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

Implications of glycosylation for the development of selected cytokines and their derivatives for medical use

Cytokines are important regulators of immune responses, making them attractive targets for autoimmune diseases and cancer therapeutics. Yet, the significance of cytokine glycosylation remains underestimated. Many cytokines carry N- and O-glycans and some even undergo C-mannosylation. Recombinant cytokines produced in heterologous host cells may lack glycans or exhibit a different glycosylation pattern such as varying levels of galactosylation, sialylation, fucosylation or xylose addition compared to their human counterparts, potentially impacting critical immune interactions. We focused on cytokines that are currently utilized or designed in advanced therapeutic formats, including immunocytokines, fusokines, engager cytokines, and genetically engineered 'supercytokines.' Despite the innovative designs of these cytokine derivatives, their glycosylation patterns have not been extensively studied. By examining the glycosylation of the human native cytokines, G-CSF and GM-CSF, interferons β and γ, TNF-α and interleukins-2, -3 -4, -6, -7, -9, -12, -13, -15, -17A, -21, and - 22, we aim to assess its potential impact on their therapeutic derivatives. Understanding the glycosylation of the native cytokines could provide critical insights into the safety, efficacy, and functionality of these next-generation cytokine therapies, affecting factors such as stability, bioactivity, antigenicity, and half-life. This knowledge can guide the choice of optimal expression hosts for production and advance the development of effective cytokine-based therapeutics and synthetic immunology drugs.

Development of IFNβ-1a versions with reduced immunogenicity and full in vitro biological activity for the treatment of multiple sclerosis

IFNβ (recombinant interferon Beta) has been widely used for the treatment of Multiple sclerosis for the last four decades. Despite the human origin of the IFNβ sequence, IFNβ is immunogenic, and unwanted immune responses in IFNβ-treated patients may compromise its efficacy and safety in the clinic. In this study, we applied the DeFT (De-immunization of Functional Therapeutics) approach to producing functional, de-immunized versions of IFNβ-1a. Two de-immunized versions of IFNβ-1a were produced in CHO cells and designated as IFNβ-1a(VAR1) and IFNβ-1a(VAR2). First, the secondary and tertiary protein structures were analyzed by circular dichroism spectroscopy. Then, the variants were also tested for functionality. While IFNβ-1a(VAR2) showed similar in vitro antiviral activity to the original protein, IFNβ-1a(VAR1) exhibited 40% more biological potency. Finally, in vivo assays using HLA-DR transgenic mice revealed that the de-immunized variants showed a markedly reduced immunogenicity when compared to the originator.

Interferon beta-1a sc at 25 years: a mainstay in the treatment of multiple sclerosis over the period of one generation

INTRODUCTION

Interferon beta (IFN beta) preparations are an established group of drugs used for immunomodulation in patients with multiple sclerosis (MS). Subcutaneously (sc) applied interferon beta-1a (IFN beta-1a sc) has been in continuous clinical use for 25 years as a disease-modifying treatment.

AREAS COVERED

Based on data published since 2018, we discuss recent insights from analyses of the pivotal trial PRISMS and its long-term extension as well as from newer randomized studies with IFN beta-1a sc as the reference treatment, the use of IFN beta-1a sc across the patient life span and as a bridging therapy, recent data regarding the mechanisms of action, and potential benefits of IFN beta-1a sc regarding vaccine responses.

EXPERT OPINION

IFN beta-1a sc paved the way to effective immunomodulatory treatment of MS, enabled meaningful insights into the disease process, and remains a valid therapeutic option in selected vulnerable MS patient groups.

Specific sequence mutations in a long-lasting rhIFN-α2b version reduce in vitro and in vivo immunogenicity and increase in vitro protein stability

For decades, recombinant human interferon alpha (rhIFN-α2b) has been used to treat emerging and chronic viral diseases. However, rhIFN-α2b is immunogenic and has a short in vivo half-life. To solve these limitations, two long-lasting hyperglycosylated proteins with reduced immunogenicity were developed and designated as 4N-IFN(VAR1) and 4N-IFN(VAR3). Here, we continue to study the relevant characteristics of these therapeutic candidates. Thus, we demonstrated that both de-immunized IFN versions elicited significantly lower neutralizing antibody responses than the original molecule in HLA-DR1 transgenic mice, confirming our previous in vitro protein immunogenicity data. Also, we found that these biobetters exhibited remarkable stability when exposed to different physical factors that the protein product may encounter during its production process and storage, such as low pH, thermal stress, and repeated freezing/thawing cycles. Taking into consideration our previous and present results, 4N-IFN(VAR1) and 4N-IFN-4N(VAR3) appear to be valuable candidates for the treatment of human viral diseases.

