Cladribine: mode of action and implications for treatment of multiple sclerosis

Therapeutic choices and disease activity after 2 years of treatment with cladribine: An Italian multicenter study (CladStop)

BACKGROUND AND PURPOSE

Cladribine tablets, a purine analogue antimetabolite, offer a unique treatment regimen, involving short courses at the start of the first and second year, with no further treatment needed in years 3 and 4. However, comprehensive evidence regarding patient outcomes beyond the initial 24 months of cladribine treatment is limited.

METHODS

This retrospective, multicenter study enrolled 204 patients with multiple sclerosis who had completed the 2-year course of cladribine treatment. The primary outcomes were therapeutic choices and clinical disease activity assessed by annualized relapse rate after the 2-year treatment course.

RESULTS

A total of 204 patients were enrolled; most patients (75.4%) did not initiate new treatments in the 12 months postcladribine. The study found a significant reduction in annualized relapse rate at the 12-month follow-up after cladribine completion compared to the year prior to starting therapy (0.07 ± 0.25 vs. 0.82 ± 0.80, p < 0.001). Furthermore, patients with relapses during cladribine treatment were more likely to start new therapies, whereas older patients were less likely. The safety profile of cladribine was favorable, with lymphopenia being the primary registered adverse event.

CONCLUSIONS

This study provides insights into therapeutic choices and disease activity following cladribine treatment. It highlights cladribine's effectiveness in reducing relapse rates and disability progression, reaffirming its favorable safety profile. Real-world data, aligned with previous reports, draw attention to ocrelizumab and natalizumab as common choices after cladribine. However, larger, prospective studies for validation and a more comprehensive understanding of cladribine's long-term impact are necessary.

Prospective observational study to evaluate treatment satisfaction and effectiveness in patients with relapsing multiple sclerosis starting cladribine tablets (CLADREAL) in Italy

Disease-modifying therapies (DMTs) for multiple sclerosis (MS) reduce relapse frequency, magnetic resonance imaging (MRI) activity, and slow disability progression. Numerous DMTs are approved for relapsing forms of MS although real-world data on patient-reported outcomes (PROs) and quality of life (QoL) are needed to inform treatment choice. Immune reconstitution therapy with cladribine tablets is a highly effective treatment for relapsing MS (RMS). We present the protocol for an observational study to prospectively assess the effectiveness of cladribine tablets on clinical and MRI parameters as well as on PROs, including treatment satisfaction, QoL, sleep quality, self-perceived health, fatigue, and physical function. Enrolled patients at study sites in Italy will be adults with RMS (including relapsing-remitting and active secondary progressive MS) who are either treatment naïve or have received at least one first-line disease modifying DMT or no more than one second-line DMT. The primary objective will be change in global treatment satisfaction measured with the Treatment Satisfaction Questionnaire for Medication Version 1.4 approximately 24 months after initiating cladribine tablets in patients switching from previous DMTs. Secondary objectives will include global treatment satisfaction at earlier timepoints, will comprise treatment naïve patients, and will quantify treatment effectiveness and tolerability. We will also assess relapses, disability progression, MRI activity, and other PROs at approximately 12 and 24 months. The findings will provide insight from daily clinical practice into the patient's experience to complement data from controlled trials and inform treatment choice. EU PAS Registration Number EUPAS49334 filed 17/10/2022.

Magnetic Resonance Imaging Evidence Supporting the Efficacy of Cladribine Tablets in the Treatment of Relapsing-Remitting Multiple Sclerosis

Numerous therapies are currently available to modify the disease course of multiple sclerosis (MS). Magnetic resonance imaging (MRI) plays a pivotal role in assessing treatment response by providing insights into disease activity and clinical progression. Integrating MRI findings with clinical and laboratory data enables a comprehensive assessment of the disease course. Among available MS treatments, cladribine is emerging as a promising option due to its role as a selective immune reconstitution therapy, with a notable impact on B cells and a lesser effect on T cells. This work emphasizes the assessment of MRI's contribution to MS treatment, particularly focusing on the influence of cladribine tablets on imaging outcomes, encompassing data from pivotal and real-world studies. The evidence highlights that cladribine, compared with placebo, not only exhibits a reduction in inflammatory imaging markers, such as T1-Gd+, T2 and combined unique active (CUA) lesions, but also mitigates the effect on brain volume loss, particularly within grey matter. Importantly, cladribine reveals early action by reducing CUA lesions within the first months of treatment, regardless of a patient's initial conditions. The selective mechanism of action, and sustained efficacy beyond year 2, combined with its early onset of action, collectively position cladribine tablets as a pivotal component in the therapeutic paradigm for MS. Overall, MRI, along with clinical measures, has played a substantial role in showcasing the effectiveness of cladribine in addressing both the inflammatory and neurodegenerative aspects of MS.

Consensus recommendations for diagnosis and treatment of Multiple Sclerosis: 2023 revision of the MENACTRIMS guidelines

With evolving diagnostic criteria and the advent of new oral and parenteral therapies for Multiple Sclerosis (MS), most current diagnostic and treatment algorithms need revision and updating. The diagnosis of MS relies on incorporating clinical and paraclinical findings to prove dissemination in space and time and exclude alternative diseases that can explain the findings at hand. The differential diagnostic workup should be guided by clinical and laboratory red flags to avoid unnecessary tests. Appropriate selection of MS therapies is critical to maximize patient benefit. The current guidelines review the current diagnostic criteria for MS and the scientific evidence supporting treatment of acute relapses, radiologically isolated syndrome, clinically isolated syndrome, relapsing remitting MS, progressive MS, pediatric cases and pregnant women. The purpose of these guidelines is to provide practical recommendations and algorithms for the diagnosis and treatment of MS based on current scientific evidence and clinical experience.

The role of CD56bright NK cells in neurodegenerative disorders

Emerging evidence suggests a potential role for natural killer (NK) cells in neurodegenerative diseases, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. However, the precise function of NK cells in these diseases remains ambiguous. The existence of two NK cell subsets, CD56bright and CD56dim NK cells, complicates the understanding of the contribution of NK cells in neurodegeneration as their functions within the context of neurodegenerative diseases may differ significantly. CD56bright NK cells are potent cytokine secretors and are considered more immunoregulatory and less terminally differentiated than their mostly cytotoxic CD56dim counterparts. Hence, this review focusses on NK cells, specifically on CD56bright NK cells, and their role in neurodegenerative diseases. Moreover, it explores the mechanisms underlying their ability to enter the central nervous system. By consolidating current knowledge, we aim to provide a comprehensive overview on the role of CD56bright NK cells in neurodegenerative diseases. Elucidating their impact on neurodegeneration may have implications for future therapeutic interventions, potentially ameliorating disease pathogenesis.

5-methylcytosine RNA modification regulators-based patterns and features of immune microenvironment in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous malignant disease of the blood cell. The current therapies for AML are unsatisfactory and the molecular mechanisms underlying AML are unclear. 5-methylcytosine (m5C) is an important posttranscriptional modification of mRNA, and is involved in the regulation of mRNA stability, translation, and other aspects of RNA metabolism. However, based on our knowledge of published literature, the role of the m5C regulators has not been explored in AML till date. In this study, we clarified the expression and gene variants of m5C regulators in AML and found that most m5C regulators were differentially expressed and correlated with disease prognosis. We also found that the methylation status of certain m5C regulators (e.g., DNMT3A, DNMT3B) affects the survival of AML patients. Two m5C modification subtypes, and high- and low-risk subgroups identified based on the expression of m5C regulators showed significant differences in the prognosis as well as immune cell infiltration. In addition, most of the m5C regulators were found to be correlated with miRNA expression in AML, as well as IC50 values of many drugs. The miRNA and GSVA analysis were used to identify the different miRNAs and KEGG or hallmark pathways between high- and low-risk subgroups. We also built a prognostic model based on m5C regulators, which was validated by two GSE databases. To verify the reliability of our analysis and conclusions, qPCR was used to identify the expressions of m5C regulators between normal and AML. In summary, we comprehensively explored the molecular characteristics of m5C regulators and built a prognostic model in AML. We proposed new mechanistic insights into the role of m5C in multiple databases and clinical data, which may pave novel ways for the development of therapeutic strategies.

The evolution of multiple sclerosis disease-modifying therapies: An update for pharmacists

PURPOSE

Multiple sclerosis (MS) and the evolution of disease-modifying therapies (DMTs) and their indications, mechanisms of action, efficacy, pregnancy class, and cost are discussed.

