Antibodies to glatiramer acetate do not interfere with its biological functions and therapeutic efficacy

Antidrug Antibodies Against Biological Treatments for Multiple Sclerosis

The development of antidrug antibodies (ADAs) is a major problem in several recombinant protein therapies used in the treatment of multiple sclerosis (MS). The etiology of ADAs is multifaceted. The predisposition for a breakdown of immune tolerance is probably genetically determined, and many factors may contribute to the immunogenicity, including structural properties, formation of aggregates, and presence of contaminants and impurities from the industrial manufacturing process. ADAs may have a neutralizing capacity and can reduce or abrogate the bioactivity and therapeutic efficacy of the drug and cause safety issues. Interferon (IFN)-β was the first drug approved for the treatment of MS, and-although it is generally recognized that neutralizing antibodies (NAbs) appear and potentially have a negative effect on therapeutic efficacy-the use of routine measurements of NAbs and the interpretation of the presence of NAbs has been debated at length. NAbs appear after 9-18 months of therapy in up to 40% of patients treated with IFNβ, and the frequency and titers of NAbs depend on the IFNβ preparation. Although all pivotal clinical trials of approved IFNβ products in MS exhibited a detrimental effect of NAbs after prolonged therapy, some subsequent studies did not observe clinical effects from NAbs, which led to the claim that NAbs did not matter. However, it is now largely agreed that persistently high titers of NAbs indicate an abrogation of the biological response and, hence, an absence of therapeutic efficacy, and this observation should lead to a change of therapy. Low and medium titers are ambiguous, and treatment decisions should be guided by determination of in vivo messenger RNA myxovirus resistance protein A induction after IFNβ administration and clinical disease activity. During treatment with glatiramer acetate, ADAs occur frequently but do not appear to adversely affect treatment efficacy or result in adverse events. ADAs occur in approximately 5% of patients treated with natalizumab within 6 months of therapy, and persistent NAbs are associated with a lack of efficacy and acute infusion-related reactions and should instigate a change of therapy. When using the anti-CD20 monoclonal antibodies ocrelizumab and ofatumumab in the treatment of MS, it is not necessary to test for NAbs as these occur very infrequently. Alemtuzumab is immunogenic, but routine measurements of ADAs are not recommended as the antibodies in the pivotal 2-year trials at the population level did not influence lymphocyte depletion or repopulation, efficacy, or safety. However, in some individuals, NAbs led to poor lymphocyte depletion.

Randomized peptide assemblies for enhancing immune responses to nanomaterials

Biomaterials capable of inducing immune responses with minimal associated inflammation are of interest in applications ranging from tissue repair to vaccines. Here we report the design of self-assembling randomized polypeptide nanomaterials inspired by glatiramoids, an immunomodulatory class of linear random copolymers. We hypothesized that peptide self-assemblies bearing similar randomized polypeptides would similarly raise responses skewed toward Type 2 immunity and T_H2 T-cell responses, additionally strengthening responses to co-assembled peptide epitopes in the absence of adjuvant. We developed a method for synthesizing self-assembling peptides terminated with libraries of randomized polypeptides (termed KEYA) with good batch-to-batch reproducibility. These peptides formed regular nanofibers and raised strong antibody responses without adjuvants. KEYA modifications dramatically improved uptake of peptide nanofibers in vitro by antigen presenting cells, and served as strong B-cell and T-cell epitopes in vivo, enhancing immune responses against epitopes relevant to influenza and chronic inflammation while inducing a KEYA-specific Type 2/T_H2/IL-4 phenotype. KEYA modifications also increased IL-4 production by T cells, extended the residence time of nanofibers, induced no measurable swelling in footpad injections, and decreased overall T cell expansion compared to unmodified nanofibers, further suggesting a T_H2 T-cell response with minimal inflammation. Collectively, this work introduces a biomaterial capable of raising strong Type 2/T_H2/IL-4 immune responses, with potential applications ranging from vaccination to tissue repair.

The Evolving Mechanisms of Action of Glatiramer Acetate

Glatiramer acetate (GA) is a synthetic amino acid copolymer that is approved for treatment of relapsing remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS). GA reduces multiple sclerosis (MS) disease activity and has shown comparable efficacy with high-dose interferon-β. The mechanism of action (MOA) of GA has long been an enigma. Originally, it was recognized that GA treatment promoted expansion of GA-reactive T-helper 2 and regulatory T cells, and induced the release of neurotrophic factors. However, GA treatment influences both innate and adaptive immune compartments, and it is now recognized that antigen-presenting cells (APCs) are the initial cellular targets for GA. The anti-inflammatory (M2) APCs induced following treatment with GA are responsible for the induction of anti-inflammatory T cells that contribute to its therapeutic benefit. Here, we review studies that have shaped our current understanding of the MOA of GA.

Demonstration of Biological and Immunological Equivalence of a Generic Glatiramer Acetate

BACKGROUND

In April 2015, the US Food and Drug Administration approved the first generic glatiramer acetate, Glatopa® (M356), as fully substitutable for Copaxone® 20 mg/mL for relapsing forms of multiple sclerosis (MS). This approval was accomplished through an Abbreviated New Drug Application that demonstrated equivalence to Copaxone.

