The treatment of chronic progressive multiple sclerosis with cladribine

Disease modifying treatment guidelines for multiple sclerosis in the United Arab Emirates

The newly constituted National Multiple Sclerosis (MS) Society (NMSS)of the United Arab Emirates (UAE), set up a scientific committee to create a MS disease modifying treatment (DMT) guideline for UAE. The committee considered several unique features of the MS community in UAE including large number of expatriate population, wide variations in health insurance coverage, physician and patient preferences for DMT. The overall goal of the treatment guideline is to facilitate the most appropriate DMT to the widest number of patients. To this end it has adapted recommendations from various health systems and regulatory authorities into a pragmatic amalgamation of best practices from across the world. Importantly where data is unavailable or controversial, a common sense approach is taken rather than leave physicians and patients in limbo. The committee classifies MS into subcategories and suggests appropriate treatment choices. It recommends treatment of RIS and CIS with poor prognostic factors. It largely equates the efficacy and safety of DMT with similar mechanisms of action or drug classes e.g. ocrelizumab is similar to rituximab. It allows early switching of treatment for unambiguous disease activity and those with progression independent of relapses. Autologous hematopoietic stem cell transplantation can be offered to patients who fail one high efficacy DMT. Pragmatic guidance on switching and stopping DMT, DMT choices in pregnancy, lactation and pediatric MS have been included. It is expected that these guidelines will be updated periodically as new data becomes available.

Dynamic disability measures decrease the clinico-radiological gap in people with severely affected multiple sclerosis

BACKGROUND

Expanded Disability Status Scale (EDSS) is limited when utilized in highly disabled people with multiple sclerosis (pwMS).

OBJETIVE

To explore the relationship between disability measures and MRI outcomes in severely-affected pwMS.

METHODS

PwMS recruited from The Boston Home (TBH), a specialized residential facility for severly-affected pwMS and University at Buffalo (UB) MS Center were assessed using EDSS, MS Severity Scale, age-related MSS, Scripps Neurological Rating Scale (SNRS) and Combinatorial Weight-Adjusted Disability Score (CombiWISE). In all scores except SNRS, higher score indicates greater disability. MRI measures of T1, T2-lesion volume (LV), whole brain, gray matter, medulla oblongata and thalamic volumes (WBV, GMV, MOV, TV) and thalamic dysconnectivity were obtained.

RESULTS

Greatest disability differences between the TBH and UB pwMS were in SNRS (24.4 vs 71.9, p < 0.001, Cohen's d = 4.05) and CombiWISE (82.3 vs. 38.9, p < 0.001, Cohen's d = 4.02). In combined analysis of all pwMS, worse SNRS scores were correlated with worse MRI pathology in 8 out of 9 outcomes. EDSS only with 3 measures (GMV, MOV and TV). In severely-affected pwMS, SNRS was associated with T1-LV, T2-LV and WBV (not surviving false discovery rate (FDR) correction for multiple comparisons) whereas EDSS did not.

CONCLUSION

Granular and dynamic disability measures may bridge the clinico-radiologcal gap present in severely affected pwMS.

Adverse effects of immunotherapies for multiple sclerosis: a network meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a chronic disease of the central nervous system that affects mainly young adults (two to three times more frequently in women than in men) and causes significant disability after onset. Although it is accepted that immunotherapies for people with MS decrease disease activity, uncertainty regarding their relative safety remains.

OBJECTIVES

To compare adverse effects of immunotherapies for people with MS or clinically isolated syndrome (CIS), and to rank these treatments according to their relative risks of adverse effects through network meta-analyses (NMAs).

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, two other databases and trials registers up to March 2022, together with reference checking and citation searching to identify additional studies.

SELECTION CRITERIA

We included participants 18 years of age or older with a diagnosis of MS or CIS, according to any accepted diagnostic criteria, who were included in randomized controlled trials (RCTs) that examined one or more of the agents used in MS or CIS, and compared them versus placebo or another active agent. We excluded RCTs in which a drug regimen was compared with a different regimen of the same drug without another active agent or placebo as a control arm.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for data extraction and pairwise meta-analyses. For NMAs, we used the netmeta suite of commands in R to fit random-effects NMAs assuming a common between-study variance. We used the CINeMA platform to GRADE the certainty of the body of evidence in NMAs. We considered a relative risk (RR) of 1.5 as a non-inferiority safety threshold compared to placebo. We assessed the certainty of evidence for primary outcomes within the NMA according to GRADE, as very low, low, moderate or high.

MAIN RESULTS

This NMA included 123 trials with 57,682 participants. Serious adverse events (SAEs) Reporting of SAEs was available from 84 studies including 5696 (11%) events in 51,833 (89.9%) participants out of 57,682 participants in all studies. Based on the absolute frequency of SAEs, our non-inferiority threshold (up to a 50% increased risk) meant that no more than 1 in 18 additional people would have a SAE compared to placebo. Low-certainty evidence suggested that three drugs may decrease SAEs compared to placebo (relative risk [RR], 95% confidence interval [CI]): interferon beta-1a (Avonex) (0.78, 0.66 to 0.94); dimethyl fumarate (0.79, 0.67 to 0.93), and glatiramer acetate (0.84, 0.72 to 0.98). Several drugs met our non-inferiority criterion versus placebo: moderate-certainty evidence for teriflunomide (1.08, 0.88 to 1.31); low-certainty evidence for ocrelizumab (0.85, 0.67 to 1.07), ozanimod (0.88, 0.59 to 1.33), interferon beta-1b (0.94, 0.78 to 1.12), interferon beta-1a (Rebif) (0.96, 0.80 to 1.15), natalizumab (0.97, 0.79 to 1.19), fingolimod (1.05, 0.92 to 1.20) and laquinimod (1.06, 0.83 to 1.34); very low-certainty evidence for daclizumab (0.83, 0.68 to 1.02). Non-inferiority with placebo was not met due to imprecision for the other drugs: low-certainty evidence for cladribine (1.10, 0.79 to 1.52), siponimod (1.20, 0.95 to 1.51), ofatumumab (1.26, 0.88 to 1.79) and rituximab (1.01, 0.67 to 1.52); very low-certainty evidence for immunoglobulins (1.05, 0.33 to 3.32), diroximel fumarate (1.05, 0.23 to 4.69), peg-interferon beta-1a (1.07, 0.66 to 1.74), alemtuzumab (1.16, 0.85 to 1.60), interferons (1.62, 0.21 to 12.72) and azathioprine (3.62, 0.76 to 17.19). Withdrawals due to adverse events Reporting of withdrawals due to AEs was available from 105 studies (85.4%) including 3537 (6.39%) events in 55,320 (95.9%) patients out of 57,682 patients in all studies. Based on the absolute frequency of withdrawals, our non-inferiority threshold (up to a 50% increased risk) meant that no more than 1 in 31 additional people would withdraw compared to placebo. No drug reduced withdrawals due to adverse events when compared with placebo. There was very low-certainty evidence (meaning that estimates are not reliable) that two drugs met our non-inferiority criterion versus placebo, assuming an upper 95% CI RR limit of 1.5: diroximel fumarate (0.38, 0.11 to 1.27) and alemtuzumab (0.63, 0.33 to 1.19). Non-inferiority with placebo was not met due to imprecision for the following drugs: low-certainty evidence for ofatumumab (1.50, 0.87 to 2.59); very low-certainty evidence for methotrexate (0.94, 0.02 to 46.70), corticosteroids (1.05, 0.16 to 7.14), ozanimod (1.06, 0.58 to 1.93), natalizumab (1.20, 0.77 to 1.85), ocrelizumab (1.32, 0.81 to 2.14), dimethyl fumarate (1.34, 0.96 to 1.86), siponimod (1.63, 0.96 to 2.79), rituximab (1.63, 0.53 to 5.00), cladribine (1.80, 0.89 to 3.62), mitoxantrone (2.11, 0.50 to 8.87), interferons (3.47, 0.95 to 12.72), and cyclophosphamide (3.86, 0.45 to 33.50). Eleven drugs may have increased withdrawals due to adverse events compared with placebo: low-certainty evidence for teriflunomide (1.37, 1.01 to 1.85), glatiramer acetate (1.76, 1.36 to 2.26), fingolimod (1.79, 1.40 to 2.28), interferon beta-1a (Rebif) (2.15, 1.58 to 2.93), daclizumab (2.19, 1.31 to 3.65) and interferon beta-1b (2.59, 1.87 to 3.77); very low-certainty evidence for laquinimod (1.42, 1.01 to 2.00), interferon beta-1a (Avonex) (1.54, 1.13 to 2.10), immunoglobulins (1.87, 1.01 to 3.45), peg-interferon beta-1a (3.46, 1.44 to 8.33) and azathioprine (6.95, 2.57 to 18.78); however, very low-certainty evidence is unreliable. Sensitivity analyses including only studies with low attrition bias, drug dose above the group median, or only patients with relapsing remitting MS or CIS, and subgroup analyses by prior disease-modifying treatments did not change these figures. Rankings No drug yielded consistent P scores in the upper quartile of the probability of being better than others for primary and secondary outcomes.