SUMMARY

MS is an immune-mediated, demyelinating, and progressive neurological disorder that can cause both motor and cognitive deficits. Onset of MS typically occurs between the ages of 20 and 40 years, and the disease can result in significant disability over time. Since the introduction of the first DMT for the treatment of MS in 1993, significant progress has been made in the development of new classes of DMTs with different mechanisms of action, higher efficacy, and simpler administration schedules, offering patients better alternatives. However, drawbacks with the use of DMTs include their increasing cost and formulary restrictions.

CONCLUSION

The treatment landscape of MS has significantly changed over the past 2 decades, and the introduction of newer classes of DMTs provides an opportunity for pharmacists to play an important role in the management of this patient population.

Immunomodulators and immunosuppressants for relapsing-remitting multiple sclerosis: a network meta-analysis

BACKGROUND

Different therapeutic strategies are available for the treatment of people with relapsing-remitting multiple sclerosis (RRMS), including immunomodulators, immunosuppressants and biological agents. Although each one of these therapies reduces relapse frequency and slows disability accumulation compared to no treatment, their relative benefit remains unclear. This is an update of a Cochrane review published in 2015.

OBJECTIVES

To compare the efficacy and safety, through network meta-analysis, of interferon beta-1b, interferon beta-1a, glatiramer acetate, natalizumab, mitoxantrone, fingolimod, teriflunomide, dimethyl fumarate, alemtuzumab, pegylated interferon beta-1a, daclizumab, laquinimod, azathioprine, immunoglobulins, cladribine, cyclophosphamide, diroximel fumarate, fludarabine, interferon beta 1-a and beta 1-b, leflunomide, methotrexate, minocycline, mycophenolate mofetil, ofatumumab, ozanimod, ponesimod, rituximab, siponimod and steroids for the treatment of people with RRMS.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, and two trials registers were searched on 21 September 2021 together with reference checking, citation searching and contact with study authors to identify additional studies. A top-up search was conducted on 8 August 2022.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that studied one or more of the available immunomodulators and immunosuppressants as monotherapy in comparison to placebo or to another active agent, in adults with RRMS.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies and extracted data. We considered both direct and indirect evidence and performed data synthesis by pairwise and network meta-analysis. Certainty of the evidence was assessed by the GRADE approach.

MAIN RESULTS

We included 50 studies involving 36,541 participants (68.6% female and 31.4% male). Median treatment duration was 24 months, and 25 (50%) studies were placebo-controlled. Considering the risk of bias, the most frequent concern was related to the role of the sponsor in the authorship of the study report or in data management and analysis, for which we judged 68% of the studies were at high risk of other bias. The other frequent concerns were performance bias (34% judged as having high risk) and attrition bias (32% judged as having high risk). Placebo was used as the common comparator for network analysis. Relapses over 12 months: data were provided in 18 studies (9310 participants). Natalizumab results in a large reduction of people with relapses at 12 months (RR 0.52, 95% CI 0.43 to 0.63; high-certainty evidence). Fingolimod (RR 0.48, 95% CI 0.39 to 0.57; moderate-certainty evidence), daclizumab (RR 0.55, 95% CI 0.42 to 0.73; moderate-certainty evidence), and immunoglobulins (RR 0.60, 95% CI 0.47 to 0.79; moderate-certainty evidence) probably result in a large reduction of people with relapses at 12 months. Relapses over 24 months: data were reported in 28 studies (19,869 participants). Cladribine (RR 0.53, 95% CI 0.44 to 0.64; high-certainty evidence), alemtuzumab (RR 0.57, 95% CI 0.47 to 0.68; high-certainty evidence) and natalizumab (RR 0.56, 95% CI 0.48 to 0.65; high-certainty evidence) result in a large decrease of people with relapses at 24 months. Fingolimod (RR 0.54, 95% CI 0.48 to 0.60; moderate-certainty evidence), dimethyl fumarate (RR 0.62, 95% CI 0.55 to 0.70; moderate-certainty evidence), and ponesimod (RR 0.58, 95% CI 0.48 to 0.70; moderate-certainty evidence) probably result in a large decrease of people with relapses at 24 months. Glatiramer acetate (RR 0.84, 95%, CI 0.76 to 0.93; moderate-certainty evidence) and interferon beta-1a (Avonex, Rebif) (RR 0.84, 95% CI 0.78 to 0.91; moderate-certainty evidence) probably moderately decrease people with relapses at 24 months. Relapses over 36 months findings were available from five studies (3087 participants). None of the treatments assessed showed moderate- or high-certainty evidence compared to placebo. Disability worsening over 24 months was assessed in 31 studies (24,303 participants). Natalizumab probably results in a large reduction of disability worsening (RR 0.59, 95% CI 0.46 to 0.75; moderate-certainty evidence) at 24 months. Disability worsening over 36 months was assessed in three studies (2684 participants) but none of the studies used placebo as the comparator. Treatment discontinuation due to adverse events data were available from 43 studies (35,410 participants). Alemtuzumab probably results in a slight reduction of treatment discontinuation due to adverse events (OR 0.39, 95% CI 0.19 to 0.79; moderate-certainty evidence). Daclizumab (OR 2.55, 95% CI 1.40 to 4.63; moderate-certainty evidence), fingolimod (OR 1.84, 95% CI 1.31 to 2.57; moderate-certainty evidence), teriflunomide (OR 1.82, 95% CI 1.19 to 2.79; moderate-certainty evidence), interferon beta-1a (OR 1.48, 95% CI 0.99 to 2.20; moderate-certainty evidence), laquinimod (OR 1.49, 95 % CI 1.00 to 2.15; moderate-certainty evidence), natalizumab (OR 1.57, 95% CI 0.81 to 3.05), and glatiramer acetate (OR 1.48, 95% CI 1.01 to 2.14; moderate-certainty evidence) probably result in a slight increase in the number of people who discontinue treatment due to adverse events. Serious adverse events (SAEs) were reported in 35 studies (33,998 participants). There was probably a trivial reduction in SAEs amongst people with RRMS treated with interferon beta-1b as compared to placebo (OR 0.92, 95% CI 0.55 to 1.54; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

We are highly confident that, compared to placebo, two-year treatment with natalizumab, cladribine, or alemtuzumab decreases relapses more than with other DMTs. We are moderately confident that a two-year treatment with natalizumab may slow disability progression. Compared to those on placebo, people with RRMS treated with most of the assessed DMTs showed a higher frequency of treatment discontinuation due to AEs: we are moderately confident that this could happen with fingolimod, teriflunomide, interferon beta-1a, laquinimod, natalizumab and daclizumab, while our certainty with other DMTs is lower. We are also moderately certain that treatment with alemtuzumab is associated with fewer discontinuations due to adverse events than placebo, and moderately certain that interferon beta-1b probably results in a slight reduction in people who experience serious adverse events, but our certainty with regard to other DMTs is lower. Insufficient evidence is available to evaluate the efficacy and safety of DMTs in a longer term than two years, and this is a relevant issue for a chronic condition like MS that develops over decades. More than half of the included studies were sponsored by pharmaceutical companies and this may have influenced their results. Further studies should focus on direct comparison between active agents, with follow-up of at least three years, and assess other patient-relevant outcomes, such as quality of life and cognitive status, with particular focus on the impact of sex/gender on treatment effects.

Impact of Disease-Modifying Therapies on Gut-Brain Axis in Multiple Sclerosis

Multiple sclerosis is a chronic, autoimmune-mediated, demyelinating disease whose pathogenesis remains to be defined. In past years, in consideration of a constantly growing number of patients diagnosed with multiple sclerosis, the impacts of different environmental factors in the pathogenesis of the disease have been largely studied. Alterations in gut microbiome composition and intestinal barrier permeability have been suggested to play an essential role in the regulation of autoimmunity. Thus, increased efforts are being conducted to demonstrate the complex interplay between gut homeostasis and disease pathogenesis. Numerous results confirm that disease-modifying therapies (DMTs) used for the treatment of MS, in addition to their immunomodulatory effect, could exert an impact on the intestinal microbiota, contributing to the modulation of the immune response itself. However, to date, the direct influence of these treatments on the microbiota is still unclear. This review intends to underline the impact of DMTs on the complex system of the microbiota-gut-brain axis in patients with multiple sclerosis.

