (AD [A+T+N±] vs not) predicted clinical outcomes, including Montreal Cognitive Assessment (MoCA; rank transformed, FDR corrected). RESULTS: Participants were 364 patients with PD and 168 controls, with comparable baseline mean (±SD) age (patients with PD = 62 ± 10 years; controls = 61 ± 11 years]; Mann-Whitney Wilcoxon: p = 0.4) and sex distribution (patients with PD = 231 male individuals [63%]; controls = 107 male individuals [64%]; χ2: p = 1). Patients with PD had overall lower CSF p-tau181 (ß = -0.16, 95% CI -0.23 to -0.092, p = 2.2e-05) and t-tau than controls (ß = -0.13, 95% CI -0.19 to -0.065, p = 4e-04), but not Aß42 (p = 0.061) or NfL (p = 0.32). Over time, patients with PD had greater increases in serum NfL than controls (ß = 0.035, 95% CI 0.022 to 0.048, p = 9.8e-07); slopes of patients with PD did not differ from those of controls for CSF Aß42 (p = 0.18), p-tau181 (p = 1), or t-tau (p = 0.96). Using ATNPD, PD classified as A+T+N± (n = 32; 9%) had worse cognitive decline on global MoCA (ß = -73, 95% CI -110 to -37, p = 0.00077) than all other ATNPD statuses including A+ alone (A+T-N-; n = 75; 21%). DISCUSSION: In patients with early PD, CSF p-tau181 and t-tau were low compared with those in controls and did not increase over 5 years of follow-up. Our study shows that classification using modified ATNPD (incorporating CSF Aß42, CSF p-tau181, and serum NfL) can identify biologically relevant subgroups of PD to improve prediction of cognitive decline in early PD.

A biological definition of neuronal α-synuclein disease: towards an integrated staging system for research.

Parkinson's disease and dementia with Lewy bodies are currently defined by their clinical features, with α-synuclein pathology as the gold standard to establish the definitive diagnosis. We propose that, given biomarker advances enabling accurate detection of pathological α-synuclein (ie, misfolded and aggregated) in CSF using the seed amplification assay, it is time to redefine Parkinson's disease and dementia with Lewy bodies as neuronal α-synuclein disease rather than as clinical syndromes. This major shift from a clinical to a biological definition of Parkinson's disease and dementia with Lewy bodies takes advantage of the availability of tools to assess the gold standard for diagnosis of neuronal α-synuclein (n-αsyn) in human beings during life. Neuronal α-synuclein disease is defined by the presence of pathological n-αsyn species detected in vivo (S; the first biological anchor) regardless of the presence of any specific clinical syndrome. On the basis of this definition, we propose that individuals with pathological n-αsyn aggregates are at risk for dopaminergic neuronal dysfunction (D; the second biological anchor). Our biological definition establishes a staging system, the neuronal α-synuclein disease integrated staging system (NSD-ISS), rooted in the biological anchors (S and D) and the degree of functional impairment caused by clinical signs or symptoms. Stages 0-1 occur without signs or symptoms and are defined by the presence of pathogenic variants in the SNCA gene (stage 0), S alone (stage 1A), or S and D (stage 1B). The presence of clinical manifestations marks the transition to stage 2 and beyond. Stage 2 is characterised by subtle signs or symptoms but without functional impairment. Stages 2B-6 require both S and D and stage-specific increases in functional impairment. A biological definition of neuronal α-synuclein disease and an NSD-ISS research framework are essential to enable interventional trials at early disease stages. The NSD-ISS will evolve to include the incorporation of data-driven definitions of stage-specific functional anchors and additional biomarkers as they emerge and are validated. Presently, the NSD-ISS is intended for research use only; its application in the clinical setting is premature and inappropriate.