METHOD

This article will provide an overview of the methods used to establish the biological and immunological equivalence of the two glatiramer acetate products, including methods evaluating antigenpresenting cell (APC) biology, T-cell biology, and other immunomodulatory effects.

RESULTS

In vitro and in vivo experiments from multiple redundant orthogonal assays within four biological processes (aggregate biology, APC biology, T-cell biology, and B-cell biology) modulated by glatiramer acetate in MS established the biological and immunological equivalence of Glatopa and Copaxone and are described. The following were observed when comparing Glatopa and Copaxone in these experiments: equivalent delays in symptom onset and reductions in "disease" intensity in experimental autoimmune encephalomyelitis; equivalent dose-dependent increases in Glatopa- and Copaxone- induced monokine-induced interferon-gamma release from THP-1 cells; a shift to a T helper 2 phenotype resulting in the secretion of interleukin (IL)-4 and downregulation of IL-17 release; no differences in immunogenicity and the presence of equivalent "immunofingerprints" between both versions of glatiramer acetate; and no stimulation of histamine release with either glatiramer acetate in basophilic leukemia 2H3 cell lines.

CONCLUSION

In summary, this comprehensive approach across different biological and immunological pathways modulated by glatiramer acetate consistently supported the biological and immunological equivalence of Glatopa and Copaxone.

Transferon™, a peptide mixture with immunomodulatory properties is not immunogenic when administered with various adjuvants

Transferon, a human dialyzable leukocyte extract (hDLE), is a biotherapeutic that comprises a complex mixture of low-molecular-weight peptides (< 10 kDa) and is used to treat diseases with an inflammatory component. Some biotherapeutics, including those composed of peptides, can induce anti-drug antibodies (ADA) that block or diminish their therapeutic effect. Nevertheless, few studies have evaluated peptide-derived drug immunogenicity. In this study, the immunogenicity of Transferon was examined in a murine model during an immunization scheme using the following adjuvants: Al(OH)₃, incomplete Freund's adjuvant (IFA), or Titermax Gold. The inoculation scheme entailed three routes of administration (intraperitoneal, Day 1; subcutaneous, Day 7; and intramuscular, Day 14) using 200 μg Transferon/inoculation. Serum samples were collected on Day 21. Total IgG levels were quantitated by affinity chromatography, and specific antibodies against components of Transferon were analyzed by dot-blot and ELISA. Ovalbumin (OVA, 44 kDa) and peptides from hydrolyzed collagen (PFHC, < 17 kDa) were used as positive and negative controls, respectively, in the same inoculation scheme and analyses for Transferon. OVA, PFHC, and Transferon increased total IgG concentrations in mice. However, only IgG antibodies against OVA were detected. Based on the results, it is concluded that Transferon does not induce generation of specific antibodies against its components in this model, regardless of adjuvant and route of administration. These results support the safety of Transferon by confirming its inability to induce ADA in this animal model.

Impact of Glatiramer Acetate on B Cell-Mediated Pathogenesis of Multiple Sclerosis

Growing evidence indicates that B cells play a key role in the pathogenesis of multiple sclerosis (MS). B cells occupy distinct central nervous system (CNS) compartments in MS, including the cerebrospinal fluid and white matter lesions. Also, it is now known that, in addition to entering the CNS, B cells can circulate into the periphery via a functional lymphatic system. Data suggest that the role of B cells in MS mainly involves their in situ activation in demyelinating lesions, leading to altered pro- and anti-inflammatory cytokine secretion, and a highly effective antigen-presenting cell function, resulting in activation of memory or naïve T cells. Clinically, B cell-depleting agents show significant efficacy in MS. In addition, many disease-modifying therapies (DMTs) traditionally understood to target T cells are now known to influence B cell number and function. One of the earliest DMTs to be developed, glatiramer acetate (GA), has been shown to reduce the total frequency of B cells, plasmablasts, and memory B cells. It also appears to promote a shift toward reduced inflammation by increasing anti-inflammatory cytokine release and/or reducing pro-inflammatory cytokine release by B cells. In the authors' opinion, this may be mediated by cross-reactivity of B cell receptors for GA with antigen (possibly myelin basic protein) expressed in the MS lesion. More research is required to further characterize the role of B cells and their bidirectional trafficking in the pathogenesis of MS. This may uncover novel targets for MS treatments and facilitate the development of B cell biomarkers of drug response.

Process signatures in glatiramer acetate synthesis: structural and functional relationships

Glatiramer Acetate (GA) is an immunomodulatory medicine approved for the treatment of multiple sclerosis, whose mechanisms of action are yet to be fully elucidated. GA is comprised of a complex mixture of polypeptides with different amino acid sequences and structures. The lack of sensible information about physicochemical characteristics of GA has contributed to its comprehensiveness complexity. Consequently, an unambiguous determination of distinctive attributes that define GA is of highest relevance towards dissecting its identity. Herein we conducted a study of characteristic GA heterogeneities throughout its manufacturing process (process signatures), revealing a strong impact of critical process parameters (CPPs) on the reactivity of amino acid precursors; reaction initiation and polymerization velocities; and peptide solubility, susceptibility to hydrolysis, and size-exclusion properties. Further, distinctive GA heterogeneities were correlated to defined immunological and toxicological profiles, revealing that GA possesses a unique repertoire of active constituents (epitopes) responsible of its immunological responses, whose modification lead to altered profiles. This novel approach established CPPs influence on intact GA peptide mixture, whose physicochemical identity cannot longer rely on reduced properties (based on complete or partial GA degradation), providing advanced knowledge on GA structural and functional relationships to ensure a consistent manufacturing of safe and effective products.