AUTHORS' CONCLUSIONS

We found mostly low and very low-certainty evidence that drugs used to treat MS may not increase SAEs, but may increase withdrawals compared with placebo. The results suggest that there is no important difference in the occurrence of SAEs between first- and second-line drugs and between oral, injectable, or infused drugs, compared with placebo. Our review, along with other work in the literature, confirms poor-quality reporting of adverse events from RCTs of interventions. At the least, future studies should follow the CONSORT recommendations about reporting harm-related issues. To address adverse effects, future systematic reviews should also include non-randomized studies.

Disease activity in primary progressive multiple sclerosis: a systematic review and meta-analysis

Background

Disease activity in multiple sclerosis (MS) is defined as presence of relapses, gadolinium enhancing lesions and/or new or enlarging lesions on MRI. It is associated with efficacy of immunomodulating therapies (IMTs) in primary progressive MS (PPMS). However, a thorough review on disease activity in PPMS is lacking. In relapsing remitting MS, the prevalence of activity decreases in more contemporary cohorts. For PPMS, this is unknown.

Aim

To review disease activity in PPMS cohorts and identify its predictors.

Methods

A systematic search in EMBASE, MEDLINE, Web of science Core Collection, COCHRANE CENTRAL register of trials, and GOOGLE SCHOLAR was performed. Keywords included PPMS, inflammation, and synonyms. We included original studies with predefined available data, extracted cohort characteristics and disease activity outcomes and performed meta-regression analyses.

Results

We included 34 articles describing 7,109 people with PPMS (pwPPMS). The weighted estimated proportion of pwPPMS with overall disease activity was 26.8% (95% CI 20.6-34.0%). A lower age at inclusion predicted higher disease activity (OR 0.91, p = 0.031). Radiological activity (31.9%) was more frequent than relapses (9.2%), and was predicted by longer follow-up duration (OR 1.27, p = 0.033). Year of publication was not correlated with disease activity.

Conclusion

Inflammatory disease activity is common in PPMS and has remained stable over the last decades. Age and follow-up duration predict disease activity, advocating prolonged monitoring of young pwPPMS to evaluate potential IMT benefits.

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.

Molecular and neuroimmune pharmacology of S1P receptor modulators and other disease-modifying therapies for multiple sclerosis

Multiple sclerosis (MS) is a neurological, immune-mediated demyelinating disease that affects people in the prime of life. Environmental, infectious, and genetic factors have been implicated in its etiology, although a definitive cause has yet to be determined. Nevertheless, multiple disease-modifying therapies (DMTs: including interferons, glatiramer acetate, fumarates, cladribine, teriflunomide, fingolimod, siponimod, ozanimod, ponesimod, and monoclonal antibodies targeting ITGA4, CD20, and CD52) have been developed and approved for the treatment of MS. All the DMTs approved to date target immunomodulation as their mechanism of action (MOA); however, the direct effects of some DMTs on the central nervous system (CNS), particularly sphingosine 1-phosphate (S1P) receptor (S1PR) modulators, implicate a parallel MOA that may also reduce neurodegenerative sequelae. This review summarizes the currently approved DMTs for the treatment of MS and provides details and recent advances in the molecular pharmacology, immunopharmacology, and neuropharmacology of S1PR modulators, with a special focus on the CNS-oriented, astrocyte-centric MOA of fingolimod.

Solute Carrier Nucleoside Transporters in Hematopoiesis and Hematological Drug Toxicities: A Perspective

Simple Summary

Anticancer nucleoside analogs are promising treatments that often result in damaging toxicities and therefore ineffective treatment. Mechanisms of this are not well-researched, but cellular nucleoside transport research in mice might provide additional insight given transport’s role in mammalian hematopoiesis. Cellular nucleoside transport is a notable component of mammalian hematopoiesis due to how mutations within it relate to hematological abnormities. This review encompasses nucleoside transporters, focusing on their inherent properties, hematopoietic role, and their interplay in nucleoside drug treatment side effects. We then propose potential mechanisms to explain nucleoside transport involvement in blood disorders. Finally, we point out and advocate for future research areas that would improve therapeutic outcomes for patients taking nucleoside analog therapies.

Abstract

Anticancer nucleoside analogs produce adverse, and at times, dose-limiting hematological toxicities that can compromise treatment efficacy, yet the mechanisms of such toxicities are poorly understood. Recently, cellular nucleoside transport has been implicated in normal blood cell formation with studies from nucleoside transporter-deficient mice providing additional insights into the regulation of mammalian hematopoiesis. Furthermore, several idiopathic human genetic disorders have revealed nucleoside transport as an important component of mammalian hematopoiesis because mutations in individual nucleoside transporter genes are linked to various hematological abnormalities, including anemia. Here, we review recent developments in nucleoside transporters, including their transport characteristics, their role in the regulation of hematopoiesis, and their potential involvement in the occurrence of adverse hematological side effects due to nucleoside drug treatment. Furthermore, we discuss the putative mechanisms by which aberrant nucleoside transport may contribute to hematological abnormalities and identify the knowledge gaps where future research may positively impact treatment outcomes for patients undergoing various nucleoside analog therapies.