Phenolic compounds as potential adenosine deaminase inhibitors: molecular docking and dynamics simulation coupled with MM-GBSA calculations

Adenosine deaminase (ADA) is a Zn2+-containing enzyme that catalyzes the irreversible deamination of adenosine to inosine or deoxyadenosine to deoxyinosine. In addition to this enzymatic function, ADA mediates cell-to-cell interactions involved in lymphocyte co-stimulation or endothelial activation. ADA is implicated in cardiovascular pathologies such as atherosclerosis and certain types of cancers, including lymphoma and leukemia. To date, only two drugs (pentostatin and cladribine) have been approved for the treatment of hairy cell leukemia. In search of natural ADA inhibitors, we demonstrated the binding of selected phenolic compounds to the active site of ADA using molecular docking and molecular dynamics simulation. Our results show that phenolic compounds (chlorogenic acid, quercetin, and hyperoside) stabilized the ADA complex by forming persistent interactions with the catalytically essential Zn2+ ion. Furthermore, MM-GBSA ligand binding affinity calculations revealed that hyperoside had a comparable binding energy score (ΔG = - 46.56 ± 8.26 kcal/mol) to that of the cocrystal ligand in the ADA crystal structure (PDB ID: 1O5R) (ΔG = - 51.97 ± 4.70 kcal/mol). Similarly, chlorogenic acid exhibited a binding energy score (ΔG = - 18.76 ± 4.60 kcal/mol) comparable to those of the two approved ADA inhibitor drugs pentostatin (ΔG = - 14.54 ± 2.25 kcal/mol) and cladribine (ΔG = - 25.52 ± 4.10 kcal/mol) while quercetin was found to have modest binding affinity (ΔG = - 8.85 ± 7.32 kcal/mol). This study provides insights into the possible inhibitory potential of these phenolic compounds against ADA.

Elucidating Compound Mechanism of Action and Polypharmacology with a Large-scale Perturbational Profile Compendium

The Mechanism of Action (MoA) of a drug is generally represented as a small, non-tissue-specific repertoire of high-affinity binding targets. Yet, drug activity and polypharmacology are increasingly associated with a broad range of off-target and tissue-specific effector proteins. To address this challenge, we have implemented an efficient integrative experimental and computational framework leveraging the systematic generation and analysis of drug perturbational profiles representing >700 FDA-approved and experimental oncology drugs, in cell lines selected as high-fidelity models of 23 aggressive tumor subtypes. Protein activity-based analyses revealed highly reproducible, drug-mediated modulation of tissue-specific targets, leading to generation of a proteome-wide polypharmacology map, characterization of MoA-related drug clusters and off-target effects, and identification and experimental validation of novel, tissue-specific inhibitors of undruggable oncoproteins. The proposed framework, which is easily extended to elucidating the MoA of novel small-molecule libraries, could help support more systematic and quantitative approaches to precision oncology.

Cladribine Tablets Mode of Action, Learning from the Pandemic: A Narrative Review

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system, characterized by chronic, inflammatory, demyelinating, and neurodegenerative processes. MS management relies on disease-modifying drugs that suppress/modulate the immune system. Cladribine tablets (CladT) have been approved by different health authorities for patients with various forms of relapsing MS. The drug has been demonstrated to deplete CD4+ and CD8+ T-cells, with a higher effect described in the former, and to decrease total CD19+, CD20+, and naive B-cell counts. COVID-19 is expected to become endemic, suggesting its potential infection risk for immuno-compromised patients, including MS patients treated with disease-modifying drugs. We report here the available data on disease-modifying drug-treated-MS patients and COVID-19 infection and vaccination, with a focus on CladT. MS patients treated with CladT are not at higher risk of developing severe COVID-19. While anti-SARS-CoV-2 vaccination is recommended in all MS patients with guidelines addressing vaccination timing according to the different disease-modifying drugs, no vaccination timing restrictions seem to be necessary for cladribine, based on its mechanism of action and available evidence. Published data suggest that CladT treatment does not impact the production of anti-SARS-CoV-2 antibodies after COVID-19 vaccination, possibly due to its relative sparing effect on naïve B-cells and the rapid B-cell reconstitution following treatment. Slightly lower specific T-cell responses are likely not impacting the risk of breakthrough COVID-19. It could be stated that cladribine's transient effect on innate immune cells likely contributes to maintaining an adequate first line of defense against the SARS-CoV-2 virus.

Disease-modifying therapies do not affect sleep quality or daytime sleepiness in a large Australian MS cohort

BACKGROUND

Poor sleep is common in multiple sclerosis (MS) and may impact daily functioning. The extent to which disease-modifying therapies (DMTs) contribute to sleep outcomes is under-examined.

OBJECTIVE

To compare the effects of DMTs on sleep outcomes in an Australian cohort of people with MS and investigate associations between DMT use and beliefs about sleep problems and daily functioning (social functioning and activity engagement).

METHODS

Sleep outcomes were assessed using the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale. DMT use and functioning were self-reported.

RESULTS

Of 1,715 participants, 64% used a DMT. No differences in sleep outcomes were detected between participants who did and did not use DMTs, the type of DMT used (lower vs higher efficacy, interferon-β vs other DMTs), the timing of administration, or adherence to standard administration recommendations. Beliefs that DMT use worsened sleep were associated with poorer sleep quality and perceptions that sleep problems interfered with daily functioning.

CONCLUSION

The use of a DMT does not appear to affect self-reported sleep outcomes in people with MS. However, beliefs that DMT use makes sleep worse were associated with poorer sleep quality and increased interference in daily functioning, suggesting a need for education to diminish negative perceptions of DMT use.

Safety and efficacy of cladribine in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Previously, several studies investigated the effect of cladribine among patients with multiple sclerosis (MS) as a treatment option. Due to the contradictory results of previous studies regarding the efficacy and safety of cladribine in the MS population, we aimed to conduct a systematic review and meta-analysis by including clinical trials and observational studies in terms of having more confirmative results to make a general decision.

METHODS

The three databases including PubMed, Scopus, and Web of Science were comprehensively searched in May 2022. We included the studies that investigated the efficacy and safety of cladribine in patients with MS. Eligible studies have to provide sufficient details on MS diagnosis and appropriate follow-up duration. We investigated the efficacy of cladribine with several outcomes including Expanded Disability Status Scale (EDSS) change, progression-free survival (PFS), relapse-free survival (RFS), and MRI-free activity survival (MFAS).

RESULTS

After two-step reviewing, 23 studies were included in our qualitative and quantitative synthesis. The pooled SMD for EDSS before and after treatment was - 0.54 (95%CI: - 1.46, 0.39). Our analysis showed that the PFS after cladribine use is 79% (95%CI 71%, 86%). Also, 58% of patients with MS who received cladribine remained relapse-free (95%CI 31%, 83%). Furthermore, the MFAS after treatment was 60% (95%CI 36%, 81%). Our analysis showed that infection is the most common adverse event after cladribine treatment with a pooled prevalence of 10% (95%CI 4%, 18%). Moreover, the pooled prevalence of infusion-related adverse events was 9% (95%CI 4%, 15%). Also, the malignancies after cladribine were present in 0.4% of patients (95%CI 0.25%, 0.75%).

CONCLUSION

Our results showed acceptable safety and efficacy for cladribine for the treatment of MS except in terms of reducing EDSS. Combination of our findings with the results of previous studies which compared cladribine to other disease-modifying therapies (DMTs), cladribine seems to be a safe and effective drug in achieving better treatment for relapsing-remitting MS (RRMS) patients.

Multiple sclerosis patients treated with cladribine tablets: expert opinion on practical management after year 4

Multiple sclerosis (MS) is a chronic, progressive neurological disease involving neuroinflammation, neurodegeneration, and demyelination. Cladribine tablets are approved for immune reconstitution therapy in patients with highly active relapsing-remitting MS based on favorable efficacy and tolerability results from the CLARITY study that have been confirmed in long-term extension studies. The approved 4-year dosing regimen foresees a cumulative dose of 3.5 mg/kg administered in two cycles administered 1 year apart, followed by 2 years of observation. Evidence on managing patients beyond year 4 is scarce; therefore, a group of 10 neurologists has assessed the available evidence and formulated an expert opinion on management of the growing population of patients now completing the approved 4-year regimen. We propose five patient categories based on response to treatment during the first 4-year regimen, and corresponding management pathways that envision close monitoring with clinical visits, magnetic resonance imaging (MRI) and/or biomarkers. At the first sign of clinical or radiological disease activity, patients should receive a highly effective disease-modifying therapy, comprising either a full cladribine regimen as described in regulatory documents (cumulative dose 7.0 mg/kg) or a comparably effective treatment. Re-treatment decisions should be based on the intensity and timing of onset of disease activity, clinical and radiological assessments, as well as patient eligibility for treatment and treatment preference.

An update on combination therapies for multiple sclerosis: where are we now?

INTRODUCTION

In theory, combination of two agents, which are suboptimal when given individually, may result in a significant increase in therapeutic effect. Combination therapies have proven particularly effective against infections such as HIV, cancer, and also chronic autoimmune diseases such as rheumatoid arthritis.