Chronic Neurological Disorders: Genetic and Epigenetic Markers for Monitoring of Pharmacotherapy

Introduction

Chronic neurological diseases are a major cause of mortality and morbidity in the world. With increasing life expectancy in the developing world, the incidence and prevalence of these diseases are predicted to rise even further. This has also contributed to an increase in disability-adjusted life years (DALYs) for noncommunicable diseases. Treatment for such diseases also poses a challenge with multiple genetic and epigenetic factors leading to a varied outcome. Personalization of treatment is one way that treatment outcome/prognosis of disease can be improved, and pharmacogenomics plays a significant role in this context.

Methodology

This article reviewed the evidence pertaining to the association of genetic and epigenetic markers with major neurological disorders like multiple sclerosis (MS), Alzheimer's disease (AD), and Parkinson's disease (PD), which are a major source of burden among neurological disorders. Types of studies included are peer-reviewed original research articles from the PubMed database (1999-2018).

Results

This study compiled data regarding specific genetic and epigenetic markers with a significant correlation between the clinical diagnosis of the disease and prognosis of therapy from 65 studies. In a single platform, this review highlights the clues to some vital questions, such as why interferon beta (IFN-β) therapy fails to improve symptoms in all MS patients? why cholinesterase inhibitors fail to improve cognitive impairment in a subset of people suffering from AD? or why some individuals on levodopa (L-DOPA) for PD suffer from side-effects ranging from dyskinesia to hallucination while others do not?

Conclusion

This article summarizes the genetic and epigenetic factors that may either require monitoring or help in deciding future pharmacotherapy in a patient suffering from MS, AD, and PD. As the health care system develops and reaches newer heights, we expect more and more of these biomarkers to be used as pharmacotherapeutic outcome indicators.

Interferons and Multiple Sclerosis: Lessons from 25 Years of Clinical and Real-World Experience with Intramuscular Interferon Beta-1a (Avonex)

Recombinant interferon (IFN) β-1b was approved by the US Food and Drug Administration as the first disease-modifying therapy (DMT) for multiple sclerosis (MS) in 1993. Since that time, clinical trials and real-world observational studies have demonstrated the effectiveness of IFN therapies. The pivotal intramuscular IFN β-1a phase III trial published in 1996 was the first to demonstrate that a DMT could reduce accumulation of sustained disability in MS. Patient adherence to treatment is higher with intramuscular IFN β-1a, given once weekly, than with subcutaneous formulations requiring multiple injections per week. Moreover, subcutaneous IFN β-1a is associated with an increased incidence of injection-site reactions and neutralizing antibodies compared with intramuscular administration. In recent years, revisions to MS diagnostic criteria have improved clinicians' ability to identify patients with MS and have promoted the use of magnetic resonance imaging (MRI) for diagnosis and disease monitoring. MRI studies show that treatment with IFN β-1a, relative to placebo, reduces T2 and gadolinium-enhancing lesions and gray matter atrophy. Since the approval of intramuscular IFN β-1a, a number of high-efficacy therapies have been approved for MS, though the benefit of these high-efficacy therapies should be balanced against the increased risk of serious adverse events associated with their long-term use. For some subpopulations of patients, including pregnant women, the safety profile of IFN β formulations may provide a particular benefit. In addition, the antiviral properties of IFNs may indicate potential therapeutic opportunities for IFN β in reducing the risk of viral infections such as COVID-19.

Effectiveness of glatiramer acetate in neutralizing antibody-positive patients previously treated with interferon-β

BACKGROUND

Some patients with multiple sclerosis who are treated with interferon-β(IFNβ) develop neutralizing antibodies (NAbs), which reduce or abolish the therapeutic effects of the treatment. These patients are usually switched to a non-IFNβ treatment, such as glatiramer acetate (GA). It is unknown whether a patient's previous disease activity in combination with their NAb-status can provide further insights on their risk of future disease activity. Consequently, we investigated treatment outcomes in patients switching from IFNβ to GA according to NAb-status and clinical disease activity, while on IFNβ.

METHODS

We identified all patients switching from IFNβ to GA and having information on NAb-status from the Danish Multiple Sclerosis Registry and compared treatment outcomes while on GA according to previous disease activity and the presence of NAbs.

RESULTS

We included 568 patients in the study: 107 NAb-negative patients switched due to adverse events (group 1), 24 NAb-negative patients switched with disease activity (group 2), 397 NAb-positive patients switched without disease activity (group 3) and 40 NAb-positive patients switched with disease activity (group 4). Compared to the reference (group 1), group 2 had an increased risk of future relapses (HR 1.79 95% Confidence interval (CI): 1.00-3.19). Group 3 showed a trend of a lower risk of future relapses (HR 0.74, 95%CI: 0.53-1.04). Group 4 had, on average, a similar risk of future relapses (HR 1.15 95% CI: 0.69-1.92). Similarly, group 2 had a higher probability of treatment discontinuation due to disease activity compared to the other groups.