Clinical significance of glatiramer acetate antibodies

Glatiramer acetate is a mixture of synthetic peptides that are cross-reactive with MBP. The antigen-based therapy induces a shift to an anti-inflammatory Th2 bias and is used in the treatment of relapsing-remitting multiple sclerosis. Like other peptide antigens, GA induces an antibody response in all patients. In contrast to biologically active agents, such as the recombinant interferon beta drugs, GA is a peptide antigen that lacks intrinsic biological activity. In vitro and in vivo data have shown that GA-reactive antibodies are not neutralizing. Antibodies do not alter the principal immunological effects of GA, including binding to MHC Class II molecules, activation and proliferation of GA-reactive T cells, and the release of anti-inflammatory Th2 cytokines. Higher antibody titres do not appear to be associated with a deterioration in clinical endpoints, such as relapse rate, EDSS progression or the occurrence of side effects in MS patients treated with GA. The presence of GA-reactive antibodies may promote remyelination and enhance the immunological and clinical effects of GA, indicating that they may be part of GA's mechanism of action. Multiple Sclerosis 2007; 13: S28—S35. http://msj.sagepub.com

Biomaterial strategies for generating therapeutic immune responses

Biomaterials employed to raise therapeutic immune responses have become a complex and active field. Historically, vaccines have been developed primarily to fight infectious diseases, but recent years have seen the development of immunologically active biomaterials towards an expanding list of non-infectious diseases and conditions including inflammation, autoimmunity, wounds, cancer, and others. This review structures its discussion of these approaches around a progression from single-target strategies to those that engage increasingly complex and multifactorial immune responses. First, the targeting of specific individual cytokines is discussed, both in terms of delivering the cytokines or blocking agents, and in terms of active immunotherapies that raise neutralizing immune responses against such single cytokine targets. Next, non-biological complex drugs such as randomized polyamino acid copolymers are discussed in terms of their ability to raise multiple different therapeutic immune responses, particularly in the context of autoimmunity. Last, biologically derived matrices and materials are discussed in terms of their ability to raise complex immune responses in the context of tissue repair. Collectively, these examples reflect the tremendous diversity of existing approaches and the breadth of opportunities that remain for generating therapeutic immune responses using biomaterials.

Once-daily glatiramer acetate decreases magnetic resonance imaging disease activity in Japanese patients with relapsing-remitting multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS) prevalence, clinical patterns, and treatment responses vary between races and geographical latitudes. Glatiramer acetate (GA; Copaxone) has provided a safe, effective treatment option for relapsing-remitting MS patients in the USA, European nations, and other countries for decades. The objective of the present study was to assess the safety and efficacy of GA in reducing magnetic resonance imaging disease activity in Japanese patients with active relapsing-remitting MS.

METHODS

This phase 2, multicenter, open-label, single-arm, 52-week study measured the effect of GA 20 mg once-daily on magnetic resonance imaging disease activity. GA efficacy was evaluated through week 36, and safety through week 52. The primary end-point was change in the mean number of T₁-weighted gadolinium-enhancing (GdE) lesions from pretreatment (weeks -8, -4 and baseline) to weeks 28, 32 and 36. Secondary end-points included a change in mean number of new T₂-weighted lesions, GdE lesion and T₂ lesion volumes, annualized relapse rate, and Expanded Disability Status Scale scores.

RESULTS

GA therapy reduced the number of new GdE lesions by 65.66% (95% CI 33.19-82.35%). The number of new T₂ lesions and GdE lesion volume were also reduced from pretreatment. The annualized relapse rate was reduced by 42% compared with the 1 year before treatment. Changes in T₂ lesion volume and Expanded Disability Status Scale scores were favorable, but less pronounced. Most common adverse events were injection-site reactions.

CONCLUSIONS

The present study confirmed the well-established safety, tolerability and efficacy profile of GA in Japanese MS patients.

[A place of first-line drugs in treatment of multiple sclerosis]

A rapidly changing set of drugs for treatment of multiple sclerosis (MS) leads to the necessity of searching for predictors of their efficacy. Understanding of pathogenetic processes in MS and mechanisms of action of different drugs play an important role in the search for markers of potential responders. The author analyses the presently accumulated information on the original drug copaxone (glatiramer acetate) including current concepts on the mechanism of action, long-term safety and efficacy. Data on the frequency and significance of adverse effects during treatment with glatiramer acetate as well as on the influence of the drug on pregnancy, postpartum course of MS and development of the infant who received glatiramer acetate prenatally compared to other disease-modifying drugs are presented.

The effect of glatiramer acetate therapy on functional properties of B cells from patients with relapsing-remitting multiple sclerosis

IMPORTANCE

This study describes what is, to our knowledge, the previously unknown effect of glatiramer acetate therapy on B cells in patients with relapsing-remitting multiple sclerosis (MS).