AREAS COVERED

The authors review the literature, searching for randomized placebo-controlled or comparative, double-blind or investigator-blinded clinical trials, not including open label clinical trials, of treatment of multiple sclerosis (MS) with combination therapy or add-on therapy, including trials of induction therapy, trials for prevention of disease activity or worsening, amelioration of adverse effects, and treatment of relapses, and trials to increase remyelination.

EXPERT OPINION

Combination of two platform therapies (Interferon-beta or glatiramer acetate) was without additional effect. Clinical trials with add-on, often applying repurposed drugs (e.g. simvastatin, atorvastatin, minocycline, estriol, cyclophosphamide, azathioprine, albuterol, vitamin D), have been negative, apart from monthly methylprednisolone that, however, had low tolerability. Combination therapy for neuroprotection/remyelination showed some interesting results, though we are still awaiting results of phase III trials. The results of combination of anti-inflammatory therapies have in general been disappointing. In the future, combination of new effective neuroprotective/remyelinating drugs and highly effective anti-inflammatory treatments may benefit people with MS.

An Innovative Tool for Evidence-Based, Personalized Treatment Trials in Mucopolysaccharidosis

Mucopolysaccharidosis (MPS) is a group of rare metabolic diseases associated with reduced life expectancy and a substantial unmet medical need. Immunomodulatory drugs could be a relevant treatment approach for MPS patients, although they are not licensed for this population. Therefore, we aim to provide evidence justifying fast access to innovative individual treatment trials (ITTs) with immunomodulators and a high-quality evaluation of drug effects by implementing a risk-benefit model for MPS. The iterative methodology of our developed decision analysis framework (DAF) consists of the following steps: (i) a comprehensive literature analysis on promising treatment targets and immunomodulators for MPS; (ii) a quantitative risk-benefit assessment (RBA) of selected molecules; and (iii) allocation phenotypic profiles and a quantitative assessment. These steps allow for the personalized use of the model and are in accordance with expert and patient representatives. The following four promising immunomodulators were identified: adalimumab, abatacept, anakinra, and cladribine. An improvement in mobility is most likely with adalimumab, while anakinra might be the treatment of choice for patients with neurocognitive involvement. Nevertheless, a RBA should always be completed on an individual basis. Our evidence-based DAF model for ITTs directly addresses the substantial unmet medical need in MPS and characterizes a first approach toward precision medicine with immunomodulatory drugs.

Moving forward through the in silico modeling of multiple sclerosis: Treatment layer implementation and validation

Multiple sclerosis is an autoimmune inflammatory disease that affects the central nervous system through chronic demyelination and loss of oligodendrocytes. Since the relapsing-remitting form is the most prevalent, relapse-reducing therapies are a primary choice for specialists. Universal Immune System Simulator is an agent-based model that simulates the human immune system dynamics under physiological conditions and during several diseases, including multiple sclerosis. In this work, we extended the UISS-MS disease layer by adding two new treatments, i.e., cladribine and ocrelizumab, to show that UISS-MS can be potentially used to predict the effects of any existing or newly designed treatment against multiple sclerosis. To retrospectively validate UISS-MS with ocrelizumab and cladribine, we extracted the clinical and MRI data from patients included in two clinical trials, thus creating specific cohorts of digital patients for predicting and validating the effects of the considered drugs. The obtained results mirror those of the clinical trials, demonstrating that UISS-MS can correctly simulate the mechanisms of action and outcomes of the treatments. The successful retrospective validation concurred to confirm that UISS-MS can be considered a digital twin solution to be used as a support system to inform clinical decisions and predict disease course and therapeutic response at a single patient level.

Current Updates on the Diagnosis and Management of Multiple Sclerosis for the General Neurologist

Multiple sclerosis (MS) is an immune-driven disease that affects the central nervous system and is characterized by acute-on-chronic demyelination attacks. It is a major cause of global neurological disability, and its prevalence has increased in the United States. Conceptual understandings of MS have evolved over time, including the identification of B cells as key factors in its pathophysiology. The foundation of MS management involves preventing flares so as to avoid long-term functional decline. Treatments may be categorized into low-, middle-, and high-efficacy medications based on their efficacy in relapse prevention. With 24 FDA-approved treatments for MS, individual therapy is chosen based on distinct mechanisms and potential side effects. This review provides a detailed update on the epidemiology, diagnosis, treatment advances, and major ongoing research investigations in MS.

Oral Cladribine Impairs Intermediate, but Not Conventional, Monocyte Transmigration in Multiple Sclerosis Patients across a Model Blood-Brain Barrier

Multiple sclerosis (MS) is a disease in which the immune system damages components of the central nervous system (CNS), leading to the destruction of myelin and the formation of demyelinating plaques. This often occurs in episodic “attacks” precipitated by the transmigration of leukocytes across the blood-brain barrier (BBB), and repeated episodes of demyelination lead to substantial losses of axons within and removed from plaques, ultimately leading to progressive neurological dysfunction. Within leukocyte populations, macrophages and T and B lymphocytes are the predominant effectors. Among current immunotherapies, oral cladribine’s impact on lymphocytes is well characterised, but little is known about its impact on other leukocytes such as monocytes and dendritic cells (DCs). The aim of this study was to determine the transmigratory ability of monocyte and DC subsets in healthy subjects and untreated and cladribine-treated relapse-remitting MS (RRMS) patients using a well-characterised model of the BBB. Peripheral blood mononuclear cells from subjects were added to an in vitro transmigration assay to assess cell migration. Our findings show that while prior treatment with oral cladribine inhibits the migration of intermediate monocytes, it has no impact on the transmigration of DC subsets. Overall, our data indicate a previously unrecognised role of cladribine on intermediate monocytes, known to accumulate in the brain active MS lesions.

Platinum-Nucleos(t)ide Compounds as Possible Antimetabolites for Antitumor/Antiviral Therapy: Properties and Perspectives

Nucleoside analogues (NAs) are a family of compounds which include a variety of purine and pyrimidine derivatives, widely used as anticancer and antiviral agents. For their ability to compete with physiological nucleosides, NAs act as antimetabolites exerting their activity by interfering with the synthesis of nucleic acids. Much progress in the comprehension of their molecular mechanisms has been made, including providing new strategies for potentiating anticancer/antiviral activity. Among these strategies, new platinum-NAs showing a good potential to improve the therapeutic indices of NAs have been synthesized and studied. This short review aims to describe the properties and future perspectives of platinum-NAs, proposing these complexes as a new class of antimetabolites.

Lessons from immunotherapies in multiple sclerosis

The improved understanding of multiple sclerosis (MS) neurobiology alongside the development of novel markers of disease will allow precision medicine to be applied to MS patients, bringing the promise of improved care. Combinations of clinical and paraclinical data are currently used for diagnosis and prognosis. The addition of advanced magnetic resonance imaging and biofluid markers has been strongly encouraged, since classifying patients according to the underlying biology will improve monitoring and treatment strategies. For example, silent progression seems to contribute significantly more than relapses to overall disability accumulation, but currently approved treatments for MS act mainly on neuroinflammation and offer only a partial protection against neurodegeneration. Further research, involving traditional and adaptive trial designs, should strive to halt, repair or protect against central nervous system damage. To personalize new treatments, their selectivity, tolerability, ease of administration, and safety must be considered, while to personalize treatment approaches, patient preferences, risk-aversion, and lifestyle must be factored in, and patient feedback used to indicate real-world treatment efficacy. The use of biosensors and machine-learning approaches to integrate biological, anatomical, and physiological parameters will take personalized medicine a step closer toward the patient's virtual twin, in which treatments can be tried before they are applied.

Serum Neurofilament Light Chain as Biomarker for Cladribine-Treated Multiple Sclerosis Patients in a Real-World Setting

Serum neurofilament light chain (sNfL) is an intensely investigated biomarker in multiple sclerosis (MS). The aim of this study was to explore the impact of cladribine (CLAD) on sNfL and the potential of sNfL as a predictor of long-term treatment response. Data were gathered from a prospective, real-world CLAD cohort. We measured sNfL at baseline (BL-sNfL) and 12 months (12Mo-sNfL) after CLAD start by SIMOA. Clinical and radiological assessments determined fulfilment of "no evidence of disease activity" (NEDA-3). We evaluated BL-sNfL, 12M-sNfL and BL/12M sNfL ratio (sNfL-ratio) as predictors for treatment response. We followed 14 patients for a median of 41.5 months (range 24.0-50.0). NEDA-3 was fulfilled by 71%, 57% and 36% for a period of 12, 24 and 36 months, respectively. We observed clinical relapses in four (29%), MRI activity in six (43%) and EDSS progression in five (36%) patients. CLAD significantly reduced sNfL (BL-sNfL: mean 24.7 pg/mL (SD ± 23.8); 12Mo-sNfL: mean 8.8 pg/mL (SD ± 6.2); p = 0.0008). We found no correlation between BL-sNfL, 12Mo-sNfL and ratio-sNfL and the time until loss of NEDA-3, the occurrence of relapses, MRI activity, EDSS progression, treatment switch or sustained NEDA-3. We corroborate that CLAD decreases neuroaxonal damage in MS patients as determined by sNfL. However, sNfL at baseline and at 12 months failed to predict clinical and radiological treatment response in our real-world cohort. Long-term sNfL assessments in larger studies are essential to explore the predictive utility of sNfL in patients treated with immune reconstitution therapies.