CONCLUSION

While on GA, patients switched from IFNβ in the context of disease activity and no NAbs had the highest risk of future disease activity, while NAb positive patients without previous activity had the lowest. We did not find any average difference between NAb-positive patients switching in a context of disease activity and NAb-negative patients switched due to adverse events, although carefulness in the interpretation of this result is advised.

Molecular biomarkers in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory-neurodegenerative disease of the central nervous system presenting with significant inter- and intraindividual heterogeneity. However, the application of clinical and imaging biomarkers is currently not able to allow individual characterization and prediction. Complementary, molecular biomarkers which are easily quantifiable come from the areas of immunology and neurobiology due to the causal pathomechanisms and can excellently complement other disease characteristics. Only a few molecular biomarkers have so far been routinely used in clinical practice as their validation and transfer take a long time. This review describes the characteristics that an ideal MS biomarker should have and the challenges of establishing new biomarkers. In addition, clinically relevant and promising biomarkers from the blood and cerebrospinal fluid are presented which are useful for MS diagnosis and prognosis as well as for the assessment of therapy response and side effects.

Different Interferon Beta Preparations Induce the Same Qualitative Immune Response in Human Skin

Interferon beta (IFNβ) is used as a first-line treatment for multiple sclerosis (MS) and is injected intramuscularly or subcutaneously (s.c.). The subcutaneous route is considered more immunogenic as it is associated with increased antidrug antibody-positive patients. The skin contains dendritic cells (DCs) and it is unclear whether these contribute to immunogenicity. To assess the effect of IFNβ on skin-resident cells, IFNβ was injected intradermally (i.d.) ex vivo using a human skin explant model or s.c. in vivo in MS patients. Ex vivo, intradermal IFNβ injections reduced migration and enhanced surface CD86 expression of dermal DCs, and an increased expression of HLA-DR⁺ was observed in skin biopsies taken after subcutaneous IFNβ injection (in vivo). In both models, IFNβ elevated the expression of several inflammatory cytokines when compared to the control biopsies. Our results show that 3 different IFNβ preparations, normalized in dose and injection site, induce similar immune responses, suggesting that the differences in immunogenicity are likely due to the route and frequency of administration.

Anti-Drug Antibodies: Emerging Approaches to Predict, Reduce or Reverse Biotherapeutic Immunogenicity

The development of anti-drug antibodies (ADAs) following administration of biotherapeutics to patients is a vexing problem that is attracting increasing attention from pharmaceutical and biotechnology companies. This serious clinical problem is also spawning creative research into novel approaches to predict, avoid, and in some cases even reverse such deleterious immune responses. CD4⁺ T cells are essential players in the development of most ADAs, while memory B-cell and long-lived plasma cells amplify and maintain these responses. This review summarizes methods to predict and experimentally identify T-cell and B-cell epitopes in therapeutic proteins, with a particular focus on blood coagulation factor VIII (FVIII), whose immunogenicity is clinically significant and is the subject of intensive current research. Methods to phenotype ADA responses in humans are described, including T-cell stimulation assays, and both established and novel approaches to determine the titers, epitopes and isotypes of the ADAs themselves. Although rational protein engineering can reduce the immunogenicity of many biotherapeutics, complementary, novel approaches to induce specific tolerance, especially during initial exposures, are expected to play significant roles in future efforts to reduce or reverse these unwanted immune responses.

Neutralizing Antibodies Against Interferon-Beta in Korean Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE

Patients treated with interferon-beta (IFN-β) can develop neutralizing antibodies (NAbs) against IFN-β that can negatively affect the therapeutic response. This study assessed the prevalence of NAbs and the impact of NAb positivity on the therapeutic response to IFN-β in Korean patients with multiple sclerosis (MS).

METHODS

This was a multicenter study involving 150 MS patients from 9 Korean medical centers who were treated with IFN-β for at least 6 months. Sera that had not been influenced by acute treatment were assessed for NAbs using a luciferase reporter gene assay. To evaluate the association between persistent positivity for NAbs and disease activity, NAbs were tested at 2 different time points in 75 of the 150 patients. Disease activity was defined as the presence of clinical exacerbations and/or active MRI lesions during a 1-year follow-up after NAb positivity was confirmed.