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.

The Development of Cladribine Tablets for the Treatment of Multiple Sclerosis: A Comprehensive Review

Cladribine is a purine nucleoside analog initially developed in the 1970s as a treatment for various blood cancers. Due to the molecule’s ability to preferentially reduce T and B lymphocytes, it has been developed into an oral formulation for the treatment of multiple sclerosis (MS). The unique proposed mechanism of action of cladribine allows for the therapy to be delivered orally over two treatment-week cycles per year, one cycle at the beginning of the first month and one cycle at the beginning of the second month of years 1 and 2, with the potential for no further cladribine treatment required in years 3 and 4. This review summarizes the clinical development program for cladribine tablets in patients with MS, including the efficacy endpoints and results from the 2-year phase III CLARITY study in patients with relapsing–remitting MS (RRMS), the 2-year CLARITY EXTENSION study, and the phase III ORACLE-MS study in patients with a first clinical demyelinating event at risk for developing MS. Efficacy results from the phase II ONWARD study, in which cladribine tablets were administered as an add-on to interferon-β therapy in patients with RRMS, are also summarized. A review of all safety data, including lymphopenia, infections, and malignancies, is provided based on data from all trials in patients with MS, including the initial parenteral formulation studies. Based on these data, cladribine tablets administered at 3.5 mg/kg over 2 years have been approved across the globe for various forms of relapsing MS.

Oral pulsed therapy of relapsing multiple sclerosis with cladribine tablets - expert opinion on issues in clinical practice

BACKGROUND

Oral cladribine is the first oral pulsed therapy licensed for relapsing multiple sclerosis (RMS). Three years after the introduction into the European market, we evaluated practical aspects in the use of cladribine tablets, incorporating the experience gained in routine clinical practice and real-world studies.

METHODS

Based on a structured review process, a panel of nine neurologists experienced in MS therapy discussed salient statements regarding the use of cladribine tables. For each statement the level of evidence was determined according to the levels of evidence recommended by the Centre for Evidence-Based Medicine, Oxford. The strength of each expert statement was then evaluated by means of a linear scale from 1 (very strong rejection) to 9 (very strong approval). Votes were collected by a formalized blinded process. Consent was considered to be reached if at least 75% of the experts agreed on a particular statement (i.e. voted for 7-9 points on the linear scale).

RESULTS

. Statements include efficacy in early RMS, risk of side effects and infections, vaccination, pregnancy, and monitoring requirements.

CONCLUSION

The consented recommendations summarize the practical experience inthe use of cladribine tablets in a real-world setting. These may provide guidance for unanswered questions arising with the introduction of new treatments such as cladribine tablets.

The development and impact of cladribine on lymphoid and myeloid cells in multiple sclerosis

Cladribine is an approved selective immune reconstitution therapy for relapsing-remitting MS (RRMS). It was first developed and used to treat various forms of cancer, particularly leukemia via parenteral administration. The oral tablet version of cladribine was later developed to treat RRMS, an autoimmune disorder of the central nervous system (CNS) with periods of relapse and remission. Cladribine is found to selectively deplete adaptive immune cell types, and its role on innate immune cells is largely unknown. Among the lymphocyte populations and subtypes, the magnitude and kinetics of depletion by cladribine vary substantially. The current consensus on the selective cytotoxic effect of cladribine is that it is dependent on the deoxycytidine kinase (DCK) to 5'nucleotidase (5-NT) ratio of the immune cell type. Nonetheless, there are some discrepancies that cannot be fully elucidated by the DCK:5-NT ratio paradigm. This review aims to delineate the development and pharmacological properties of cladribine, and elucidate its influence on lymphoid and myeloid cells in MS.

[Disease-modifying treatment of secondary progressive multiple sclerosis]

BACKGROUND

Multiple sclerosis (MS) is a disease continuum from a clinically isolated syndrome through relapsing remitting MS to secondary progressive MS (SPMS). There are numerous therapeutic approaches with proven efficacy on relapse and focal inflammatory disease aspects, whereas treatment of secondary progression and associated neuropathological aspects continues to be a challenge.

OBJECTIVE

Overview of the current options for disease-modifying treatment of SPMS.

MATERIAL AND METHODS

Results of randomized clinical trials are presented and evaluated on a substance-specific basis.

RESULTS

Randomized SPMS trials showed inconsistent results regarding disability progression for beta interferons and negative results for natalizumab. Oral cladribine and ocrelizumab reduced disability progression in relapsing MS but have not been specifically studied in an SPMS population. Positive results for mitoxantrone are only partially applicable to current SPMS patients. For siponimod, a substance that crosses the blood-brain barrier, the EXPAND trial demonstrated a significant reduction in the risk of disability progression in typical SPMS. Subgroup analyses suggest a higher efficacy of siponimod in younger patients with active SPMS.

CONCLUSION

There is limited evidence for the use of previously available disease-modifying treatment in SPMS. Siponimod represents a new therapeutic option for active SPMS, defined by relapses or focal inflammatory MRI activity. To establish the therapeutic indications for siponimod, early detection of relapse-independent progression as well as differentiation of active SPMS from inactive disease are of critical importance.

Recent advances and remaining questions of autologous hematopoietic stem cell transplantation in multiple sclerosis

The judicious use of autologous hematopoietic stem cell transplantation (AHSCT) for MS requires understanding the potential benefits, identifying the most appropriate patient, and acknowledging the risks and differences between different protocols. Recently, AHSCT for MS is occurring more frequently, with a better safety profile than earlier studies. This review assesses recently published studies to determine the advances that have been made and remaining questions that future studies are poised to answer. We included studies from January 2016 to November 2020 with 20 or more patients. The benefits of AHSCT, including "no evidence of disease activity", functional and patient-reported outcomes, novel biomarkers such as brain atrophy or neurofilament light chain, and cost-effectiveness were assessed. The patient selection, treatment protocols, and safety outcomes differ between reports. The overall efficacy of AHSCT is better than standard treatments. Younger patients with highly active disease have greater chance for improvement, while patients who have comorbidities, failed more treatments, and are transitioning to a more progressive phase may not respond as well to AHSCT. The safety profiles for all AHSCT protocols is improving, however the durability of treatment response may not be the same for all protocols. The goal of AHSCT is to stop disease activity, avoid worsening disability, and obviate the need for further disease-modifying treatment, while improving patient quality of life and minimizing treatment-related risk. Results from currently enrolling randomized controlled trials, as well as ongoing registries, will provide more evidence for the safe and appropriate use of AHSCT.

Immunology of COVID-19 and disease-modifying therapies: The good, the bad and the unknown

Objective

The outbreak of the SARS‐CoV‐2 pandemic, caused by a previously unknown infectious agent, posed unprecedented challenges to healthcare systems and unmasked their vulnerability and limitations worldwide. Patients with long‐term immunomodulatory/suppressive therapies, as well as their physicians, were and are concerned about balancing the risk of infection and effects of disease‐modifying therapy. Over the last few months, knowledge regarding SARS‐CoV‐2 has been growing tremendously, and the first experiences of infections in patients with multiple sclerosis (MS) have been reported.