Risk of cervical pre-cancer and cancer in women with multiple sclerosis exposed to high efficacy disease modifying therapies

There is a growing need to better understand the risk of malignancy in the multiple sclerosis (MS) population, particularly given the relatively recent and widespread introduction of immunomodulating disease modifying therapies (DMTs). Multiple sclerosis disproportionately affects women, and the risk of gynecological malignancies, specifically cervical pre-cancer and cancer, are of particular concern. The causal relationship between persistent human papillomavirus (HPV) infection and cervical cancer has been definitively established. To date, there is limited data on the effect of MS DMTs on the risk of persistent HPV infection and subsequent progression to cervical pre-cancer and cancer. This review evaluates the risk of cervical pre-cancer and cancer in women with MS, including the risk conferred by DMTs. We examine additional factors, specific to the MS population, that alter the risk of developing cervical cancer including participation in HPV vaccination and cervical screening programs.

Updates and advances in multiple sclerosis neurotherapeutics

The multiple sclerosis (MS) neurotherapeutic landscape is rapidly evolving. New disease-modifying therapies (DMTs) with improved efficacy and safety, in addition to an expanding pipeline of agents with novel mechanisms, provide more options for patients with MS. While treatment of MS neuroinflammation is well tailored in the existing DMT armamentarium, concerted efforts are currently underway for identifying neuropathological targets and drug discovery for progressive MS. There is also ongoing research to develop agents for remyelination and neuroprotection. Further insights are needed to guide DMT initiation and sequencing as well as to determine the role of autologous stem cell transplantation in relapsing and progressive MS. This review provides a summary of these updates.

Real-world experience of cladribine treatment in relapsing-remitting multiple sclerosis: A Danish nationwide study

BACKGROUND

Cladribine is a nucleoside analogue interfering with synthesis and repair of DNA. Treatment with cladribine leads to a preferential reduction in lymphocytes, resulting in profound depletion of B-cells with a rapid recovery of naïve B-cells, while T-cell show a lesser but long-lasting depletion It is approved for treatment of relapsing multiple sclerosis (MS). Cladribine tablets 3.5 mg/kg bodyweight are administered in two yearly treatment courses, each including two treatment series lasting 4 or 5 days, one at the start of the first month and the other at the start of the second month.

OBJECTIVE

To describe treatment patterns of cladribine in a real-world setting.

METHODS

Registry based observational cohort study with prospectively enrolled cases from December 2017 through June 2021. The data source is The Danish Multiple Sclerosis Registry, which is a near complete nationwide population-based registry. Outcomes were length of the treatment, preceding and following treatments, treatment response, and safety data.

RESULTS

In total 268 patients had started therapy with cladribine tablets, 89 men and 179 women, with a median age of 40 years (interquartile range (IQR) 32-48. The disease course was relapsing-remitting MS in 97.8% of the patients, and at treatment start the median time from disease onset was 8.1 years (IQR 4.2-14.5) and EDSS 2.5 (IQR 1.5-3.5). Thirty-four patients (12.7%) were treatment naïve while 56 (20.9%) had received one previous disease-modifying therapy (DMT), 67 (25.0%) two, and 111 (41.4%) three or more previous DMTs. In total, 214 (80.0%) patients had completed the full treatment of two courses of cladribine, while 54 (20.0%) had received only one course of cladribine tablets. The median follow-up time after cladribine initiation was 34.7 months (IQR 23.3-43.7). Compared with an annualized relapse rate (ARR) of 0.67 (95% CI [0.56, 0.79]) in the year prior to start of cladribine, ARR was reduced to 0.11 (95% CI [0.08, 0.15]) in year 0-2 after 3-month re-baseline with cladribine (84.8% reduction). Adverse events, reported in 44 (16.4%) of the patients, were mild or moderate, and herpes zoster was only reported in 2 patients. In total, 30 (11.2%) patients discontinued cladribine treatment, of whom 7 (2.6%) discontinued because of adverse effects and 12 (4.5%) discontinued because of disease activity.

CONCLUSION

In this nationwide review of all Danish patients starting therapy with cladribine tablets in a real-world setting, cladribine treatment was safe, and the therapeutic response was as expected from previous clinical trials. A prolonged observation period is necessary to assess the long-term benefit and risk of cladribine.

The effect of cladribine on immunoglobulin levels compared to B cell targeting therapies in multiple sclerosis

Background

Cladribine is a useful therapeutic option in RRMS with moderate to high disease activity. Its oral formulation and tolerability make it a useful alternative to infusion therapies. Cladribine is known to deplete CD19⁺ B lymphocytes, but its effect on immunoglobulin subsets is unclear.

Objective

To identify whether cladribine therapy in pwMS reduces immunoglobulin subset levels as a surrogate marker of infection risk.

Methods

A 'real-world' retrospective analysis of 341 pwMS presenting to a single tertiary centre between March 2017 and July 2021. Differences in immunoglobulin levels between cladribine, other disease-modifying therapies and no active treatment were assessed using a univariate ANOVA.

Results

Three hundred and forty-one patients had immunoglobulin levels assessed, with 29 patients treated with cladribine. The mean IgG, IgM and IgA levels on cladribine therapy were 10.44 ± 0.40, 0.99 ± 0.09 and 2.04 ± 0.18 g/L respectively. These were not significantly different from patients not on active treatment. There was a statistically significant reduction in IgG and IgM levels for patients treated with ocrelizumab (9.37 ± 0.19 and 0.68 ± 0.04 g/L) and natalizumab (8.72 ± 0.53 and 0.69 ± 0.12 g/L) compared to patients not on treatment.

Conclusion

Cladribine therapy for RRMS was not associated with immunoglobulin subset deficiencies. This is contrasted to ocrelizumab and natalizumab which demonstrate significant reductions in both IgG and IgM levels.

Targeting deoxycytidine kinase improves symptoms in mouse models of multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease driven by lymphocyte activation against myelin autoantigens in the central nervous system leading to demyelination and neurodegeneration. The deoxyribonucleoside salvage pathway with the rate-limiting enzyme deoxycytidine kinase (dCK) captures extracellular deoxyribonucleosides for use in intracellular deoxyribonucleotide metabolism. Previous studies have shown that deoxyribonucleoside salvage activity is enriched in lymphocytes and required for early lymphocyte development. However, specific roles for the deoxyribonucleoside salvage pathway and dCK in autoimmune diseases such as MS are unknown. Here we demonstrate that dCK activity is necessary for the development of clinical symptoms in the MOG35-55 and MOG1-125 experimental autoimmune encephalomyelitis (EAE) mouse models of MS. During EAE disease, deoxyribonucleoside salvage activity is elevated in the spleen and lymph nodes. Targeting dCK with the small molecule dCK inhibitor TRE-515 limits disease severity when treatments are started at disease induction or when symptoms first appear. EAE mice treated with TRE-515 have significantly fewer infiltrating leukocytes in the spinal cord, and TRE-515 blocks activation-induced B and T cell proliferation and MOG35-55 -specific T cell expansion without affecting innate immune cells or naïve T and B cell populations. Our results demonstrate that targeting dCK limits symptoms in EAE mice and suggest that dCK activity is required for MOG35-55 -specific lymphocyte activation-induced proliferation.

[New neuroimaging methods in assessing the activity of neuroinflammation in multiple sclerosis]

The review presents current data on the use of positron emission tomography and single-photon emission computed tomography in multiple sclerosis (MS) to assess the activity of the pathological process, including neuroinflammation, demyelination, activation of microglia, neurodegeneration and local blood flow disorders. These methodologies are a new approach for studying the mechanisms of action and evaluating the clinical effect of disease modifying therapy of MS, especially those capable of penetrating into brain tissue. Among them, the most attention is attracted by cladribine tablets acting on the mechanism of immune reconstitution therapy, most likely with the modulation of immune reactions directly in the brain tissue.