OBJECTIVE

To determine whether glatiramer acetate therapy normalizes dysregulated B-cell proliferation and cytokine production in patients with MS.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-two patients with MS who were receiving glatiramer acetate therapy and 22 treatment-naive patients with MS were recruited at The University of Texas Southwestern Medical Center MS clinic. Cell samples from healthy donors were obtained from HemaCare (Van Nuys, California) or Carter Blood Bank (Dallas, Texas). Treatment-naive patients with MS had not received any disease-modifying therapies for at least 3 months before the study.

EXPOSURES

Glatiramer acetate therapy for at least 3 months at the time of the study.

MAIN OUTCOMES AND MEASURES

B-cell phenotype and proliferation and immunoglobulin and cytokine secretion.

RESULTS

A restoration of interleukin 10 production by peripheral B cells was observed in patients undergoing glatiramer acetate therapy as well as a significant reduction of interleukin 6 production in a subset of patients who received therapy for less than 32 months. Furthermore, proliferation in response to high-dose CD40L was altered and immunoglobulin production was elevated in in vitro-activated B cells obtained from patients who received glatiramer acetate.

CONCLUSIONS AND RELEVANCE

Glatiramer acetate therapy remodels the composition of the B-cell compartment and influences cytokine secretion and immunoglobulin production. These data suggest that glatiramer acetate therapy affects several aspects of dysregulated B-cell function in MS that may contribute to the therapeutic mechanisms of glatiramer acetate.

Treatment Optimization in MS: Canadian MS Working Group Updated Recommendations

The Canadian Multiple Sclerosis Working Group (CMSWG) developed practical recommendations in 2004 to assist clinicians in optimizing the use of disease-modifying therapies (DMT) in patients with relapsing multiple sclerosis. The CMSWG convened to review how disease activity is assessed, propose a more current approach for assessing suboptimal response, and to suggest a scheme for switching or escalating treatment. Practical criteria for relapses, Expanded Disability Status Scale (EDSS) progression and MRI were developed to classify the clinical level of concern as Low, Medium and High. The group concluded that a change in treatment may be considered in any RRMS patient if there is a high level of concern in any one domain (relapses, progression or MRI), a medium level of concern in any two domains, or a low level of concern in all three domains. These recommendations for assessing treatment response should assist clinicians in making more rational choices in their management of relapsing MS patients.

Immunomodulation neuroprotection and remyelination - the fundamental therapeutic effects of glatiramer acetate: a critical review

Multiple sclerosis (MS) is a multifaceted heterogeneous disease with various patterns of tissue damage. In addition to inflammation and demyelination, widespread axonal and neuronal pathologies are central components of this disease. MS therapies aim to restrain the pathological processes, enhance protective mechanisms, and prevent disease progression. The amino acid copolymer, glatiramer acetate (GA, Copaxone), an approved treatment for MS, has a unique mode of action. Evidence from the animal model experimental autoimmune encephalomyelitis (EAE) and from MS patients indicates that GA affects various levels of the innate and the adaptive immune response, inducing deviation from the pro-inflammatory to the anti-inflammatory pathways. This includes competition for the binding of antigen presenting cells, driving dendritic cells, monocytes, and B-cells towards anti-inflammatory responses, induction of Th2/3 and T-regulatory cells, and downregulating of both Th1 and Th-17 cells. The immune cells induced by GA reach the inflamed disease organ and secrete in situ anti-inflammatory cytokines alleviating the pathological processes. Furthermore, cumulative findings have revealed that in addition to its immunomodulatory activities GA promotes neuroprotective repair processes such as neurotrophic factors secretion and remyelination. This review aims to provide a comprehensive overview on the diverse mechanism of action of GA in EAE/MS, in particular on the in situ effect of GA and its ability to generate neuroprotection and repair in the CNS. In view of its immunomodulatory activity, the beneficial effects of GA in various models of additional autoimmune related pathologies, such as immune rejection and inflammatory bowel disease (IBD), are also presented.

Glatiramer acetate in multiple sclerosis

Glatiramer acetate (Copaxone) is a disease-modifying agent approved by several health authorities worldwide for the treatment of relapsing-remitting multiple sclerosis. Although its primary target is the inflammatory component of the disease, there are emerging pieces of evidence suggesting that glatiramer acetate might also have a neuroprotective effect. In this review, the results of glatiramer acetate clinical trials and other relevant studies as well as the place of glatiramer acetate among other approved disease-modifying treatments for relapsing-remitting multiple sclerosis are discussed critically.

Multiple sclerosis disease-modifying therapies: adverse effect surveillance and management

There are five approved, partially effective, parenteral disease-modifying therapies for multiple sclerosis (MS), including three interferon-beta preparations, glatiramer acetate and the antineoplastic agent mitoxantrone. A sixth drug, natalizumab, was withdrawn from the market in 2005 but could return with increased safety measures. Careful surveillance for, and management of, the minor and serious adverse effects associated with these therapies in routine practice provides the best opportunity for maintaining compliance and achieving maximal therapeutic efficacy. This review outlines the strategies for the prevention, identification and management of the complications associated with administration and ongoing use of current MS therapies. These skills will become increasingly important to those caring for MS patients as contemporary treatment regimens become increasingly complex.