Methods

This review summarizes the currently still limited knowledge about SARS‐CoV‐2 immunology and the commonly agreed modes of action of approved drugs in immune‐mediated diseases of the central nervous system (MS and neuromyelitis optica spectrum disorder). Specifically, we discuss whether immunosuppressive/immunomodulatory drugs may increase the risk of SARS‐CoV‐2 infection and, conversely, may decrease the severity of a COVID‐19 disease course.

Results

At present, it can be recommended in general that none of those therapies with a definite indication needs to be stopped per se. A possibly increased risk of infection for most medications is accompanied by the possibility to reduce the severity of COVID‐19.

Conclusions

Despite the knowledge gain over the last few months, current evidence remains limited, and, thus, further clinical vigilance and systematic documentation is essential.

Treatment Optimization in Multiple Sclerosis: Canadian MS Working Group Recommendations

The Canadian Multiple Sclerosis Working Group has updated its treatment optimization recommendations (TORs) on the optimal use of disease-modifying therapies for patients with all forms of multiple sclerosis (MS). Recommendations provide guidance on initiating effective treatment early in the course of disease, monitoring response to therapy, and modifying or switching therapies to optimize disease control. The current TORs also address the treatment of pediatric MS, progressive MS and the identification and treatment of aggressive forms of the disease. Newer therapies offer improved efficacy, but also have potential safety concerns that must be adequately balanced, notably when treatment sequencing is considered. There are added discussions regarding the management of pregnancy, the future potential of biomarkers and consideration as to when it may be prudent to stop therapy. These TORs are meant to be used and interpreted by all neurologists with a special interest in the management of MS.

Efficacy and Safety of Intravenous Cladribine in Patients with Rapidly Evolving or Early Secondary Progressive Multiple Sclerosis

Background

Multiple sclerosis (MS) is an autoimmune and demyelinating inflammatory disease that affects the central nervous system (CNS). The etiology of the disease remains unknown. Multiple theories highlight genetic, environmental, and infectious factors that may a role. MS is considered as the main cause of disability in young people. Cladribine, known chemically as (2-Chloro-2′-deoxyadenosine), is a purine analog chemotherapy used for hairy cell leukemia and other B-cell lymphomas. The goal of this study was to evaluate the safety and efficacy of cladribine in patients with rapidly evolving or early secondary progressive MS.

Methods

This observational, single-center, retrospective chart review at the MS Clinic in the Ottawa General Hospital, Ottawa, Canada. A total of 24 patients (median Expanded Disability Status Scale (EDSS) of 4.5) received cladribine (0.07 mg/kg/day) for four consecutive days every six months for ≥ 2 cycles with further cycles depending on lymphocyte recovery or disease activity to a maximum of eight cycles from 2005 until 2016 were included. Four patients who were already diagnosed with rapidly evolving or early secondary progressive multiple sclerosis (SPMS) were induced with cladribine. We evaluated relapse, EDSS, and magnetic resonance imaging (MRI) results.

Results

Out of 24 patients (ages ranging from 30 - 60), 80% were female. Median follow-up time was seven years. The mean relapse rate in the two years before patients were given cladribine was 1.25. Twenty patients had previously received multiple disease-modifying therapies (DMTs) (≥ 2) prior to receiving cladribine. Following cladribine, eight patients suffered 10 relapses (33.3% of the cohort). Annualized relapse rates (ARRs) were reduced from 1.25 to 0.42, which was statistically significant (p-value = 0.002). There was no mean difference in EDSS (p-value = 0.06): 16% deteriorated, 62% did not change, and 12.5% improved. New MRI activity (new T2 or Gad+ lesions) was noted in only seven of 24 patients. 

Conclusion

Parenteral cladribine reduced the relapse rate from 1.25 to 0.42, which was statistically significant (p-value = 0.002). MRI activity in patients with rapidly evolving or early secondary progressive multiple sclerosis had a reasonable safety profile. 

Consensus recommendations for the diagnosis and treatment of multiple sclerosis: 2019 revisions to the MENACTRIMS guidelines

With evolving diagnostic criteria and the advent of new oral and parenteral therapies for 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 in 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 multiple sclerosis (MS) therapies is critical to maximize patient benefit. The current guidelines review the scientific evidence supporting treatment of acute relapses, radiologically isolated syndrome, clinically isolated syndrome, relapsing remitting MS, and progressive MS. 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.

Plasma cell and B cell-targeted treatments for use in advanced multiple sclerosis

There is increasing evidence that agents that target peripheral B cells and in some instances plasma cells can exhibit marked effects on relapsing multiple sclerosis. In addition, B cells, including plasma cells, within the central nervous system compartment are likely to play an important role in disease progression in both relapsing and progressive MS. However, current B cell-targeting antibodies may not inhibit these, because of poor penetration into the central nervous system and often oligoclonal bands of immunoglobulin persist within the cerebrospinal fluid despite immunotherapy. Through targeting B cells and plasma cells in the CNS, it may be possible to obtain additional benefit above simple peripheral depletion of B cells. As such there are a number of inhibitors of B cell function and B cell depleting agents that have been developed for myeloma and B cell leukaemia and lymphoma, which could potentially be used off-label or as an experimental treatment for advanced (progressive) MS.

Cladribine: mechanisms and mysteries in multiple sclerosis

OBJECTIVES

The aims of this manuscript were to review the evidence for the efficacy and safety of cladribine in multiple sclerosis (MS) and to review the molecular and cellular mechanisms by which cladribine acts as a disease-modifying therapy in MS.

METHODS

This is a narrative review of the available clinical and preclinical data on the use of cladribine in MS.

RESULTS

Clinical trial data argue strongly that cladribine is a safe and effective therapy for relapsing MS and that it may also be beneficial in progressive MS. The pharmacology of cladribine explains how it is selectively toxic towards lymphocytes. Immunophenotyping studies show that cladribine depletes lymphocyte populations in vivo with a predilection for B cells. In vitro studies demonstrate that cladribine also exerts immunomodulatory influences over innate and adaptive immunity.

CONCLUSIONS

Cladribine is a safe and effective form of induction therapy for relapsing MS. Its mechanism of benefit is not fully understood but the most striking action is selective, long-lasting, depletion of B lymphocytes with a particular predilection for memory B cells. The in vivo relevance of its other immunomodulatory actions is unknown. The hypothesis that cladribine's action of benefit is to deplete memory B cells is important: if correct, it implies that selective targeting of this cell population and sparing of other lymphocytes could modify disease activity without predisposing to immunosuppression-related complications.

Cladribine induces long lasting oligoclonal bands disappearance in relapsing multiple sclerosis patients: 10-year observational study

BACKGROUND

There has been long-term interest in cladribine as a drug for the treatment of MS. The current study focused on the effect of cladribine on oligoclonal bands (OCB) expression in the CSF in relapsing-remitting MS (RRMS) patients observed over 10 years.

METHODS

29 treatment-naive subjects with RRMS were prospectively enrolled and received induction therapy with subcutaneous parenteral cladribine (at a cumulative dose of 1.8 mg/kg; divided into 6 courses every 5 weeks given for 4-6 days, depending on patients' body weight). Selected patients received maintenance doses in the follow-up period.