Cladribine treatment improves cortical network functionality in a mouse model of autoimmune encephalomyelitis

Background

Cladribine is a synthetic purine analogue that interferes with DNA synthesis and repair next to disrupting cellular proliferation in actively dividing lymphocytes. The compound is approved for the treatment of multiple sclerosis (MS). Cladribine can cross the blood–brain barrier, suggesting a potential effect on central nervous system (CNS) resident cells. Here, we explored compartment-specific immunosuppressive as well as potential direct neuroprotective effects of oral cladribine treatment in experimental autoimmune encephalomyelitis (EAE) mice.

Methods

In the current study, we compare immune cell frequencies and phenotypes in the periphery and CNS of EAE mice with distinct grey and white matter lesions (combined active and focal EAE) either orally treated with cladribine or vehicle, using flow cytometry. To evaluate potential direct neuroprotective effects, we assessed the integrity of the primary auditory cortex neuronal network by studying neuronal activity and spontaneous synaptic activity with electrophysiological techniques ex vivo.

Results

Oral cladribine treatment significantly attenuated clinical deficits in EAE mice. Ex vivo flow cytometry showed that cladribine administration led to peripheral immune cell depletion in a compartment-specific manner and reduced immune cell infiltration into the CNS. Histological evaluations revealed no significant differences for inflammatory lesion load following cladribine treatment compared to vehicle control. Single cell electrophysiology in acute brain slices was performed and showed an impact of cladribine treatment on intrinsic cellular firing patterns and spontaneous synaptic transmission in neurons of the primary auditory cortex. Here, cladribine administration in vivo partially restored cortical neuronal network function, reducing action potential firing. Both, the effect on immune cells and neuronal activity were transient.

Conclusions

Our results indicate that cladribine exerts a neuroprotective effect after crossing the blood–brain barrier independently of its peripheral immunosuppressant action.

Immunomodulators and immunosuppressants for progressive multiple sclerosis: a network meta‐analysis

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

We will perform a network meta‐analysis to assess the relative effectiveness and safety of immunomodulatory and immunosuppressive treatments for people with multiple sclerosis in progressive forms of the condition.

Therapeutic drug repositioning with special emphasis on neurodegenerative diseases: Threats and issues

Drug repositioning or repurposing is the process of discovering leading-edge indications for authorized or declined/abandoned molecules for use in different diseases. This approach revitalizes the traditional drug discovery method by revealing new therapeutic applications for existing drugs. There are numerous studies available that highlight the triumph of several drugs as repurposed therapeutics. For example, sildenafil to aspirin, thalidomide to adalimumab, and so on. Millions of people worldwide are affected by neurodegenerative diseases. According to a 2021 report, the Alzheimer's disease Association estimates that 6.2 million Americans are detected with Alzheimer's disease. By 2030, approximately 1.2 million people in the United States possibly acquire Parkinson's disease. Drugs that act on a single molecular target benefit people suffering from neurodegenerative diseases. Current pharmacological approaches, on the other hand, are constrained in their capacity to unquestionably alter the course of the disease and provide patients with inadequate and momentary benefits. Drug repositioning-based approaches appear to be very pertinent, expense- and time-reducing strategies for the enhancement of medicinal opportunities for such diseases in the current era. Kinase inhibitors, for example, which were developed for various oncology indications, demonstrated significant neuroprotective effects in neurodegenerative diseases. This review expounds on the classical and recent examples of drug repositioning at various stages of drug development, with a special focus on neurodegenerative disorders and the aspects of threats and issues viz. the regulatory, scientific, and economic aspects.

B-Cell Targeted Therapies in Patients with Multiple Sclerosis and Incidence of Headache: A Systematic Review and Meta-Analysis

Background: Multiple Sclerosis treatment with B-cell targeted therapies may be associated with an increased incidence of headache. We aimed to find and compare the association of B-cell targeted therapies with the incidence of headache in patients with Multiple Sclerosis. Methods: In a systematic based approach, the following databases were searched from inception until the 6th of June 2020: Pubmed/MEDLINE, ClinicalTrials.gov, EU Clinical Trials Register. Only randomized clinical trials (RCTs) enrolling patients with Multiple Sclerosis comparing B-cell targeted therapies (Rituximab, Ocrelizumab, Ofatumumab, Ublituximab or Cladribine) with placebo were selected for the systematic review and further meta-analysis. PRISMA guidelines were followed at all stages of the systematic review. The primary outcome was an all-cause headache of B-cell targeting therapy in patients with Multiple Sclerosis. Results: Nine RCTs were included. Compared with placebo, treatment with B-cell targeting therapies revealed a trend in headache risk, but it was not statistically significant (Relative Risk 1.12 [95% Confidence Interval 0.96–1.30]; p = 0.15; I² = 9.32%). Surprisingly, in a sub-group analysis, Cladribine was statistically significant for an increase in headache risk (RR 1.20 [95% CI 1.006–1.42]; p = 0.042; I² = 0%; 3 studies with 2107 participants). Conclusions: Even though a trend is shown, B-cell targeted therapies do not correlate with an increased incidence of headache as an adverse effect. Sub-analyses revealed a significant association between Cladribine alone and an increased incidence of headache. Whereas a purinergic signaling cascade is proposed as a mechanism of action, further research is needed to unravel the underlying pathogenetic mechanism of headache induction and establish headache prevention strategies.

Cytokine Secretion Dynamics of Isolated PBMC after Cladribine Exposure in RRMS Patients

Cladribine (CLD) treats multiple sclerosis (MS) by selectively and transiently depleting B and T cells with a secondary long-term reconstruction of the immune system. This study provides evidence of CLD’s immunomodulatory role in peripheral blood mononuclear cells (PBMCs) harvested from 40 patients with untreated relapsing-remitting MS (RRMS) exposed to CLD. We quantified cytokine secretion from PBMCs isolated by density gradient centrifugation with Ficoll−Paque using xMAP technology on a FlexMap 3D analyzer with a highly sensitive multiplex immunoassay kit. The PBMC secretory profile was evaluated with and without CLD exposure. PBMCs isolated from patients with RRMS for ≤12 months had significantly higher IL-4 but significantly lower IFN-γ and TNF-α secretion after CLD exposure. PBMCs isolated from patients with RRMS for >12 months had altered inflammatory ratios toward an anti-inflammatory profile and increased IL-4 but decreased TNF-α secretion after CLD exposure. CLD induced nonsignificant changes in IL-17 secretion in both RRMS groups. Our findings reaffirm CLD’s immunomodulatory effect that induces an anti-inflammatory phenotype.

Expert-Agreed Practical Recommendations on the Use of Cladribine

Cladribine is a disease-modifying selective immune reconstitution oral therapy for adult patients with highly active relapsing multiple sclerosis (RMS). It was approved in the USA in 2019 and in Europe in 2017, thus there are still gaps in existing guidelines for using cladribine tablets in clinical practice. Nine experts with extensive experience in managing patients with multiple sclerosis in Spain identified some of the unanswered questions related to the real-life use of cladribine tablets. They reviewed the available clinical trial data and real-world evidence, including their own experiences of using cladribine, over the course of three virtual meetings held between November 2020 and January 2021. This article gathers their practical recommendations to aid treatment decision-making and optimise the use of cladribine tablets in patients with RMS. The consensus recommendations cover the following areas: candidate patient profiles, switching strategies (to and from cladribine), managing response to cladribine and safety considerations.

Juvenile Idiopathic Arthritis, Uveitis and Multiple Sclerosis: Description of Two Patients and Literature Review

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood, while multiple sclerosis (MS) is a demyelinating disease of the central nervous system, characterized by remission and exacerbation phases. An association between MS and rheumatologic diseases, in particular rheumatoid arthritis, has been described and numerous studies acknowledge anti-TNF-α drugs as MS triggers. Conversely, the association between MS and JIA has been reported merely in five cases in the literature. We describe two cases of adult patients with longstanding JIA and JIA-associated uveitis, who developed MS. The first patient was on methotrexate and adalimumab when she developed dizziness and nausea. Characteristic MRI lesions and oligoclonal bands in cerebrospinal fluid led to MS diagnosis. Adalimumab was discontinued, and she was treated with three pulses of intravenous methylprednisolone. After a few months, rituximab was started. The second patient had been treated with anti-TNF-α and then switched to abatacept. She complained of unilateral arm and facial paraesthesias; brain MRI showed characteristic lesions, and MS was diagnosed. Three pulses of intravenous methylprednisolone were administered; neurological disease remained stable, and abatacept was reintroduced. Further studies are warranted to define if there is an association between JIA and MS, if MS represents JIA comorbidity or if anti-TNF-α underpins MS development.