Two decades of subcutaneous glatiramer acetate injection: current role of the standard dose, and new high-dose low-frequency glatiramer acetate in relapsing-remitting multiple sclerosis treatment

Glatiramer acetate, a synthetic amino acid polymer analog of myelin basic protein, is one of the first approved drugs for the treatment of relapsing-remitting multiple sclerosis. Several clinical trials have shown consistent and sustained efficacy of glatiramer acetate 20 mg subcutaneously daily in reducing relapses and new demyelinating lesions on magnetic resonance imaging in patients with relapsing-remitting multiple sclerosis, as well as comparable efficacy to high-dose interferon beta. Some preclinical and clinical data suggest a neuroprotective role for glatiramer acetate in multiple sclerosis. Glatiramer acetate is associated with a relatively favorable side-effect profile, and importantly this was confirmed also during long-term use. Glatiramer acetate is the only multiple sclerosis treatment compound that has gained the US Food and Drug Administration pregnancy category B. All these data support its current use as a first-line treatment option for patients with clinical isolated syndrome or relapsing-remitting multiple sclerosis. More recent data have shown that high-dose glatiramer acetate (ie, 40 mg) given three times weekly is effective, safe, and well tolerated in the treatment of relapsing-remitting multiple sclerosis, prompting the approval of this dosage in the US in early 2014. This high-dose, lower-frequency glatiramer acetate might represent a new, more convenient regimen of administration, and this might enhance patients' adherence to the treatment, crucial for optimal disease control.

Glatiramer acetate: a review of its use in patients with relapsing-remitting multiple sclerosis and in delaying the onset of clinically definite multiple sclerosis

Glatiramer acetate (Copaxone(®)) is a synthetic analogue of the multiple sclerosis (MS)-associated antigen, myelin basic protein. Although its exact mechanisms of action in MS remain to be fully elucidated, the key mechanisms of action of glatiramer acetate appear to be modulation of the inflammatory response and neuroprotective and/or neuroregenerative effects. Subcutaneous glatiramer acetate is indicated for the treatment of adult patients with relapsing-remitting MS (RRMS) and the treatment of patients who have experienced a well-defined first clinical episode and have magnetic resonance imaging (MRI) features consistent with MS or have been determined to be at high risk of developing clinically definite MS (CDMS). In clinical trials in patients with RRMS, glatiramer acetate reduced the frequency of relapses and reduced the burden and activity of disease on MRI, was more effective than placebo and showed generally similar efficacy to subcutaneous interferon (IFN) β-1a and IFNβ-1b. Furthermore, the beneficial effects of glatiramer acetate were sustained during up to 15 years of treatment in an extension study. In patients with clinically isolated syndrome (CIS), glatiramer acetate significantly delayed the onset of CDMS compared with placebo. The drug was generally well tolerated in these patient populations, with injection-site reactions being the most commonly occurring adverse events. Therefore, glatiramer acetate remains a valuable first-line option in the treatment of RRMS and is an option for delaying the onset of CDMS in patients with CIS.

The pharmacokinetics of glatiramer acetate for multiple sclerosis treatment

INTRODUCTION

Multiple sclerosis (MS) is a T-cell-mediated disease affecting the central nervous system (CNS), characterized by demyelination and axonal degeneration. INF-β1b was the first drug approved for MS patients in 1993. In 1996, glatiramer acetate (GA), a synthetic copolymer, was approved in the USA for the treatment of relapsing-remitting MS (RRMS) and clinically isolated syndrome (CIS). Although the immunological action of GA has been fully investigated, the exact mechanisms of action of GA are still not completely elucidated. Several in vitro studies on mice and human antigen-presenting cells (APCs) have shown that GA is able to bind to the major histocompatibility complex (MHC), on the surface of APCs, recognizing myelin basic protein (MBP).

AREAS COVERED

This review explores the pharmacological characteristics of GA, its mechanism of action and its pharmacokinetics properties. The article also provides information on the efficacy, tolerability and an overview of the most important clinical data on GA.

EXPERT OPINION

Despite the development of novel compounds, it is not surprising that GA is, to date, one of the most prescribed drugs for RRMS patients and CIS patients. The proven efficacy and the mild adverse events, makes GA a good therapeutic option in the early stage of the disease. This is particularly useful for patients who suffer flu-like symptoms from other RRMS therapies as an alternative.

Interferon beta and glatiramer acetate therapy

Interferon beta and glatiramer acetate have been mainstays of treatment in relapsingremitting multiple sclerosis for two decades. Remarkable advances in our understanding of immune function and dysfunction as well as increasingly sophisticated clinical trial design have stemmed from efforts to better understand these drugs. In this chapter, we review the history of their development and elaborate on known and theorized mechanisms of action. We describe the pivotal clinical trials that have led to their widespread use. We evaluate the clinical use of the drugs including tolerability, side effects, and efficacy measures. Finally, we look to the future of interferon beta and glatiramer acetate in the context of an ever growing armamentarium of treatments for relapsing remitting multiple sclerosis.

Disease-specific therapy of idiopathic inflammatory demyelinating disorders

Central nervous system idiopathic inflammatory demyelinating disorders are a heterogenous group of diseases that share inflammation and demyelination as key features. Although the exact pathophysiology remains to be fully unveiled, these conditions are challenging to clinicians who seek specific therapeutic options for their patients. For two of these conditions, multiple sclerosis and neuromyelitis optica, there are now several possible therapies in an ever-evolving field. This review will touch on the various idiopathic inflammatory demyelinating disorders and discuss the various treatment options currently available.