RESULTS

Isoelectric focusing revealed that 55% of patients did not have OCB in CSF after cladribine treatment as compared to baseline testing when 100% of patients were positive for OCB. There were no significant differences in Expanded Disability Status Scale scores at baseline and at the end of treatment cycle between OCB-positive vs. OCB-negative subgroups. At the last follow-up, OCB-negative patients had lower disability compared to OCB-positive patients (p = 0.03).

CONCLUSION

Cladribine-induced immune reconstitution leads to long lasting suppression of intrathecal humoral response, which might be an additional mechanism that enhances the therapeutic effect on disease progression in RRMS patients.

Disease activity in progressive multiple sclerosis can be effectively reduced by cladribine

BACKGROUND

Evidence suggests people with non-relapsing deteriorating ("progressive") multiple sclerosis (pwPMS) may benefit from disease-modifying immune therapy (DMT). However, only one such treatment (ocrelizumab) has been licensed and is highly restricted to pwPMS suffering from the primary progressive phenotype. The difficulties assessing treatment outcome in pwPMS is one important reason for the lack of respective DMT. The concentration of neurofilaments in the cerebrospinal fluid (CSF) provides a biomarker of neuro-axonal damage, and both neurofilament light (NfL) and heavy chain (NfH) levels have been used as outcome indices and to guide treatment choices.

METHODS

We report on two pwPMS, who were treated with subcutaneous cladribine undergoing CSF NfL testing, alongside MRI and clinical follow-up, before and after treatment.

RESULTS

Cladribine treatment was well tolerated without any side effects. CSF NfL after treatment revealed significant reduction (by 73% and 80%, respectively) corroborating the MRI detectable drop in disease activity. Disability mildly progressed in one, and remained stable in the other pwPMS.

CONCLUSIONS

pwPMS with detectable disease activity (MRI, elevated NfL) should be considered for DMT. NfL appears to be a sensitive index of treatment effect in pwPMS, and may be a useful outcome in clinical trials targeting this patient group. Over and above its licensed indication (relapsing MS), cladribine may be an effective treatment option for pwPMS.

Cladribine tablets' potential role as a key example of selective immune reconstitution therapy in multiple sclerosis

Multiple sclerosis (MS) is one of the most important, disabling, and prevalent neurological disorders of young adults. It is a chronic inflammatory and neurodegenerative disease when autoreactive B and T cells have downstream effects that result in demyelination and neuronal loss. Anti-inflammatory disease-modifying therapies do have proven efficacy in delaying disease and disability progression in MS. While the progress in MS treatments has already improved the prognosis and quality of patients’ lives overall, there are some clear shortcomings and unmet needs in the current MS treatment landscape. The most promising means of MS treatment is selective immune reconstitution therapy (SIRT). This therapy is given in short-duration courses of immunosuppression, producing durable effects on the immune system and preventing nervous tissue loss. This review discusses the mechanisms of action and the data of clinical trials of cladribine tablets as an example of SIRT in MS. The clinical benefits of cladribine tablets in these studies include decreased relapse rate and disability progression with large reductions in lesion activity, and protection against brain volume loss. Whether all of these neurological findings are direct results of lymphocyte depletion, or if there are downstream effects on other, unknown, neurodegenerative processes are yet to be determined, but these clearly point to an interesting area of research.

Cladribine treatment of multiple sclerosis is associated with depletion of memory B cells

Background

The mechanism of action of oral cladribine, recently licensed for relapsing multiple sclerosis, is unknown.

Objective

To determine whether cladribine depletes memory B cells consistent with our recent hypothesis that effective, disease-modifying treatments act by physical/functional depletion of memory B cells.

Methods

A cross-sectional study examined 40 people with multiple sclerosis at the end of the first cycle of alemtuzumab or injectable cladribine. The relative proportions and absolute numbers of peripheral blood B lymphocyte subsets were measured using flow cytometry. Cell-subtype expression of genes involved in cladribine metabolism was examined from data in public repositories.

Results

Cladribine markedly depleted class-switched and unswitched memory B cells to levels comparable with alemtuzumab, but without the associated initial lymphopenia. CD3⁺ T cell depletion was modest. The mRNA expression of metabolism genes varied between lymphocyte subsets. A high ratio of deoxycytidine kinase to group I cytosolic 5′ nucleotidase expression was present in B cells and was particularly high in mature, memory and notably germinal centre B cells, but not plasma cells.

Conclusions

Selective B cell cytotoxicity coupled with slow repopulation kinetics results in long-term, memory B cell depletion by cladribine. These may offer a new target, possibly with potential biomarker activity, for future drug development.

Electronic supplementary material

The online version of this article (10.1007/s00415-018-8830-y) contains supplementary material, which is available to authorized users.

Cladribine to Treat Relapsing Forms of Multiple Sclerosis

Cladribine is a purine nucleoside analogue that selectively depletes peripheral lymphocytes without a major impact on cells of the innate immune system. An oral formulation of cladribine has been developed to be given as short courses over two annual cycles. Oral cladribine results in the peripheral depletion of lymphocytes that is gradual, occurring over several weeks, and is not associated with a cell lysis syndrome, has a greater impact on B cells than T cells, and is followed by gradual reconstitution of the peripheral lymphocyte counts over several months. Oral cladribine is effective in relapsing forms of multiple sclerosis. As a selective immune reconstitution therapy (SIRT), cladribine acts as a short-term immunosuppressant, relative to other maintenance immunosuppressive therapies that result in long-term immunosuppression. The main safety signal that has emerge relates primarily to herpes zoster infection, which was more common in patients with higher grades of lymphopenia, in particular grade 3 and 4 lymphopenia. Data from the oral cladribine extension trial and safety register, and reanalysis of the pivotal phase III trial has indicated that oral cladribine is unlikely to be associated with an increased short- to intermediate-term risk of malignancy.

Safety and efficacy of cladribine tablets in patients with relapsing-remitting multiple sclerosis: Results from the randomized extension trial of the CLARITY study

BACKGROUND

In the 2-year CLARITY study, cladribine tablets significantly improved clinical and magnetic resonance imaging (MRI) outcomes (vs placebo) in patients with relapsing-remitting multiple sclerosis (MS).

OBJECTIVE

To assess the safety and efficacy of cladribine treatment in a 2-year Extension study.

METHODS

In this 2-year Extension study, placebo recipients from CLARITY received cladribine 3.5 mg/kg; cladribine recipients were re-randomized 2:1 to cladribine 3.5 mg/kg or placebo, with blind maintained.

RESULTS

A total of 806 patients were assigned to treatment. Adverse event rates were generally similar between groups, but lymphopenia Grade ⩾ 3 rates were higher with cladribine than placebo (Grade 4 lymphopenia occurred infrequently). In patients receiving cladribine 3.5 mg/kg in CLARITY and experiencing lymphopenia Grade ⩾ 3 in the Extension, >90% of those treated with cladribine 3.5 mg/kg and all treated with placebo in the Extension, recovered to Grade 0-1 by study end. Cladribine treatment in CLARITY produced efficacy improvements that were maintained in patients treated with placebo in the Extension; in patients treated with cladribine 3.5 mg/kg in CLARITY, approximately 75% remained relapse-free when given placebo during the Extension.