Cladribine Tablets for Relapsing-Remitting Multiple Sclerosis: A Clinician's Review

Multiple sclerosis (MS) is a chronic neurodegenerative disease characterized by inflammation and demyelination for which there is currently no cure; therefore, the aim of therapy is to reduce the risk of relapse and disability progression. The treatment options for MS have increased greatly in recent years with the development of several disease-modifying therapies (DMTs) and the advent of immune reconstitution therapy (IRT). IRTs are administered in short-dosing periods to produce long-term effects on the immune system. Treatment with an IRT is based on the 3Rs: reduction, repopulation, and reconstitution of lymphocytes, which leads to restoration of immune effector functions. Cladribine tablets represent a selective, high-efficacy, oral form of IRT for patients with MS that targets lymphocytes and spares innate immune cells. Patients require only two weekly treatment courses, with each course comprising two treatment weeks, in Years 1 and 2; therefore, cladribine tablets are associated with a lower monitoring burden than many other DMTs, while short dosing periods can help to improve adherence. This review provides an overview of IRT and offers the clinician's perspective on the current MS treatment landscape, with a focus on practical advice for the management of patients undergoing treatment with cladribine tablets based on the most recent evidence available, including risks associated with COVID-19 and recommendations for vaccination in patients with MS.

Vaccination and immunotherapies in neuroimmunological diseases

Neuroimmunological diseases and their treatment compromise the immune system, thereby increasing the risk of infections and serious illness. Consequently, vaccinations to protect against infections are an important part of the clinical management of these diseases. However, the wide variety of immunotherapies that are currently used to treat neuroimmunological disease — particularly multiple sclerosis and neuromyelitis optica spectrum disorders — can also impair immunological responses to vaccinations. In this Review, we discuss what is known about the effects of various immunotherapies on immunological responses to vaccines and what these effects mean for the safe and effective use of vaccines in patients with a neuroimmunological disease. The success of vaccination in patients receiving immunotherapy largely depends on the specific mode of action of the immunotherapy. To minimize the risk of infection when using immunotherapy, assessment of immune status and exclusion of underlying chronic infections before initiation of therapy are essential. Selection of the required vaccinations and leaving appropriate time intervals between vaccination and administration of immunotherapy can help to safeguard patients. We also discuss the rapidly evolving knowledge of how immunotherapies affect responses to SARS-CoV-2 vaccines and how these effects should influence the management of patients on these therapies during the COVID-19 pandemic.

In this Review, the authors discuss how various immunotherapies for neuroimmunological diseases interact with vaccination responses, including responses to SARS-CoV-2 vaccinations, and the implications for the safe and effective use of vaccines in patients with these diseases.

Vaccination against infection is an essential part of the management of neuroimmunological diseases.

All indicated vaccinations should be administered before initiation of immunotherapy whenever possible; appropriate intervals between vaccination and treatment vary with treatment and vaccination.

Inactivated vaccines are considered safe in neuroimmunological diseases but live vaccines are generally contraindicated during immunotherapy.

Vaccination responses during immunotherapy can be diminished or abrogated, depending on the treatment and vaccination; antibody titre testing to monitor responses can be considered where appropriate.

Vaccinations must be avoided during relapses or exacerbations of neuroimmunological diseases.

Vaccination against SARS-CoV-2 is recommended for patients with neuroimmunological disease but some immunotherapies limit the immune response; therefore, timing should be considered carefully.

Integrated Lymphopenia Analysis in Younger and Older Patients With Multiple Sclerosis Treated With Cladribine Tablets

Cladribine tablets (CladT) preferentially reduce B and T lymphocyte levels. As aging is associated with a decline in immune function, the effect of CladT on lymphocyte levels may differ by age. This post hoc analysis combined data from the Phase 3 CLARITY, CLARITY Extension, and ORACLE-MS studies to examine the effect of age (≤50 or >50 years) on lymphopenia following CladT 3.5 mg/kg (CladT3.5; cumulative dose over 2 years) treatment over 96 weeks. Both CladT3.5 and placebo were given over Weeks 1 and 5 (Year 1 treatment) and Weeks 48 and 52 (Year 2 treatment) from the start of the studies. Absolute lymphocyte count (ALC) and levels of lymphocyte subsets were examined in 1564 patients (Age ≤50 [placebo: N=566; CladT3.5: N=813]; Age >50 [placebo: N=75; CladT3.5: N=110]). In both age groups, following CladT3.5 treatment, nadir for ALC occurred at Week 9 (8 weeks following start of Year 1 treatment) and Week 55 (7 weeks following start of Year 2 treatment) of the 96-week period; for CD19+ B lymphocytes, nadir occurred at Week 9 (Year 1) and Week 52 (Year 2). For CD4+ T lymphocytes, nadir occurred at Week 16 (Year 1) in both age groups, and at Weeks 60 and 72 (Year 2) in the Age ≤50 and >50 groups, respectively. Nadir for CD8+ T lymphocytes occurred at Week 16 (Year 1) and Week 72 (Year 2) in the Age ≤50 group and levels remained in the normal range; nadir occurred at Week 9 (Year 1) and Week 96 (Year 2) in the Age >50 group. Lymphocyte recovery began soon after nadir following CladT3.5 treatment and median levels reached normal range by end of the treatment year in both age groups. By Week 96, ~25% of patients treated with CladT3.5 reported ≥1 episode of Grade ≥3 lymphopenia (Gr≥3L). The rate of certain infections was numerically higher in older versus younger patients who experienced Gr≥3L. In conclusion, CladT3.5 had a similar effect on ALC and lymphocyte subsets in both younger and older patient groups.

Different Susceptibility of T and B Cells to Cladribine Depends On Their Levels of Deoxycytidine Kinase Activity Linked to Activation Status

Deoxycytidine kinase (dCK) and 5' deoxynucleotidase (NT5C2) are involved in metabolism of cladribine (2CdA), the immunomodulatory drug for multiple sclerosis; by mediating phosphorylation (activation) or phosphorolysis (deactivation) of 2CdA, respectively, these enzymes promote or prevent its accumulation in the cell, which leads to cell death. In particular, lymphocytes which present with a high intracellular dCK/NT5C2 ratio are more sensitive to 2CdA than other immune cells. We aim at determining if the expression of these enzymes and/or their activity differ in specific progenitor and mature immune cells and are influenced by cellular activation and/or exposure to 2CdA. Flow cytometry analysis showed no difference in dCK/NT5C2 ratio in progenitor and mature immune cells. 2CdA induced apoptosis in stimulated T and B cells and unstimulated B cells. dCK expression was enhanced by 2CdA at mRNA and protein levels in activated T cells and mRNA level in activated B cells. dCK activity, measured through an in-house luminescence release enzyme assay was higher in activated T and B cells, and such an increase was abrogated in activated B cells, but not T cells, upon exposure to 2CdA. These results reveal an important relationship between dCK activity and the effect of 2CdA on B and T cells, according to their activation status. Further study is warranted to evaluate whether dCK activity could, in the future, be a suitable predictive biomarker of lymphocyte response to 2CdA.

Humoral immune response and lymphocyte levels after complete vaccination against COVID-19 in a cohort of multiple sclerosis patients treated with cladribine tablets

BACKGROUND

Patients with multiple sclerosis (MS) receiving immunomodulatory drugs were excluded from clinical trials on COVID-19 vaccines. Therefore, data regarding the efficacy of COVID-19 vaccines to induce humoral immunity in MS patients treated with B- and T-cell depleting agents is urgently warranted. Cladribine tablets are a high-efficacy disease-modifying treatment that exerts its therapeutic effect via sustained but transient lymphocyte depletion.

AIM

We report humoral responses in a German cohort of MS patients treated with cladribine tablets.

METHODS

This retrospective analysis included patients ≥18 years who were treated with cladribine tablets for relapsing MS in the first or second year and were fully vaccinated against COVID-19. Two weeks after the second vaccination at the earliest, blood samples were obtained for the assessment of anti-SARS-CoV-2 IgG antibodies, lymphocyte counts, B-cells, CD4+ T-cells, and CD8+ T-cells. Anti-SARS-CoV-2 IgG antibodies were quantified with the LIAISON® SARS-CoV-2 TrimericS IgG assay. Positivity was defined at a cutoff value of 33.8 BAU/mL.

RESULTS

In total, 38 patients (73.7% female, aged 23-66 years) were included in the analysis. Ten patients (26.3%) were treatment-naïve before initiating treatment with cladribine tablets. Most patients (84.2%) received mRNA vaccines. The time between the last dose of cladribine tablets and vaccination ranged between 2 and 96 weeks. Six patients (15.8%) were vaccinated within 4 weeks of their last cladribine dose. All patients achieved positive anti-SARS-CoV-2 IgG antibody levels. Humoral immune response was independent of age, time of vaccination in relation to the last cladribine dose, lymphocyte counts as well as B- and T-cell counts.