RESULTS

NAbs were found in 39 of the 150 (26%) MS patients: 30 of the 85 (35%) who were treated with subcutaneous IFN-β-1b, 9 of the 60 (15%) who were treated with subcutaneous IFN-β-1a, and 0 of the 5 (0%) who were treated with intramuscular IFN-β-1a. Thirty of the 39 patients exhibiting NAb positivity were tested at different time points, and 20 of them exhibited persistent NAb positivity. Disease activity was observed more frequently in patients with persistent NAb positivity than in those with transient positivity or persistent negativity [16/20 (80%) vs. 4/55 (7%), respectively; p<0.001]. When disease activity was compared between patients with persistent and transient NAb positivity, the difference was unchanged and remained statistically significant [16/20 (80%) vs. 2/10 (20%), p=0.004].

CONCLUSIONS

These results further support that persistent NAb positivity is associated with disease activity in MS patients treated with IFN-β.

Cross-reactivity of antibodies against interferon beta in multiple sclerosis patients and interference of the JAK-STAT signaling pathway

Interferon beta (IFNβ) therapy has immunogenic properties and induces the development of neutralizing antibodies (NAbs). From the extensive literature focused in the development of NAbs in multiple sclerosis (MS) patients, their ability to cross-react has been deficiently evaluated, despite having important consequences in the clinical practice. Here, the relation between the cross-reactivity and the NAbs titers has been evaluated in MS patients, by inhibition of the antiviral activity of IFNβ by bioassay and through the interference with the activation of the IFNß pathway (JAK-STAT), by phosphoflow. Thus, patients with intermediate-high titers of NAbs, determined by bioassay, had a 79-fold increased risk of cross-reactivity compared to patients with low titers. The cross-reactivity is also demonstrated because NAbs positive sera were able to decrease significantly the activation of pSTAT1 achieved by other different IFNβ molecules in the cells patients. Besides, a linear relationship between the STAT1 phosphorylation and NAbs titers was found. The study demonstrates that cross-reactivity increases with the titer of antibodies, which has important implications in clinical practice when switching the treatment. The direct relationship between the NAbs titer and the activation of STAT1 suggest that its determination could be an indirect method to identify the presence of NAbs.

Persistency of Neutralizing Anti-Interferon-β Antibodies in Patients with Multiple Sclerosis Treated with Subcutaneous Interferon-β Depends on Antibody Titers, IgG Subclasses, and Affinity Maturation

Neutralizing antibodies may affect interferon (IFN)-β treatment efficacy, but mechanisms of neutralizing anti-drug antibody (ADA) evolution are not fully elucidated. We investigated the relationship between ADA titers, IgG subclass profile, and binding affinity with the development and persistency of neutralizing ADA in relapsing-remitting multiple sclerosis (MS) patients treated with subcutaneous IFN-β. A total of 94 patients, who had blood sampling at months 6, 12, 24, and 36 during IFN-β therapy, were included into this retrospective study and stratified to the following: non-neutralizing, transient, and persistent neutralizing ADA status. Patients without or with transient neutralizing ADA displayed predominantly IgG₁ and IgG₃ subclasses, lower ADA titers, and antibody binding affinity compared with patients having persistent neutralizing ADA, in whom the predominant IgG subclasses were IgG₂ and IgG₄. Overall, ADA binding affinity positively correlated with IgG₄ and neutralizing ADA titers, but negatively with IgG₃ titers. Persistency of neutralizing ADA was predicted by their titers at month 24 and month 36 of treatment and by an increase of antibody affinity within the second year of IFN-β treatment. The humoral immune response to IFN-β observed in MS patients as a result of IFN-β therapy is a multifactorial process that is influenced by ADA titers, affinity maturation, and IgG subclass switching.

Clinical practice of analysis of anti-drug antibodies against interferon beta and natalizumab in multiple sclerosis patients in Europe: A descriptive study of test results