Clinical utility of glatiramer acetate in the management of relapse frequency in multiple sclerosis

Glatiramer acetate (GA) represents one of the most common disease-modifying therapies for multiple sclerosis. GA is currently approved for patients at high risk of developing clinically definite multiple sclerosis (CDMS) after having experienced a well-defined first clinical episode (clinically isolated syndrome or CIS) and for patients with relapsing-remitting multiple sclerosis (RRMS). GA’s efficacy and effectiveness to reduce relapse frequency have been proved in placebo-controlled and observational studies. Comparative trials have also confirmed the lack of significant differences over other choices of treatment in the management of relapse frequency, and long-term studies have supported its effect at extended periods of time. Additionally, RRMS patients with suboptimal response to interferon β may benefit from reduced relapse rate after switching to GA, and those with clinically isolated syndrome may benefit from delayed conversion to CDMS. All these results, together with its proven long-term safety and positive effect on patients’ daily living, support the favorable risk-benefit of GA for multiple sclerosis treatment.

Glatiramer acetate antibodies, gene expression and disease activity in multiple sclerosis

BACKGROUND

Glatiramer acetate (GA) treatment suppresses disease activity in multiple sclerosis (MS). The immunological response to treatment may differ in patients who are stable on GA therapy and patients with breakthrough disease activity, but the results of previous studies are inconsistent.

OBJECTIVES

We studied the immunological response to GA and its relationship with disease activity.

METHODS

Anti-GA antibodies in plasma and the expression of genes encoding cytokines and T-cell-polarizing transcription factors in blood cells were analysed by flow cytometric bead array and polymerase chain reaction (PCR) analysis in 39 untreated and 29 GA-treated relapsing-remitting MS patients. Definition of breakthrough disease was based on the occurrence of relapses, disability progression, or gadolinium (Gd)-enhanced MRI.

RESULTS

The expression of T helper type 1 (Th1) and Th17 cytokines and transcription factors was reduced during long-term treatment, but there was no relationship between the expression of cytokines and transcription factors and anti-GA antibodies. High expression of mRNA encoding GATA3 and lymphotoxin-β (LT-β) was associated with low disease activity in Gd-enhanced MRI studies. None of the variables studied were associated with clinical disease activity. GA treatment resulted in the development of IgG and IgG4 anti-GA antibodies during the first months of treatment, persisting during long-term treatment.

CONCLUSIONS

The observed relationship between the expression of mRNA encoding GATA3 and LT-β expression and MRI disease activity deserves further analysis in future studies. The development of anti-GA antibodies was observed in all patients treated with GA, but this was not related with measures of cellular immunity, clinical or MRI disease activity.

Glatiramer acetate-specific antibody titres in patients with relapsing / remitting multiple sclerosis and in experimental autoimmune encephalomyelitis

Glatiramer acetate (GA) is an immunomodulatory drug approved for the treatment of clinically isolated syndrome (CIS) and relapsing/remitting multiple sclerosis (RRMS). As an antigen-based therapy, GA induces GA-specific antibodies in treated patients and animals. GA-specific antibodies do not neutralize therapeutic effects on relapses and disability. Rather, it has been suggested that GA-specific antibodies may be associated with improved clinical outcomes. We evaluated antibody responses in eight patients with RRMS treated with GA for 15 months and antibody responses in GA-treated C57BL/6 mice before and after induction of experimental autoimmune encephalomyelitis (EAE). There were no significant differences from pretreatment levels of total IgE or GA-specific IgE in patients with RRMS. Total IgG1, IgG3 and GA-specific IgG4 were significantly increased at 15 months of GA treatment. Antibody type and titre were not associated with clinical outcomes, i.e. expanded disability status scale (EDSS) score, disease burden on magnetic resonance images (MRI) or clinical relapses. In contrast, mice with EAE showed a marked increase in GA-specific IgE and GA-specific IgG1 antibody responses. GA-treated mice demonstrated improved clinical symptoms and lower mortality than untreated controls. Our results suggest that antibody responses to GA are heterogeneous among patients with RRMS, with no apparent association between antibody response and clinical outcomes. Clinical improvements in EAE-induced GA-treated mice suggest that GA-specific IgE and IgG1 may contribute to GA treatment effects in EAE.

Glatiramer acetate in the treatment of multiple sclerosis: emerging concepts regarding its mechanism of action

Glatiramer acetate is a synthetic, random copolymer widely used as a first-line agent for the treatment of relapsing-remitting multiple sclerosis (MS). While earlier studies primarily attributed its clinical effect to a shift in the cytokine secretion of CD4+ T helper (T(h)) cells, growing evidence in MS and its animal model, experimental autoimmune encephalomyelitis (EAE), suggests that glatiramer acetate treatment is associated with a broader immunomodulatory effect on cells of both the innate and adaptive immune system. To date, glatiramer acetate-mediated modulation of antigen-presenting cells (APC) such as monocytes and dendritic cells, CD4+ T(h) cells, CD8+ T cells, Foxp3+ regulatory T cells and antibody production by plasma cells have been reported; in addition, most recent investigations indicate that glatiramer acetate treatment may also promote regulatory B-cell properties. Experimental evidence suggests that, among these diverse effects, a fostering interplay between anti-inflammatory T-cell populations and regulatory type II APC may be the central axis in glatiramer acetate-mediated immune modulation of CNS autoimmune disease. Besides altering inflammatory processes, glatiramer acetate could exert direct neuroprotective and/or neuroregenerative properties, which could be of relevance for the treatment of MS, but even more so for primarily neurodegenerative disorders, such as Alzheimer's or Parkinson's disease. In this review, we provide a comprehensive and critical overview of established and recent findings aiming to elucidate the complex mechanism of action of glatiramer acetate.