CONCLUSION

Cladribine tablets treatment for 2 years followed by 2 years' placebo treatment produced durable clinical benefits similar to 4 years of cladribine treatment with a low risk of severe lymphopenia or clinical worsening. No clinical improvement in efficacy was apparent following further treatment with cladribine tablets after the initial 2-year treatment period in this trial setting.

Positive impact of cladribine on quality of life in people with relapsing multiple sclerosis

Background:

A number of elements of the pivotal ‘cladribine tablets treating multiple sclerosis orally’ (CLARITY) trial have remained unpublished.

Objective:

To report the impact of cladribine on health-related quality of life (QoL) in people with relapsing multiple sclerosis (pwRMS).

Methods:

QoL data from the phase III trial of two different doses (3.5 and 5.25 mg/kg) of oral cladribine in pwRMS were acquired from the European Medicines Agency through Freedom of Information. Spearman’s rank correlation was used to analyse the relationship between baseline QoL scores and baseline Expanded Disability Status Scale (EDSS) scores. Responses of the Euro Quality of Life 5 Dimensions (EQ-5D) and Multiple Sclerosis Quality of Life-54 (MSQOL-54) questionnaires were compared between treatment and control groups using univariate analyses of covariance.

Results:

In total, n = 5148 EQ-5D responses and n = 894 MSQOL-54 physical, mental health and dimension scores were extracted. Baseline EQ-5D indices correlated with EDSS scores. After 2 years, pwRMS taking 3.5 (p = .001) and 5.25 mg/kg (p = .022) reported significantly improved EQ-5D index scores compared with placebo. Positive, yet non-significant, differences were detected in MSQOL-54 scores between cladribine and placebo.

Conclusion:

Analysis of the CLARITY dataset suggests that, over and above its established clinical efficacy, cladribine leads to improved QoL over 96 weeks. ClinicalTrials.gov identifier: NCT00213135.

Cladribine to treat disease exacerbation after fingolimod discontinuation in progressive multiple sclerosis

Rebound disease following cessation of disease modifying treatment (DMT) has been reported in people with both relapsing and progressive multiple sclerosis (pwRMS, pwPMS) questioning strict separation between these two phenotypes. While licensed DMT is available for pwRMS to counter rebound disease, no such option exists for pwPMS. We report on a pwPMS who developed rebound disease, with 45 Gadolinium-enhancing lesions on T1 weighted MRI brain, within 6 months after fingolimod 0.5 mg/day was stopped. Treatment with a short course of subcutaneous cladribine 60 mg led to effective suppression of inflammatory activity and partial recovery with no short-term safety issues or adverse events.

Pharmacological Approaches to the Management of Secondary Progressive Multiple Sclerosis

It is well recognised that the majority of the impact of multiple sclerosis (MS), both personal and societal, arises in the progressive phase where disability accumulates inexorably. As such, progressive MS (PMS) has been the target of pharmacological therapies for many years. However, there are no current licensed treatments for PMS. This stands in marked contrast to relapsing remitting MS (RRMS) where trials have resulted in numerous licensed therapies. PMS has proven to be a more difficult challenge compared to RRMS and this review focuses on secondary progressive MS (SPMS), where relapses occur before the onset of gradual, irreversible disability, and not primary progressive MS where disability accumulation occurs without prior relapses. Although there are similarities between the two forms, in both cases pinpointing when PMS starts is difficult in a condition in which disability can vary from day to day. There is also an overlap between the pathology of relapsing and progressive MS and this has contributed to the lack of well-defined outcomes, both surrogates and clinically relevant outcomes in PMS. In this review, we used the search term 'randomised controlled clinical drug trials in secondary progressive MS' in publications since 1988 together with recently completed trials where results were available. We found 34 trials involving 21 different molecules, of which 38% were successful in reaching their primary outcome. In general, the trials were well designed (e.g. double blind) with sample sizes ranging from 35 to 1949 subjects. The majority were parallel group, but there were also multi-arm and multidose trials as well as the more recent use of adaptive designs. The disability outcome most commonly used was the Expanded Disability Status Scale (EDSS) in all phases, but also magnetic resonance imaging (MRI)-measured brain atrophy has been utilised as a surrogate endpoint in phase II studies. The majority of the treatments tested in SPMS over the years were initially successful in RRMS. This has a number of implications in terms of targeting SPMS, but principally implies that the optimal strategy to target SPMS is to utilise the prodrome of relapses to initiate a therapy that will aim to both prevent progression and slow its accumulation. This approach is in agreement with the early targeting of MS but requires treatments that are both effective and safe if it is to be used before disability is a major problem. Recent successes will hopefully result in the first licensed therapy for PMS and enable us to test this approach.

Both cladribine and alemtuzumab may effect MS via B-cell depletion

Objective:

To understand the efficacy of cladribine (CLAD) treatment in MS through analysis of lymphocyte subsets collected, but not reported, in the pivotal phase III trials of cladribine and alemtuzumab induction therapies.

Methods:

The regulatory submissions of the CLAD Tablets Treating Multiple Sclerosis Orally (CLARITY) (NCT00213135) cladribine and Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis, study one (CARE-MS I) (NCT00530348) alemtuzumab trials were obtained from the European Medicine Agency through Freedom of Information requests. Data were extracted and statistically analyzed.

Results:

Either dose of cladribine (3.5 mg/kg; 5.25 mg/kg) tested in CLARITY reduced the annualized relapse rate to 0.16–0.18 over 96 weeks, and both doses were similarly effective in reducing the risk of MRI lesions and disability. Surprisingly, however, T-cell depletion was rather modest. Cladribine 3.5 mg/kg depleted CD4⁺ cells by 40%–45% and CD8⁺ cells by 15%–30%, whereas alemtuzumab suppressed CD4⁺ cells by 70%–95% and CD8⁺ cells by 47%–55%. However, either dose of cladribine induced 70%–90% CD19⁺ B-cell depletion, similar to alemtuzumab (90%). CD19⁺ cells slowly repopulated to 15%–25% of baseline before cladribine redosing. However, alemtuzumab induced hyperrepopulation of CD19⁺ B cells 6–12 months after infusion, which probably forms the substrate for B-cell autoimmunities associated with alemtuzumab.

Conclusions:

Cladribine induced only modest depletion of T cells, which may not be consistent with a marked influence on MS, based on previous CD4⁺ T-cell depletion studies. The therapeutic drug-response relationship with cladribine is more consistent with lasting B-cell depletion and, coupled with the success seen with monoclonal CD20⁺ depletion, suggests that B-cell suppression could be the major direct mechanism of action.

Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function that results from immune-mediated inflammation, demyelination, and subsequent axonal damage.

Clinically, most MS patients experience recurrent episodes (relapses) of neurological impairment, but in most cases (60–80%) the course of the disease eventually becomes chronic and progressive, leading to cumulative motor, sensory, and visual disability, and cognitive deficits.