Antibodies against biopharmaceuticals (anti-drug antibodies, ADA) have been a well-integrated part of the clinical care of multiple sclerosis (MS) in several European countries. ADA data generated in Europe during the more than 10 years of ADA monitoring in MS patients treated with interferon beta (IFNβ) and natalizumab have been pooled and characterized through collaboration within a European consortium. The aim of this study was to report on the clinical practice of ADA testing in Europe, considering the number of ADA tests performed and type of ADA assays used, and to determine the frequency of ADA testing against the different drug preparations in different countries. A common database platform (tranSMART) for querying, analyzing and storing retrospective data of MS cohorts was set up to harmonize the data and compare results of ADA tests between different countries. Retrospective data from six countries (Sweden, Austria, Spain, Switzerland, Germany and Denmark) on 20,695 patients and on 42,555 samples were loaded into tranSMART including data points of age, gender, treatment, samples, and ADA results. The previously observed immunogenic difference among the four IFNβ preparations was confirmed in this large dataset. Decreased usage of the more immunogenic preparations IFNβ-1a subcutaneous (s.c.) and IFNβ-1b s.c. in favor of the least immunogenic preparation IFNβ-1a intramuscular (i.m.) was observed. The median time from treatment start to first ADA test correlated with time to first positive test. Shorter times were observed for IFNβ-1b-Extavia s.c. (0.99 and 0.94 years) and natalizumab (0.25 and 0.23 years), which were introduced on the market when ADA testing was already available, as compared to IFNβ-1a i.m. (1.41 and 2.27 years), IFNβ-1b-Betaferon s.c. (2.51 and 1.96 years) and IFNβ-1a s.c. (2.11 and 2.09 years) which were available years before routine testing began. A higher rate of anti-IFNβ ADA was observed in test samples taken from older patients. Testing for ADA varies between different European countries and is highly dependent on the policy within each country. For drugs where routine monitoring of ADA is not in place, there is a risk that some patients remain on treatment for several years despite ADA positivity. For drugs where a strategy of ADA testing is introduced with the release of the drug, there is a reduced risk of having ADA positive patients and thus of less efficient treatment. This indicates that potential savings in health cost might be achieved by routine analysis of ADA.

De-immunized and Functional Therapeutic (DeFT) versions of a long lasting recombinant alpha interferon for antiviral therapy

Interferon α (IFN-α) exerts potent antiviral, immunomodulatory, and antiproliferative activity and have proven clinical utility in chronic hepatitis B and C virus infections. However, repeated IFN-α administration induces neutralizing antibodies (NAb) against the therapeutic in a significant number of patients. Associations between IFN-α immunogenicity and loss of efficacy have been described. So as to improve the in vivo biological efficacy of IFN-α, a long lasting hyperglycosylated protein (4N-IFN) derived from IFN-α2b wild type (WT-IFN) was developed. However, in silico analysis performed using established in silico methods revealed that 4N-IFN had more T cell epitopes than WT-IFN. In order to develop a safer and more efficient IFN therapy, we applied the DeFT (De-immunization of Functional Therapeutics) approach to producing functional, de-immunized versions of 4N-IFN. Using the OptiMatrix in silico tool in ISPRI, the 4N-IFN sequence was modified to reduce HLA binding potential of specific T cell epitopes. Following verification of predictions by HLA binding assays, eight modifications were selected and integrated in three variants: 4N-IFN(VAR1), (VAR2) and (VAR3). Two of the three variants (VAR1 and VAR3) retained anti-viral function and demonstrated reduced T-cell immunogenicity in terms of T-cell proliferation and Th1 and Th2 cytokine levels, when compared to controls (commercial NG-IFN (non-glycosylated), PEG-IFN, WT-IFN and 4N-IFN). It was previously demonstrated that N-glycosylation improved IFN-α pharmacokinetic properties. Here, we further reduce immunogenicity as measured in vitro using T cell assays and cytokine profiling by modifying the T cell epitope content of a protein (de-immunizing). Taking into consideration the present results and previously reported immunogenicity data for commercial IFN-α2b variants, 4N-IFN(VAR1) and 4N-IFN-4N(VAR3) appear to be promising candidates for improved IFN-α therapy of HCV and HBV.

Occurrence of Anti-Drug Antibodies against Interferon-Beta and Natalizumab in Multiple Sclerosis: A Collaborative Cohort Analysis

Immunogenicity of biopharmaceutical products in multiple sclerosis is a frequent side effect which has a multifactorial etiology. Here we study associations between anti-drug antibody (ADA) occurrence and demographic and clinical factors. Retrospective data from routine ADA test laboratories in Sweden, Denmark, Austria and Germany (Dusseldorf group) and from one research study in Germany (Munich group) were gathered to build a collaborative multi-cohort dataset within the framework of the ABIRISK project. A subset of 5638 interferon-beta (IFNβ)-treated and 3440 natalizumab-treated patients having data on at least the first two years of treatment were eligible for interval-censored time-to-event analysis. In multivariate Cox regression, IFNβ-1a subcutaneous and IFNβ-1b subcutaneous treated patients were at higher risk of ADA occurrence compared to IFNβ-1a intramuscular-treated patients (pooled HR = 6.4, 95% CI 4.9-8.4 and pooled HR = 8.7, 95% CI 6.6-11.4 respectively). Patients older than 50 years at start of IFNβ therapy developed ADA more frequently than adult patients younger than 30 (pooled HR = 1.8, 95% CI 1.4-2.3). Men developed ADA more frequently than women (pooled HR = 1.3, 95% CI 1.1-1.6). Interestingly we observed that in Sweden and Germany, patients who started IFNβ in April were at higher risk of developing ADA (HR = 1.6, 95% CI 1.1-2.4 and HR = 2.4, 95% CI 1.5-3.9 respectively). This result is not confirmed in the other cohorts and warrants further investigations. Concerning natalizumab, patients older than 45 years had a higher ADA rate (pooled HR = 1.4, 95% CI 1.0-1.8) and women developed ADA more frequently than men (pooled HR = 1.4, 95% CI 1.0-2.0). We confirmed previously reported differences in immunogenicity of the different types of IFNβ. Differences in ADA occurrence by sex and age are reported here for the first time. These findings should be further investigated taking into account other exposures and biomarkers.