Managing relapsing–remitting multiple sclerosis following first drug failure

SUMMARY IFN-β and glatiramer acetate are the usual first-line treatments for cases of relapsing–remitting multiple sclerosis. As both of these agents are only partially effective in controlling disease activity, ‘breakthrough’ disease is common. Deciding how much breakthrough constitutes a treatment failure necessitating a switch in therapy is now a common problem that most clinicians will encounter in practice. In this article we will discuss the approach to deciding when treatment failure occurs and the strategies that can be used to tackle this problem.

Definitions of breakthrough disease and second-line agents

Conventional disease-modifying agents are only moderately effective, so breakthrough disease activity is commonly seen. The evidence from randomized clinical trials and real-world observational data supporting the use of the second-line agents natalizumab, mitoxantrone, and cyclophosphamide are reviewed. Potential future treatment options are also discussed. Management algorithms for breakthrough disease are outlined.

Recent insights into the mechanism of action of glatiramer acetate

Glatiramer acetate (GA, Copaxone®, co-polymer 1) is an immunomodulatory therapy approved in 1996 by the United States Food and Drug Administration for treatment of relapsing-remitting multiple sclerosis. GA has a good safety profile, moderate efficacy, and a unique mode of action. Recent evidence in an animal model of MS, experimental autoimmune encephalomyelitis (EAE), suggests that GA effects on NK cells and B cells may contribute to therapeutic efficacy. We review the mechanism of action of GA, with particular focus on recent data suggesting a role for regulatory B cells.

Disease biomarkers in multiple sclerosis: potential for use in therapeutic decision making

Multiple sclerosis (MS) is an autoimmune disorder of the brain and spinal cord that predominantly affects white matter. MS has a variable clinical presentation and has no 'diagnostic' laboratory test; this often results in delays to definite diagnosis. In confronting the disease, early diagnosis and appropriate, timely therapeutic intervention are critical factors in ensuring favorable long-term outcomes. The availability of reliable biomarkers could radically alter our management of MS at critical phases of the disease spectrum. Identification of markers that could predict the development of MS in high-risk populations would allow for intervention strategies that may prevent evolution to definite disease. Work with anti-myelin antibodies and the ongoing analysis of microarray gene expression have thus far not yielded biomarkers that predict future disease development. Similarly, extensive studies with serum and cerebrospinal fluid (CSF) have not yielded a disease-specific and sensitive diagnostic biomarker for MS. Establishment of disease diagnosis always leads to questions about long-term prognosis because in an individual patient the natural history of the disease is clinically unpredictable. Biomarkers that correlate with myelin loss, spinal cord disease, grey matter and subcortical demyelination need to be developed in order to accurately predict the disease course. The bulk of effort in biomarker development in MS has been concentrated in the area of monitoring disease activity. At present, a disease 'activation' panel of CSF biomarkers would include the following: interleukin-6 or its soluble receptor, nitric oxide and nitric oxide synthase, osteopontin, and fetuin-A. Although disease activity in MS is predominantly inflammatory, disease progression is likely to be the result of neurodegeneration. Therefore, the roles of proteins indicative of neuronal, axonal, and glial loss such as neurofilaments, tau, 14-3-3 proteins, and N-acetylaspartate are all under investigation, as are proteins affecting remyelination and regeneration, such as Nogo-A. With the increasing awareness of cognition dysfunction in MS, molecules such as apolipoprotein and proteins in the amyloid precursor protein pathway implicated in dementia are also being examined. Serum biomarkers that help monitor therapeutic efficacy such as the titer of antibody to beta-interferon, a first-line medication in MS, are established in clinical practice. Ongoing work with biomarkers that reflect drug bioavailability and factors that distinguish between medication responders and nonresponders are also under investigation. The discovery of new biomarkers relies on applying advances in proteomics along with microarray gene and antigen analysis and will hopefully result in the establishment of specific biomarkers for MS.

Benefits of glatiramer acetate in the treatment of relapsing-remitting multiple sclerosis

Relapsing-remitting multiple sclerosis is a chronic, progressive disorder marked by repeated exacerbations that lead to increases in neurological disability. Glatiramer acetate and the IFN-betas are recommended as first-line agents for relapsing-remitting multiple sclerosis owing to their potential to reduce frequency and severity of relapses, decrease development of new brain lesions and delay permanent disability. After three decades of study, the preponderance of the evidence suggests that the efficacy of glatiramer acetate is similar to the IFN-betas and new data collected in more naturalistic settings suggest that it may provide improved quality of life, increased productivity and cost-effectiveness. This article will review this evidence including data from very recent head-to-head clinical trials and pharmacoeconomic analyses of cost-effectiveness.

