Diagnostic and therapeutic agents that target alpha-synuclein in Parkinson's disease

The development of disease-modifying drugs and differential diagnostic agents is an urgent medical need in Parkinson’s disease. Despite the complex pathophysiological pathway, the misfolding of alpha-synuclein has been identified as a putative biomarker for detecting the onset and progression of the neurodegeneration associated with Parkinson’s disease. Identifying the most appropriate alpha-synuclein-based diagnostic modality with clinical translation will revolutionize the diagnosis of Parkinson’s. Likewise, molecules that target alpha-synuclein could alter the disease pathway that leads to Parkinson’s and may serve as first-in class therapeutics compared to existing treatment options such as levodopa and dopamine agonist that do not necessarily modify the disease pathway. Notwithstanding the promising benefits that alpha-synuclein presents to therapeutics and diagnostics development for Parkinson’s disease, finding ways to address potential challenges such as inadequate preclinical models, safety and efficacy will be paramount to achieving clinical translation. In this comprehensive review paper, we described the role of alpha-synuclein in the pathogenesis of Parkinson’s disease, as well as how its structure and function relationship delineate disease onset and progression. We further discussed different alpha-synuclein-based diagnostic modalities including biomolecular assays and molecular imaging. Finally, we presented current small molecules and biologics that are being developed as disease-modifying drugs or positron emission tomography imaging probes for Parkinson’s disease.

Therapy Switches in Fingolimod-Treated Patients with Multiple Sclerosis: Long-Term Experience from the German MS Registry

INTRODUCTIONS

Therapy switches in patients with multiple sclerosis (MS) receiving treatment with fingolimod occur frequently in clinical practice but are not well represented in real-world data. The aim of this study was to identify and characterize treatment switches and reveal sociodemographic/clinical changes over time in fingolimod-treated people with MS (PwMS).

METHODS

Data on 2536 fingolimod-treated PwMS extracted from the German MS Registry during different time periods were analyzed (2010-2019).

RESULTS

Overall, 28.3% of PwMS were treatment-naïve before fingolimod initiation. Interferon beta (30.7%) was the most common pre-fingolimod treatment. Ocrelizumab (19.8%) was the most frequent subsequent treatment in the 944 patients on fingolimod who switched. Between 2010 and 2019, median disease duration at fingolimod initiation decreased from 8.5 to 7.1 years (p < 0.001), and patients taking fingolimod for ≥ 1 year after treatment initiation decreased from 89.6 to 80.5% (p < 0.001). Females (p < 0.001) and young patients (p = 0.003) showed a shorter time on fingolimod. The most frequent reason for switching was disease activity (relapse/MRI) despite treatment. The annualized relapse rate increased from 0.37 in patients on fingolimod to 0.47 after treatment cessation, decreasing to 0.19 after treatment with a subsequent disease-modifying drug (DMD) was initiated.

CONCLUSION

Treatment switches from fingolimod to subsequent DMDs currently occur after shorter treatment durations than 10 years ago, possibly due to the growing treatment spectrum. Planning adequate washout periods is essential and should be done on an individualized basis.

Efficiency Model of Cladribine Tablets Versus Infusion-Based Disease-Modifying Drugs for Patients with Relapsing-Remitting Multiple Sclerosis

INTRODUCTION

To develop a simulation model assessing the efficiency of using cladribine tablets versus infusion-based disease-modifying drugs (DMDs) for the treatment of relapsing-remitting multiple sclerosis (RRMS) from a facility perspective in the UK.

METHODS

A scheduling algorithm was developed to simulate day-case admissions and calculate the mean changes to resource use and time burden for patients in a facility that transitions from infusion-based treatments to cladribine tablets over 1 year. Model inputs and assumptions were based on previous research and expert opinion. Model validation and quality checks were performed and additional scenario analyses were also conducted.

RESULTS

The model successfully scheduled all infusion treatments in the base case and no patients were left off the schedule as a result of lack of capacity. Modeled base-case outcomes increased in future scenarios owing to a 35% increase in demand. The introduction of cladribine tablets reduced these impacts. Specifically, the difference in mean daily utilization was reduced in the future scenario from 13% to 3% as 8% of patients moved to cladribine tablets; annual administration costs decreased by 96% and annual time burden decreased by 90%. Results from additional scenarios showed the largest benefits from switching current infusion patients to cladribine tablets were realized in facilities having moderate to high resource utilization.