The course of the disease is largely unpredictable and its clinical presentation is variable, but its predilection for certain parts of the CNS, which includes the optic nerves, the brain stem, cerebellum, and cervical spinal cord, provides a characteristic constellation of signs and symptoms. Several variants of MS have been nowadays defined with variable immunopathogenesis, course and prognosis. Many new treatments targeting the immune system have shown efficacy in preventing the relapses of MS and have been introduced to its management during the last decade.

Metabolism, Biochemical Actions, and Chemical Synthesis of Anticancer Nucleosides, Nucleotides, and Base Analogs

Nucleoside, nucleotide, and base analogs have been in the clinic for decades to treat both viral pathogens and neoplasms. More than 20% of patients on anticancer chemotherapy have been treated with one or more of these analogs. This review focuses on the chemical synthesis and biology of anticancer nucleoside, nucleotide, and base analogs that are FDA-approved and in clinical development since 2000. We highlight the cellular biology and clinical biology of analogs, drug resistance mechanisms, and compound specificity towards different cancer types. Furthermore, we explore analog syntheses as well as improved and scale-up syntheses. We conclude with a discussion on what might lie ahead for medicinal chemists, biologists, and physicians as they try to improve analog efficacy through prodrug strategies and drug combinations.

Primary progressive multiple sclerosis: current therapeutic strategies and future perspectives

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory condition of the central nervous system with heterogeneous features. Primary progressive (PP) MS is a rare disease subtype characterized by continuous disability worsening from onset. No disease-modifying therapy is currently approved for PP MS due to the negative or inconsistent results of clinical trials conducted on a wide range of interventions, which are reviewed in the present paper. Areas covered: The features and results of randomized trials of disease-modifying treatments for PP MS are discussed, including immunosuppressants, immunomodulators, monoclonal antibodies, and putative neuroprotective agents. Expert commentary: The recent encouraging results of the ocrelizumab trial in PP MS, the first to reach the primary disability endpoint, indicate B cells as a promising therapeutic target to prevent disease progression. Other emerging treatment strategies include cell metabolism modulation and inflammatory pathways inhibition, which are being investigated in several ongoing phase II and III placebo-controlled trials. Future PP MS trials will need to systematically include efficacy endpoints other than physical disability alone, such as cognition, quality of life, advanced MRI measures and molecular biomarkers.

Pharmacological Approaches to Delaying Disability Progression in Patients with Multiple Sclerosis

In individuals with multiple sclerosis, physical and cognitive disability progression are clinical and pathophysiological hallmarks of the disease. Despite shortcomings, particularly in capturing cognitive deficits, the Expanded Disability Status Scale is the assessment of disability progression most widely used in clinical trials. Here, we review treatment effects on disability that have been reported in large clinical trials of disease-modifying treatment, both among patients with relapsing-remitting disease and among those with progressive disease. However, direct comparisons are confounded to some degree by the lack of consistency in assessment of disability progression across trials. Confirmed disability progression (CDP) is a more robust measure when performed over a 6-month than a 3-month interval, and reduction in the risk of 6-month CDP in phase III trials provides good evidence for the beneficial effects on disability of several high-efficacy treatments for relapsing-remitting disease. It is also becoming increasingly clear that therapies effective in relapsing-remitting disease have little impact on the course of progressive disease. Given that the pathophysiological mechanisms, which lead to the long-term accrual of physical and cognitive deficits, are evident at the earliest stages of disease, it remains a matter of debate whether the most effective therapies are administered early enough to afford patients the best long-term outcomes.

Evaluation of Study and Patient Characteristics of Clinical Studies in Primary Progressive Multiple Sclerosis: A Systematic Review

Background

So far, clinical studies in primary progressive MS (PPMS) have failed to meet their primary efficacy endpoints. To some extent this might be attributable to the choice of assessments or to the selection of the study population.

Objective

The aim of this study was to identify outcome influencing factors by analyzing the design and methods of previous randomized studies in PPMS patients without restriction to intervention or comparator.

Methods

A systematic literature search was conducted in MEDLINE, EMBASE, BIOSIS and the COCHRANE Central Register of Controlled Trials (inception to February 2015). Keywords included PPMS, primary progressive multiple sclerosis and chronic progressive multiple sclerosis. Randomized, controlled trials of at least one year’s duration were selected if they included only patients with PPMS or if they reported sufficient PPMS subgroup data. No restrictions with respect to intervention or comparator were applied. Study quality was assessed by a biometrics expert. Relevant baseline characteristics and outcomes were extracted and compared.

Results

Of 52 PPMS studies identified, four were selected. Inclusion criteria were notably different among studies with respect to both the definition of PPMS and the requirements for the presence of disability progression at enrolment. Differences between the study populations included the baseline lesion load, pretreatment status and disease duration. The rate of disease progression may also be an important factor, as all but one of the studies included a large proportion of patients with a low progression rate. In addition, the endpoints specified could not detect progression adequately.

Conclusion

Optimal PPMS study methods involve appropriate patient selection, especially regarding the PPMS phenotype and progression rate. Functional composite endpoints might be more sensitive than single endpoints in capturing progression.

Oral disease-modifying therapies for multiple sclerosis

Classical multiple sclerosis (MS) treatments using first-line injectable drugs, although widely applied, remain a major concern in terms of therapeutic adherence and efficacy. New oral drugs recently approved for MS treatment represent significant advances in therapy. The oral route of administration clearly promotes patient satisfaction and increases therapeutic compliance. However, these drugs may also have safety and tolerability issues, and a thorough analysis of the risks and benefits is required. Three oral drugs have been approved by regulatory agencies for MS treatment: fingolimod, teriflunomide, and dimethyl fumarate. This article reviews the mechanisms of action, safety, and efficacy of these drugs and two other drugs that have yielded positive results in phase III trials: cladribine and laquinimod.

Immunotherapy of multiple sclerosis: the state of the art

It is widely accepted that the main common pathogenetic pathway in multiple sclerosis (MS) involves an immune-mediated cascade initiated in the peripheral immune system and targeting CNS myelin. Logically, therefore, the therapeutic approaches to the disease include modalities aiming at downregulation of the various immune elements that are involved in this immunologic cascade. Since the introduction of interferons in 1993, which were the first registered treatments for MS, huge steps have been made in the field of MS immunotherapy. More efficious and specific immunoactive drugs have been introduced and it appears that the increased specificity for MS of these new treatments is paralleled by greater efficacy. Unfortunately, this seemingly increased efficacy has been accompanied by more safety issues. The immunotherapeutic modalities can be divided into two main groups: those affecting the acute stages (relapses) of the disease and the long-term treatments that are aimed at preventing the appearance of relapses and the progression in disability. Immunomodulating treatments may also be classified according to the level of the 'immune axis' where they exert their main effect. Since, in MS, a neurodegenerative process runs in parallel and as a consequence of inflammation, early immune intervention is warranted to prevent progression of relapses of MS and the accumulation of disability. The use of neuroimaging (MRI) techniques that allow the detection of silent inflammatory activity of MS and neurodegeneration has provided an important tool for the substantiation of the clinical efficacy of treatments and the early diagnosis of MS. This review summarizes in detail the existing information on all the available immunotherapies for MS, old and new, classifies them according to their immunologic mechanisms of action and proposes a structured algorithm/therapeutic scheme for the management of the disease.