Pharmacokinetic considerations in the treatment of multiple sclerosis with interferon-β

INTRODUCTION

Interferon-β (IFNβ) is well established as a disease-modifying treatment for patients with multiple sclerosis. Several preparations of the biopharmaceutical are available differing in protein structure, formulation, dose as well as frequency and route of administration. Recently, a pegylated form of IFNβ has been marketed.

AREAS COVERED

Following a PubMed database search, we provide an overview of what is presently known about the pharmacokinetics (PK) of IFNβ including its absorption, distribution, metabolism and elimination. Also, we discuss the association with clinically relevant issues such as treatment efficacy, adverse events and anti-drug antibodies.

EXPERT OPINION

IFNβ has a bioavailability of ∼ 30% after subcutaneous or intramuscular administration, shows peak serum concentrations within several hours, has a half-life of < 1 day and is eliminated by a renal and hepatic pathway. PK parameters do not substantially differ between the types of IFNβ and routes of administration; only pegylation of IFNβ results in substantially increased and prolonged PK. Although no clinical dose-effect relationship could be established, there is an association of IFNβ dose with magnetic resonance imaging outcome parameters. Furthermore, there is an association of IFNβ serum levels with the occurrence of adverse events and anti-drug antibodies.

High-dose intravenous interferon-beta in multiple sclerosis patients with high-titer neutralizing antibodies (HINABS II) - A pilot study

BACKGROUND

Neutralizing antibodies (NAb) against interferon-beta (IFNβ) affect its treatment efficacy. So far, there are no anti-NAb strategies available.

OBJECTIVES

To investigate if the repeated administration of high-dose IFNβ-1b intravenous in NAb positive multiple sclerosis (MS) patients induces tolerance and establishes IFNβ bioavailability as measured by the induction of myxovirus protein A (MxA).

METHODS

Nine MS patients with NAb titers >500 10-fold reduction units (TRU) received 1500μg IFNβ-1b intravenously once weekly over three months. Blood samples were collected at screening, monthly during the treatment period (before and four hours after IFNβ administration), and at follow-up after 6 months for determination of NAbs and MxA expression.

RESULTS

Median NAb titer at baseline was 1429TRU. NAb titers determined before each infusion did not significantly change over the treatment period and were not different at follow-up compared to baseline. However, NAb titers were significantly decreased four hours after IFNβ infusions (by roughly 50%) and MxA mRNA levels were significantly elevated reaching a median value of 206.

CONCLUSIONS

Weekly intravenous administration of IFNβ in patients with high NAb titers established its bioavailability, but failed to induce tolerance towards IFNβ.

Interferon-Beta: Neutralizing Antibodies, Binding Antibodies, Pharmacokinetics and Pharmacodynamics, and Clinical Outcomes

Antibodies to interferon-beta (IFNb) may occur during treatment with this drug and can be measured at several levels, the totality of antibodies referred to as antidrug antibodies (ADA) or binding antibodies, and in case of interference with the drug activity referred to as neutralizing antibodies (NAB). Antibodies can also interfere with the biological activity of IFNb as measured by pharmacodynamic markers. To get a complete picture of the interference between IFNb as a drug and the ADA, all the 3 above levels need to be considered. Furthermore, the interaction of these biomarkers changes over time with a shift of antibody properties with respect to immunoglobulin subtypes, affinity, and titers of antibodies. In case of persistent NAB, the clinical benefit of IFNb in the treatment of multiple sclerosis is abolished. In this report, the current knowledge on these issues will be reviewed. The data have been presented at a meeting in Coral Gables, Florida on April 18-21, 2012.

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.

Socio-economic aspects of the testing for antibodies in MS-patients under interferon therapy in Austria: a cost of illness study

BACKGROUND

According to EU-guidelines testing patients on interferon-beta (IFNb) for the presence of neutralising antibodies (NAb) is recommended; IFNb treatment efficacy of NAb-positive patients equals that of placebo-treated patients. Economic impact of NAb testing in MS patients has not been explored yet. The aim of this analysis is to estimate the impact of NAb testing in RRMS-patients on Austria׳s health-care-system.