Safety, tolerability, and efficacy of NLY01 in early untreated Parkinson's disease: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Converging lines of evidence suggest that microglia are relevant to Parkinson's disease pathogenesis, justifying exploration of therapeutic agents thought to attenuate pathogenic microglial function. We sought to test the safety and efficacy of NLY01-a brain-penetrant, pegylated, longer-lasting version of exenatide (a glucagon-like peptide-1 receptor agonist) that is believed to be anti-inflammatory via reduction of microglia activation-in Parkinson's disease. METHODS: We report a 36-week, randomised, double-blind, placebo-controlled study of NLY01 in participants with early untreated Parkinson's disease conducted at 58 movement disorder clinics in the USA. Participants meeting UK Brain Bank or Movement Disorder Society research criteria for Parkinson's disease were randomly allocated (1:1:1) to one of two active treatment groups (2·5 mg or 5·0 mg NLY01) or matching placebo, based on a central computer-generated randomisation scheme using permuted block randomisation with varying block sizes. All participants, investigators, coordinators, study staff, and sponsor personnel were masked to treatment assignments throughout the study. The primary efficacy endpoint for the primary analysis population (defined as all randomly assigned participants who received at least one dose of study drug) was change from baseline to week 36 in the sum of Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) parts II and III. Safety was assessed in the safety population (all randomly allocated participants who received at least one dose of the study drug) with documentation of adverse events, vital signs, electrocardiograms, clinical laboratory assessments, physical examination, and scales for suicidality, sleepiness, impulsivity, and depression. This trial is complete and registered at ClinicalTrials.gov, NCT04154072. FINDINGS: The study took place between Jan 28, 2020, and Feb 16, 2023. 447 individuals were screened, of whom 255 eligible participants were randomly assigned (85 to each study group). One patient assigned to placebo did not receive study treatment and was not included in the primary analysis. At 36 weeks, 2·5 mg and 5·0 mg NLY01 did not differ from placebo with respect to change in sum scores on MDS-UPDRS parts II and III: difference versus placebo -0·39 (95% CI -2·96 to 2·18; p=0·77) for 2·5 mg and 0·36 (-2·28 to 3·00; p=0·79) for 5·0 mg. Treatment-emergent adverse events were similar across groups (reported in 71 [84%] of 85 patients on 2·5 mg NLY01, 79 [93%] of 85 on 5·0 mg, and 73 [87%] of 84 on placebo), with gastrointestinal disorders the most commonly observed class in active groups (52 [61%] for 2·5 mg, 64 [75%] for 5·0 mg, and 30 [36%] for placebo) and nausea the most common event overall (33 [39%] for 2·5 mg, 49 [58%] for 5·0 mg, and 16 [19%] for placebo). No deaths occurred during the study. INTERPRETATION: NLY01 at 2·5 and 5·0 mg was not associated with any improvement in Parkinson's disease motor or non-motor features compared with placebo. A subgroup analysis raised the possibility of motor benefit in younger participants. Further study is needed to determine whether these exploratory observations are replicable. FUNDING: D&D Pharmatech-Neuraly.

Transdermal Nicotine Treatment and Progression of Early Parkinson's Disease.

BACKGROUND: Epidemiologic studies show that smokers have a lower incidence of Parkinson's disease. Nicotine has been hypothesized to slow progression in early Parkinson's disease. METHODS: In a double-blind, placebo-controlled multicenter trial, we randomly assigned patients with Parkinson's disease, diagnosed within 18 months, who were in Hoehn and Yahr disease stage less than or equal to 2 (range from 0 to 5; higher scores indicate greater impairment), who were therapy naïve (except for stable monoamine-oxidase-B inhibition), and not requiring dopaminergic therapy, to transdermal nicotine or placebo. The primary end point was change in Unified Parkinson's Disease Rating Scale parts I­III (Total UPDRS) score (range from 0 to 172; higher scores indicate greater impairment) between baseline and 60 weeks (52 weeks of trial therapy, 8 weeks of washout). The first secondary end point was change in Total UPDRS from baseline to 52 weeks. Differences between groups were estimated using the Hodges­Lehmann (HL) method and tested with the exact two-sided stratified Mann­Whitney­Wilcoxon test according to the intention-to-treat principle. RESULTS: Among 163 participants, 101 were assessed for the primary end point. Mean worsening of Total UPDRS was 3.5 in the placebo versus 6.0 in the nicotine group (HL-difference with 95% CI: ­3 [­6 to 0], P=0.06). For the first secondary end point, analysis of 138 participants showed a mean worsening of 5.4 in the placebo versus 9.1 in the nicotine group (HL-difference with 95% CI: ­4 [­7 to ­1]). Dropout was mainly because of early treatment discontinuation or adverse events. Cutaneous adverse effects at the patch application site were common. In all, 34.6% of participants initiated dopaminergic therapy during participation. CONCLUSIONS: One-year transdermal nicotine treatment did not slow progression in early Parkinson's disease. (Funded by the Michael J. Fox Foundation for Parkinson's Research and others; ClinicalTrials.gov number, NCT01560754; EudraCT number, 2010-020299-42.)