Neutralizing antibodies to interferon-beta and other immunological treatments for multiple sclerosis: prevalence and impact on outcomes

Biopharmaceuticals can induce antibodies, which interact with and neutralize the therapeutic effect of such drugs and are therefore termed neutralizing antibodies (NAbs). In the treatment of multiple sclerosis, NAbs against interferon (IFN)-beta and natalizumab have been recognized. The prevalence of NAbs against different IFNbeta preparations varies widely, mainly depending on the product but also on other factors such as amino acid sequence variations, glycosylation, formulation, route and frequency of application, dose, duration of treatment and patient characteristics (human leukocyte antigen [HLA] status). IFNbeta-1a given intramuscularly induces significantly less NAbs than any other IFNbeta formulation. The longitudinal development of NAbs also differs between IFNbeta preparations, with higher reversion rates in IFNbeta-1b-treated compared with IFNbeta-1a-treated patients. The negative effect of NAbs on various outcome measures is very consistent across many studies, specifically when observation periods are longer than 2 years. NAbs against natalizumab occur less frequently (6%) and, like NAbs against IFNbeta, they are associated with a loss of clinical and radiological efficacy of the drug.

Glatiramer acetate immunization induces specific antibody and cytokine responses in ALS patients

We assessed humoral and cytokine responses in monthly plasma samples from ALS patients who received glatiramer acetate (GA) immunization every day or every other week, or remained untreated (control) from a six-month phase II trial. Samples were evaluated by GA-specific ELISA assays for detection of combined immunoglobulin (Ig) classes (IgM,A,G), IgG alone, and IgG subclasses (IgG1, IgG2, IgG3, and IgG4). T-helper (Th) type 1 and 2 (Th1 and Th2) cytokine levels were determined by flow cytometric cytokine bead arrays. Fourteen of 21 GA-immunized patients produced anti-GA Ig responses. Those treated every day produced anti-GA responses within one month, while those treated every other week exhibited responses by month two. All anti-GA IgG subclass concentrations were increased in excess of 4.2-fold in plasma from treated patients, and anti-GA IgG1 comprised the majority of the humoral response. Mean plasma cytokine levels were statistically indistinguishable between treatment regimens; however, stratification by patient and time on study showed more prevalent trends in changes of Th1 or Th2 cytokine levels following GA treatment every other week or every day, respectively. These data show significant humoral responses and cytokine trends following GA immunization in ALS patients.

Adaptive immune neuroprotection in G93A-SOD1 amyotrophic lateral sclerosis mice

Background

Innate neuroimmune dysfunction is a pathobiological feature of amyotrophic lateral sclerosis (ALS). However, links, if any, between disease and adaptive immunity are poorly understood. Thus, the role of T cell immunity in disease was investigated in human G93A superoxide dismutase 1 (SOD1) transgenic (Tg) mice and subsequently in ALS patients.

Methods and Findings

Quantitative and qualitative immune deficits in lymphoid cell and T cell function were seen in G93A-SOD1 Tg mice. Spleens of Tg animals showed reductions in size, weight, lymphocyte numbers, and morphological deficits at terminal stages of disease compared to their wild-type (Wt) littermates. Spleen sizes and weights of pre-symptomatic Tg mice were unchanged, but deficits were readily seen in T cell proliferation coincident with increased annexin-V associated apoptosis and necrosis of lymphocytes. These lymphoid deficits paralleled failure of Copolymer-1 (COP-1) immunization to affect longevity. In addition, among CD4⁺ T cells in ALS patients, levels of CD45RA⁺ (naïve) T cells were diminished, while CD45RO⁺ (memory) T cells were increased compared to age-matched caregivers. In attempts to correct mutant SOD1 associated immune deficits, we reconstituted SOD1 Tg mice with unfractionated naïve lymphocytes or anti-CD3 activated CD4⁺CD25⁺ T regulatory cells (Treg) or CD4⁺CD25⁻ T effector cells (Teff) from Wt donor mice. While naive lymphocytes failed to enhance survival, both polyclonal-activated Treg and Teff subsets delayed loss of motor function and extended survival; however, only Treg delayed neurological symptom onset, whereas Teff increased latency between disease onset and entry into late stage.

Conclusions

A profound and progressive immunodeficiency is operative in G93A-SOD1 mice and is linked to T cell dysfunction and the failure to elicit COP-1 neuroprotective immune responses. In preliminary studies T cell deficits were also observed in human ALS. These findings, taken together, suggest caution in ascribing vaccination outcomes when these animal models of human ALS are used for study. Nonetheless, the abilities to improve neurological function and life expectancy in G93A-SOD1 Tg mice by reconstitution with activated T cells do provide opportunities for therapeutic intervention.

Mechanism of action of glatiramer acetate in treatment of multiple sclerosis

Glatiramer acetate (GA) (Copolymer-1, Copaxone, Teva, Israel, YEAK) is a polypeptide-based therapy approved for the treatment of relapsing-remitting multiple sclerosis. Most investigations have attributed the immunomodulatory effect of GAs to its capability to alter T-cell differentiation. Specifically, GA treatment is believed to promote development of Th2-polarized GA-reactive CD4(+) T-cells, which may dampen neighboring inflammation within the central nervous system. Recent reports indicate that the deficiency in CD4(+)CD25(+)FoxP3(+) regulatory T-cells in multiple sclerosis is restored by GA treatment. GA also exerts immunomodulatory activity on antigen presenting cells, which participate in innate immune responses. These new findings represent a plausible explanation for GA-mediated T-cell immune modulation and may provide useful insight for the development of new and more effective treatment options for multiple sclerosis.