METHODS

A decision-analytic model over 5 years was performed. The cost effectiveness of NAb testing versus no testing was evaluated. The model considers switching after relapse and withdrawal. All direct costs are based on Austrian data from 2013 and were discounted at 5% per year. The efficacy outcome measure was "relapse free". Clinical data and resource use were determined by literature.

RESULTS

Total costs for all Austrian MS-patients on IFNb-therapy with testing amount to 187,554,021€ over 5 years; without testing is 175,091,300 €. Costs per relapse avoided over 5 years were 90,075€ in the NAb testing arm, and 99,535€ in the no NAb test arm, resulting in a difference of 9460€ in favour of routine NAb testing. Considering all 3590 IFNb-treated patients 2082 relapses can be avoided in the NAb testing arm versus 1759 in the no-testing arm within 5 years. Testing for NAb leads to costs per relapse avoided of 18,015€ per year versus 19,907€ when no tests are done.

CONCLUSION

The results suggest that NAb testing reduces relapses and associated costs.

Detection of anti-cytokine antibodies and their clinical relevance

Cytokines regulate many aspects of cell growth and differentiation and play pivotal roles in the orchestration of immune defence against invading pathogens. Though 'self' proteins, they are potentially immunogenic and can give rise to anti-cytokine autoantibodies (aCA). The main foci of the article are a critical summary of the various methodologies applied for detecting and measuring aCA and a broad review of studies of the occurrence, characterization and clinical relevance of aCA in normal healthy individuals, patients with autoimmune diseases or microbial infections and aCA in patients whose disease is treated with recombinant cytokine products. The need for technical and methodological improvement of assays, including validation and standardization, together with approaches to harmonize calculation and reporting of results is also discussed.

BAb and MxA as functional biomarkers in routine clinical laboratories for the determination of anti-IFN-beta antibodies and their bioactivity levels in multiple sclerosis patients

In MS patients under IFNβ treatment to seek alternative treatments timely is important that anti-IFNβ antibodies and/or in vivo biologic activity loss detection in these. The most common diagnostic markers used for this purpose are BAb, Nab, and MxA. In this article, we aimed to establish the availability and feasibility of the correlation between BAb and MxA gene expression (mRNA) levels using evaluation of responses to IFNβ treatment for MS patients with a routine laboratory follow-up strategy in a major Turkish MS center. Bab seropositivity was determined in blood samples of 218 MS patients treated with different IFNβ preparations and MxA mRNA levels were measured in 128 patients among the total population. BAb seropositivity ratios to im INF-β 1a, scINF-β 1a, and sc INF-β 1b were 21.4%, 28.6%, and 70.4%, respectively (total 40%), and total loss of bioactivity (MxA mRNA) were 9.3%, 9.5%, and 11.6%, respectively (total 10.2%). The correlation between high BAb titers and low MxA mRNA levels was highly significant (P = 0.00003). Our data indicate that there is a good correlation between especially high BAbs levels and diminished MxA mRNA levels.

Deficient phosphorylation of Stat1 in leukocytes identifies neutralizing antibodies in multiple sclerosis patients treated with interferon-beta

BACKGROUND

Anti interferon-beta (IFN-β) neutralizing antibodies (NAb) affect efficacy of treatment of multiple sclerosis patients, but exactly when the detrimental effects of NAbs offset therapeutic efficacy is debated. Quantification of intracellular pathway-specific phosphorylation by phospho-specific flow cytometry (phosphoflow) is a promising tool for evaluation of these effects in primary immune cells from treated patients at the single-cell level.

METHOD

Samples for phosphoflow and gene expression changes were collected before administration of IFN-β and at four, six, and eight hours thereafter. Patients were NAb negative (n = 3) or were NAb positive with low/medium (n = 1) or high (n = 2) NAb titers. Levels of phosphorylation of six Stat transcription factors (pStat) in seven cell subtypes and expression levels of 71 pathway-specific genes in whole blood were measured. The data was subjected to principal component analysis (PCA), fifty-fifty MANOVA, ANOVA, and partial least square regression (PLSR).

RESULTS

PCA of pStat levels clustered patients according to NAb class independently of time. PCA of gene expression data clustered patients according to NAb class but was affected by time and treatment. In the fifty-fifty MANOVA, NAb class was significant for both pStat levels and gene expression data. The ANOVA identified pStat1 protein in several cell subtypes as significantly affected by NAb class. The best fitting model for NAb prediction based on PLSR included pStat1 in monocytes, T cells, or lymphocytes and pStat3 in monocytes (r = 0.97). Gene expression data were slightly less predictive of NAb titers.