Impact of cladribine therapy on changes in circulating dendritic cell subsets, T cells and B cells in patients with multiple sclerosis

BACKGROUND

Cladribine causes sustained reduction in peripheral T and B cell populations while sparing other immune cells. We determined two populations of dendritic cells (DCs): namely CD1c(+)/CD19(-) (myeloid DCs) and CD303(+)/CD123(+) (plasmacytoid DCs), CD19(+) B lymphocytes, CD3(+) T lymphocytes and CD4(+) or CD8(+) subpopulations in patients with multiple sclerosis after cladribine therapy.

METHODS

We examined 50 patients with secondary progressive multiple sclerosis (SP MS) according to McDonalds et al.'s criteria, 2001 [15]. Blood samples were collected before the initiation of cladribine therapy and after 1st, 2nd, 3th, 4th and 5th courses of treatment. DC subsets, T and B cells were analyzed by flow cytometry.

RESULTS

During cladribine treatment the myeloid DCs CD1c(+)/CD19(-) did not change (p=0.73175), and the plasmacytoid DCs CD303(+)/CD123(+) significantly increased (p=0.00034) which resulted in significant changes in the ratio of myeloid DCs to plasmacytoid DCs (p=0.00273). During therapy, B lymphocyte CD19(+) significantly decreased (p=0.00005) and significant changes in CD4(+) cells (p=0.00191), changes in CD8(+) cells (p=0.05760) and significant changes in CD3(+) (p=0.01822) were found.

CONCLUSIONS

We noticed significant trend to increase the CD303(+) circulating the dendritic cells. This population produces large amounts of IFN-alfa. We found significant and rapid decrease in B cells and CD4(+) Th cells. Our results suggest two possible ways of beneficial cladribine influence on immune system in MS. Induction of IFN-alfa producing cells and their predominance over BDCA-1(+) DCs, which are associated with cytotoxic response. Additionally, cladribine could influence two populations of lymphocytes: B cells and Th lymphocytes responsible for induction of immune response against myelin antigens.

Management of secondary progressive multiple sclerosis: prophylactic treatment-past, present, and future aspects

OPINION STATEMENT

Whereas the number of treatment options in relapsing-remitting multiple sclerosis (RRMS) is growing constantly, alternatives are rare in the case of secondary-progressive multiple sclerosis (SPMS). Besides mitoxantrone in North America and Europe, interferon beta-1b and beta-1a are approved for treatment in Europe. Glucocorticosteroids, azathioprine, intravenous immunoglobulins (IVIG) and cyclophosphamide (CYC), although not approved, are commonly utilized in SPMS. Currently monoclonal antibodies (mab), and masitinib are under examination for treatment for SPMS. Hematopoietic stem cell transplantation and immunoablative stem cell transplantation are therapies with the aim of reconstitution of the immune system. This review gives information on the different therapeutics and the trials that tested them. Pathophysiological considerations are presented in view of efficacy of the therapeutics. In addition, therapeutics that showed no efficacy in trials or with unacceptable side effects are topics of this review.

Oral available agents in the treatment of relapsing remitting multiple sclerosis: an overview of merits and culprits

Multiple sclerosis (MS) is a chronic immunological disease of the central nervous system characterized by early inflammatory demyelination and subsequent neurodegeneration. Major therapeutic progress has occurred during the past decade, in particular since the introduction of immunomodulatory agents, however, MS is still an incurable disease. In addition, parenteral application of the currently licensed drugs is associated with injection-related adverse events (AEs) and low patient compliance. Thus, there remains an unmet need for the development of more effective and well tolerated oral therapies for the treatment of MS. A number of new orally administered agents including fingolimod, laquinimod, teriflunomide, cladribine, and BG-12 have been licensed recently or are currently under investigation in relapsing remitting MS patients. In multi-center, randomized, placebo-controlled phase III clinical studies, all of these agents have already shown their efficacy on both clinical disease parameters and magnetic resonance imaging-based measures of disease activity in patients with relapsing remitting MS. However, there are essential differences concerning their clinical efficacy and side-effect profiles. Additionally, the mechanisms by which these substances exert clinical efficacy have not been fully elucidated. In this article, we review the pharmaceutical properties of fingolimod, laquinimod, teriflunomide, cladribine, and BG-12; and their suggested mechanisms of action, clinical efficacy, and side-effect profiles.

Current and emerging multiple sclerosis therapeutics

For a disease whose cause remains elusive, there has been a paradoxical growth in multiple sclerosis (MS) therapeutics. During the past 17 years, six therapeutic drugs for MS were brought to market. All of these disease-modifying therapies (DMTs) have shown a beneficial effect in reducing the number of exacerbations in double-blind placebo-controlled trials, and three drugs (subcutaneous [SC]/IM interferon beta-1a, natalizumab) have been shown to reduce relapses, decrease MRI activity, and reduce the risk of sustained disability after 2 years of treatment. No controlled studies exist to show long-term benefit with any of the current DMTs. Immunosuppressive drug (ISD) therapies continue to play a role in the management of patients who fail to respond to immunomodulatory agents. These agents, however, have shown mixed data in terms of efficacy and put patients at higher risk for the development of secondary cancers. Plasma exchange for severe relapses not responsive to corticosteroid therapy has regained interest in the past few years. Furthermore, six new agents that will dramatically impact our ability to prevent disability in patients with MS are in late-stage or have completed phase 3 clinical development. Determining the risk-benefit calculations that we will need to employ toward these new drugs and the algorithms for switching therapies will be critical issues in the next 5 years. This article highlights the clinical efficacy of the current DMTs/ISDs and discusses the current treatment options for clinically isolated syndrome, relapsing-remitting MS (RRMS), and exacerbations of RRMS. It also addresses the management of a suboptimal response to the DMTs; discusses the challenge of primary progressive MS; and presents an overview of emerging therapeutic options.

Current and emerging therapies for the treatment of multiple sclerosis: focus on cladribine

Multiple Sclerosis (MS) is a chronic inflammatory, immune-mediated, demyelinating disorder of the central nervous system with a heterogeneous clinical presentation and pathology in which activated lymphocytes play an important role in mediating tissue damage. Until recently, all first line therapies for MS were injectable. Several oral medications have been studied for preventative treatment of MS. Cladribine (2-chlorodeoxyadenosine) is a purine nucleoside analog that has been used for the treatment of several hematologic neoplasms, with a unique lymphcytotoxic mechanism of action. Cladribine has been investigated as treatment of MS for more than 15 years. A recent placebo-controlled, double-blind study of cladribine, CLARITY, showed decreased relapse rates, risk of disability progression and MRI measures of disease activity at 96 weeks. Cladribine's strengths included high efficacy and convenient, biannual oral dosing. However, concerns about safety prevented the FDA from approving cladribine in 2011. Thus, use of cladribine for treatment of relapsing and remitting multiple sclerosis will remain off-label.