CONCLUSIONS

This model provides facility decision-makers the ability to assess the efficiency of using cladribine tablets rather than an infusion-based DMD. The simulation quantified the benefits gained from reducing the burden on facility resources by switching some patients with RRMS from infusion-based DMDs to cladribine tablets. Overall, modeled outcomes increased in future scenarios owing to an increase in demand, although the introduction of cladribine tablets reduced this impact.

Immune Reconstitution Therapy or Continuous Immunosuppression for the Management of Active Relapsing-Remitting Multiple Sclerosis Patients? A Narrative Review

The majority of disease-modifying drugs (DMDs) available for the management of active relapsing-remitting multiple sclerosis (RMS) depend on continuous drug intake for maintained efficacy, with escalation to a more active drug when an unacceptable level of disease activity returns. Among continuously applied regimens, interferons and glatiramer acetate act as immunomodulators, while dimethyl fumarate, fingolimod, ocrelizumab, natalizumab and teriflunomide are associated with continuous immunosuppression. By contrast, immune reconstitution therapy (IRT) provides efficacy that outlasts a short course of treatment. Autologous hemopoietic stem cell transplantation is perhaps the classic example of IRT, but this invasive and intensive therapy has challenging side-effects. A short treatment course of a pharmacologic agent hypothesized to act as an IRT, such as Cladribine Tablets 3.5 mg/kg or alemtuzumab, can provide long-term suppression of MS disease activity, without need for continuous treatment (the anti-CD20 mechanism of ocrelizumab has the potential to act as an IRT, but is administered continuously, at 6-monthly intervals). Cladribine Tablets 3.5 mg/kg shows some selectivity in targeting adaptive immunity with a lesser effect on innate immunity. The introduction of IRT-like disease-modifying drugs (DMDs) challenges the traditional maintenance/escalation mode of treatment and raises new questions about how disease activity is measured. In this review, we consider a modern classification of DMDs for MS and its implications for the care of patients in the IRT era.

Observational designs in clinical multiple sclerosis research: Particulars, practices and potentialities

Observational studies investigate a wide range of topics in multiple sclerosis research. This paper presents an overview of the various observational designs and their applications in clinical studies. Observational studies are well suited for making discoveries and assessing new explanations of phenomena, but less so for establishing causal relationships, due to confounding by indication (selection bias), co-morbidity, socio-economic or other factors. Whether observational findings are demonstrative, indicative or only suggestive, depends on the research question, whether and how the design fits this question, analytical techniques, and the quality of data. Observational studies may be cross-sectional vs. longitudinal, and prospective vs. retrospective. The term 'retrograde' is proposed to explicate that cross-sectional studies may obtain data that cover (long) preceding periods. Case reports and case series are usually based on accidental observations or routinely collected data. Cross-sectional studies, by simultaneously assessing clinical phenomena and external factors, enable the discovery and quantification of associations. In ecological studies the unit of analysis is population or group, and relationships on patient level cannot be established. A cohort study is a longitudinal study that investigates patients with a defining characteristic, e.g. diagnosis or specific treatment, by analyzing data acquired at various intervals. Prospective cohort studies use (some) data that are not yet available at the time the research is conceived, whereas in retrospective studies the data already exist. In a case-control study a representative group of patients with a specific clinical feature is compared with controls, and the frequencies at which an external factor, e.g. infection, has occurred in each group is compared; in a nested case-control study controls are drawn from a fully known cohort. Randomized controlled trial (RCT)-extension studies are informative because, due to RCT randomization, they are free from confounding by indication. Patient or disease registries are organised systems for the long-term collection of uniform data on a population that is defined by a particular disease, condition or exposure, with the purpose to study changes over time. In pharmacotherapeutic research, accidental observations of unexpected beneficial effects may lead to further research into a drug's efficacy in other conditions. Uncontrolled phase 1 studies investigate safety and dosing aspects. Observational studies are alternatives to RCTs when these are not feasible for ethical or practical reasons. Phase 4 observational studies play a crucial role in the evaluation of the effectiveness of treatments in daily practice, the validation of RCT-based side effect profiles, and the discovery of late occurring or rare, potentially life-threatening side effects. Combinations of multidisciplinary longitudinal data bases into large data sets enable the development of algorithms for personalized treatments. To improve the reporting of observational findings on treatment effectiveness, it is proposed that abstracts define the research question(s) the study was meant to answer, study design and analytical methods, and identify and quantify the patient population, treatment of interest, relevant outcomes and the study's strengths and limitations. The development of guidelines for Strengthening the Reporting of Observational Studies in Effectiveness Research (STROBER), as an extension of the guidelines used in epidemiology, is wanted.