CONCLUSIONS

Treatment with cladribine tablets did not impair humoral response to COVID-19 vaccination. Time since last cladribine dose, age, prior therapy, lymphocyte count as well as B- and T-cell counts had no effect on seropositivity of anti-SARS-CoV-2 IgG antibodies.

Position of Cladribine Tablets in the Management of Relapsing-Remitting Multiple Sclerosis: An Expert Narrative Review From the United Arab Emirates

The use of immune reconstitution therapies (IRT) in patients with relapsing-remitting multiple sclerosis (RRMS) is associated with a prolonged period of freedom from relapses in the absence of continuously applied therapy. Cladribine tablets is a disease-modifying treatment (DMT) indicated for highly active relapsing multiple sclerosis (MS) as defined by clinical or imaging features. Treatment with cladribine tablets is effective and well tolerated in patients with active MS disease and have a low burden of monitoring during and following treatment. In this article, an expert group of specialist neurologists involved in the care of patients with MS in the United Arab Emirates provides their consensus recommendations for the practical use of cladribine tablets according to the presenting phenotype of patients with RRMS. The IRT approach may be especially useful for patients with highly active MS insufficiently responsive to treatment with a first-line DMT, those who are likely to adhere poorly to a continuous therapeutic regimen, treatment-naïve patients with high disease activity at first presentation, or patients planning a family who are prepared to wait until at least 6 months after the end of treatment. Information available to date does not suggest an adverse interaction between cladribine tablets and COVID-19 infection. Data are unavailable at this time regarding the efficacy of COVID-19 vaccination in patients treated with cladribine tablets. Robust immunological responses to COVID-19 infection or to other vaccines have been observed in patients receiving this treatment, and treatment with cladribine tablets per se should not represent a barrier to this vaccination.

Einblicke in die Behandlung der Multiplen Sklerose mit Cladribin-Tabletten seit Beginn der COVID-19-Pandemie

Der Prävention von Infektionskrankheiten kommt bei der Multiplen Sklerose (MS) eine besondere Bedeutung zu, da diese den Krankheitsverlauf ungünstig beeinflussen können. Dies wird uns im Rahmen der COVID-19-Pandemie verdeutlicht, wo die SARS-CoV-2-Infektion als Auslöser von besonders schweren und prolongierten Schüben und klinischer Verschlechterung identifiziert werden konnte. Umso wichtiger ist es daher, den Einfluss der für die MS zugelassenen Immuntherapien auf eine etwaige Suszeptibilität für eine SARS-CoV-2-Infektion, den COVID-19-Krankheitsverlauf und das Impfansprechen zu verstehen. In dieser Übersichtsarbeit werden diese Punkte unter besonderer Berücksichtigung von Cladribin-Tabletten, einer für den hochaktiven MS-Verlauf zugelassenen Immunrekonstitutionstherapie, beleuchtet.

Lymphocyte Counts and Multiple Sclerosis Therapeutics: Between Mechanisms of Action and Treatment-Limiting Side Effects

Although the detailed pathogenesis of multiple sclerosis (MS) is not completely understood, a broad range of disease-modifying therapies (DMTs) are available. A common side effect of nearly every MS therapeutic agent is lymphopenia, which can be both beneficial and, in some cases, treatment-limiting. A sound knowledge of the underlying mechanism of action of the selected agent is required in order to understand treatment-associated changes in white blood cell counts, as well as monitoring consequences. This review is a comprehensive summary of the currently available DMTs with regard to their effects on lymphocyte count. In the first part, we describe important general information about the role of lymphocytes in the course of MS and the essentials of lymphopenic states. In the second part, we introduce the different DMTs according to their underlying mechanism of action, summarizing recommendations for lymphocyte monitoring and definitions of lymphocyte thresholds for different therapeutic regimens.

Model-informed assessment of ethnic sensitivity and dosage justification for Asian populations in the global clinical development and use of cladribine tablets

Cladribine tablets have been approved in many countries for the treatment of patients with various forms of relapsing multiple sclerosis (MS). Cladribine has a unique pharmacokinetic/pharmacodynamic (PK/PD) profile with a short elimination half‐life (~ 1 day) relative to a prolonged PD effect on specific immune cells (most notably a reversible reduction in B and T lymphocyte counts). This results in a short dosing schedule (up to 20 days over 2 years of treatment) to sustain efficacy for at least another 2 years. Global clinical studies were conducted primarily in White patients, in part due to the distinctly higher prevalence of MS in White patients. Given the very low prevalence in Asian countries, MS is considered as a rare disease there. In spite of the limited participation of Asian patients, to demonstrate favorable benefit/risk profile in the treatment of MS demanded application of a Totality of Evidence approach to assess ethnic sensitivity for informing regulatory filings in Asian countries and supporting clinical use of cladribine in Asian patients. Population PD modeling and simulation of treatment‐related reduction in absolute lymphocyte count, as a mechanism‐related biomarker of drug effect, confirmed consistent PDs in Asian and non‐Asian patients with MS, supporting absence of ethnic sensitivity and a common dosage across populations. Through this example, we demonstrate the value of holistic integration of all available data using a model‐informed drug development (MIDD) framework and a Totality of Evidence mindset to evaluate ethnic sensitivity in support of Asia‐inclusive development and use of the drug across populations.

Immunosuppression in Multiple Sclerosis and Other Neurologic Disorders

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by peripheral immune cell infiltration into the brain and spinal cord, demyelination, glial cell activation, and neuronal damage. Currently there is no cure for MS, however, available disease-modifying agents minimize inflammation in the CNS by various mechanisms. Approved drugs lessen severity of the disease and delay disease progression, however, they are still suboptimal as patients experience adverse effects and varying efficacies. Additionally, there is only one disease-modifying therapy available for the more debilitating, progressive form of MS. This chapter focuses on the presently-available therapeutics and, importantly, the future directions of MS therapy based on preclinical studies and early clinical trials. Immunosuppression in other neurological disorders including neuromyelitis optica spectrum disorders, myasthenia gravis, and Guillain-Barré syndrome is also discussed.

Headache in multiple sclerosis - pharmacological aspects

For decades, headache was not considered a typical symptom of multiple sclerosis (MS) and was construed as a "red flag" for important differential diagnoses such as cerebral vasculitis. Meanwhile, several studies have demonstrated an increased prevalence of headache in MS compared to the general population. This is due to the heterogeneity of headache genesis with frequent occurrence of both primary and secondary headaches in MS. On the one hand, MS and migraine are often comorbid. On the other hand, secondary headaches occur frequently, especially in the course of MS relapses. These are often migraine-like headaches caused by inflammation, which can improve as a result of MS-specific therapy. Headaches are particularly common in the early stages of chronic inflammatory CNS disease, where inflammatory activity is greatest. In addition, headache can also occur as a side effect of disease-modifying drugs (DMDs). Headache can occur with most DMDs and is most frequently described with interferon-beta therapy. The aim of this work is to present the prevalence of headache and describe the heterogeneity of possible causes of headache in MS. In addition, important therapeutic aspects in the treatment of MS patients in general will be presented as well as different approaches to the treatment of headache in MS depending on the etiological classification.

Acting centrally or peripherally: A renewed interest in the central nervous system penetration of disease-modifying drugs in multiple sclerosis

With the recent approval of cladribine tablets, siponimod and ozanimod, there has been a renewed interest into the extent to which these current generation disease-modifying therapies (DMTs) are able to cross into the central nervous system (CNS), and how this penetration of the blood-brain barrier (BBB) may influence their ability to treat multiple sclerosis (MS). The integrity of the CNS is maintained by the BBB, blood-cerebrospinal fluid barrier, and the arachnoid barrier, which all play an important role in preserving the immunological environment and homeostasis within the CNS. The integrity of the BBB decreases during the course of MS, with a putative temporal relationship to disease worsening. Furthermore, it is currently considered that progression of the disease is mediated mainly by resident cells of the CNS. The existing literature provides evidence to show that some of the current generation DMTs for MS are able to penetrate the CNS and potentially exert direct effects on CNS-resident cells, in particular the CNS-penetrating prodrugs cladribine and fingolimod, and other sphingosine-1 phosphate receptor modulators; siponimod and ozanimod. Other current generation DMTs appear to be restricted to the periphery due to their high molecular weight or physicochemical properties. As more effective brain penetrant therapies are developed for the treatment of MS, there is a need to understand whether the potential for direct effects within the CNS are of significance, and whether this brings additional benefits over and above treatment effects mediated in the periphery. In turn, this will require an improved understanding of the structure and function of the BBB, the role it plays in MS and subsequent treatments. This narrative review summarizes the data supporting the biological plausibility of a potential benefit from therapeutic molecules entering the CNS, and discusses the potential significance in the current and future treatment of MS.