High-mobility group box 1 in multiple sclerosis

This study is one in series determining the potential of RAGE axis (receptor for advanced glycation end products, isoforms, ligands) as a biomarker in multiple sclerosis (MS). We evaluated serum levels of RAGE ligand, the high-mobility group box (HMGB)1 in MS patients, and assessed the correlation between HMGB1 serum levels and the use of disease-modifying drugs (DMDs), and between HMGB1 serum levels and indicators of MS disease severity. HMGB1 serum levels were compared between 96 (23 males) MS patients and 34 age- and gender-matched healthy controls (HCs) using enzyme-linked immunosorbent assays. DMD-naïve MS patients had significantly higher HMGB1 serum levels compared with DMD-treated (P = 0.04) and compared with HCs (P = 0.01). HMGB1 serum levels were not significantly different between total MS patients (DMD-naïve plus DMD-treated) and HCs (P = 0.09). DMD-naïve MS patients in clinical relapse tended to have lower HMGB1 serum levels than clinically stable RRMS patients (P = 0.07). HMGB1 serum levels showed 0.65 area under the curve (95 % CI 0.55-0.95) sensitivity/specificity for MS clinical relapse. The role of HMGB1 in MS disease pathology and DMD modulation of this protein warrant further investigations.

Moving toward earlier treatment of multiple sclerosis: Findings from a decade of clinical trials and implications for clinical practice

The first clinical presentation of multiple sclerosis (MS) is usually a single episode of typical symptoms and signs and is designated a "first clinical demyelinating event" (FCDE) or a "clinically isolated syndrome". Patients with an FCDE who show 'silent' magnetic resonance imaging lesions are at high risk of further clinical events and therefore of meeting the criteria for the diagnosis of clinically definite MS (CDMS). Here we review five Phase III trials, in which treatment with the following disease-modifying drugs (DMDs) was initiated at this early stage: interferon beta (ETOMS, CHAMPS, BENEFIT, and REFLEX) and glatiramer acetate (PreCISe). Differences in the design of the trials and their patient inclusion criteria limit comparisons. However, the proportion of placebo-treated patients who developed CDMS within 2 years was 38-45% across studies, and this rate was significantly reduced by DMD treatment. Conversion to McDonald MS was reported by only two of the trials: BENEFIT (2001 criteria) and REFLEX (2005 criteria). Around 85% of placebo-treated patients developed McDonald MS by 2 years in each, and again a beneficial effect of DMD treatment was seen. Overall, these studies support early use of DMDs to treat patients with an FCDE who are at high risk of conversion to CDMS.

Cladribine tablets for relapsing-remitting multiple sclerosis: Efficacy across patient subgroups from the phase III CLARITY study

BACKGROUND

In the phase III CLARITY study, treatment with cladribine tablets at cumulative doses of 3.5 or 5.25mg/kg over 96 weeks led to significant reductions in annualized relapse rates (ARR) versus placebo in patients with relapsing-remitting multiple sclerosis. Further post hoc analyses of CLARITY study data were conducted to determine the efficacy of cladribine tablets across patient subgroups stratified by baseline characteristics.

METHODS

Relapse rates over the 96-week CLARITY study were analyzed in cohorts stratified by demographics; disease duration; treatment history and disease activity at baseline.

RESULTS

In the intent-to-treat population (n=437, 433 and 456 in the placebo, cladribine 3.5 and 5.25mg/kg groups, respectively), treatment with cladribine tablets 3.5 and 5.25mg/kg led to consistent improvements in ARR versus placebo in patients stratified by gender; age (≤40/>40 years); disease duration (<3/3-10/>10 years); prior disease-modifying drug treatment (treated/naïve); relapses in the prior year (≤1/2/≥3); Expanded Disability Status Scale score (<3.5/≥3.5); T1 gadolinium-enhancing lesions (presence, absence); and T2 lesion volume (≤median/>median) at baseline (all P≤0.05 for reduction in the relative risk of relapse [cladribine tablets versus placebo]). Significant effects were also observed in patients who had only one relapse in the year prior to study entry (n=306, 303 and 323 in the placebo, cladribine 3.5 and 5.25mg/kg groups, respectively) and who were further stratified according to other measures of disease activity at baseline.

CONCLUSIONS

Treatment with cladribine tablets provides consistent reductions in ARR compared with placebo across the spectrum of baseline demographics and disease characteristics represented in the CLARITY study.