CONCLUSION

Based on this proof of concept study, we hypothesize that NAb effects can be monitored by evaluation of a single biomarker, pStat1, in either monocytes or T cells by phosphoflow directly after IFN-β administration. The method will significantly reduce cost relative to labor intensive in vitro methods and offers a patient-specific approach to NAb evaluation.

Treatment options for patients with multiple sclerosis who have a suboptimal response to interferon-β therapy

BACKGROUND AND PURPOSE

Although the first-line disease-modifying therapies (DMTs) interferon beta and glatiramer acetate have a favourable benefit-to-risk profile, they are only partially effective for treating relapsing-remitting multiple sclerosis (RRMS). The optimization of treatment in patients who do not show a maximum response to first-line therapy is critical for achieving the best long-term outcomes. Treatment strategies for patients with a suboptimal response include switching to another first-line DMT or a second-line DMT. Natalizumab and fingolimod are approved for RRMS with high disease activity in the European Union and Canada.

METHODS

A comprehensive literature search for articles published between 1990 and April 2012 was undertaken.

RESULTS

This review discusses key clinical and safety data for fingolimod and natalizumab, particularly in the patient subgroups for whom these treatments are approved. Benefit-to-risk profiles, including first-dose cardiovascular effects associated with fingolimod and the risk of progressive multifocal encephalopathy with natalizumab, are discussed.

CONCLUSION

A descriptive comparison of fingolimod and natalizumab is provided in the context of the decision-making process of how and when to switch patients who have a suboptimal response to first-line therapy.

Early detection of neutralizing antibodies to interferon-beta in multiple sclerosis patients: binding antibodies predict neutralizing antibody development

BACKGROUND

Neutralizing antibodies (NAb) affect efficacy of interferon-beta (IFN-b) treatment in multiple sclerosis (MS) patients. NAbs evolve in up to 44% of treated patients, usually between 6-18 months on therapy.

OBJECTIVES

To investigate whether early binding antibody (BAb) titers or different IFN-b biomarkers predict NAb evolution.

METHODS

We included patients with MS or clinically isolated syndrome (CIS) receiving de novo IFN-b treatment in this prospective European multicenter study. Blood samples were collected at baseline, before and after the first IFN-b administration, and again after 3, 12 and 24 months on that therapy; for determination of NAbs, BAbs, gene expression of MxA and protein concentrations of MMP-9, TIMP-1, sTRAIL, CXCL-10 and CCL-2.

RESULTS

We found that 22 of 164 (13.4%) patients developed NAbs during a median time of 23.8 months on IFN-b treatment. Of these patients, 78.9% were BAb-positive after 3 months. BAb titers ≥ 1:2400 predicted NAb evolution with a sensitivity of 74.7% and a specificity of 98.5%. Cross-sectionally, MxA levels were significantly diminished in the BAb/NAb-positive samples; similarly, CXCL-10 and sTRAIL concentrations in BAb/NAb-positive and BAb-positive/NAb-negative samples, respectively, were also diminished compared to BAb/NAb-negative samples.

CONCLUSIONS

BAb titers reliably predict NAbs. CXCL-10 is a promising sensitive biomarker for IFN-b response and its abrogation by anti-IFN-b antibodies.

Use of a standardized MxA protein measurement-based assay for validation of assays for the assessment of neutralizing antibodies against interferon-β

Effective monitoring of the development of neutralizing antibodies (NAbs) against IFN-β in multiple sclerosis (MS) patients on IFN-β therapy is important for clinical decision making and disease management. To date, antiviral assays have been the favored approach for NAb determination, but variations in assay conditions between laboratories and the increasing use of novel assays have contributed to the reporting of inconsistent antibody data between laboratories and between products. This study, undertaken at the request of the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA), is a joint effort by manufacturers of IFN-β products (approved in Europe) towards harmonization of a NAb assay that facilitates generation of comparable NAb data, which, in conjunction with clinical outcomes, should prove useful for clinicians treating MS patients with IFN-β products. This article describes the standardized cellular myxovirus resistance protein A (MxA) protein measurement-based assay for detection of IFN-β NAbs and its use for the validation of assays used for the quantitative determination of such antibodies. Although titers varied between laboratories and the products used, utilization of IFN-β1a rather than IFN-β1b as the challenge antigen produced more consistent results in the NAb assay. Adoption of the standardized assay improves comparability between laboratories circumventing problems that arise when different, nonstandardized assays are employed for immunogenicity assessment. Based on the data, the EMA recommended for standardization purposes, the use of IFN-β1a in NAb assays, independent of the therapeutic product used for therapy and validation of new NAb procedures against the standardized assay described.

Consensus guidelines for the diagnosis and treatment of multiple sclerosis

The diagnosis of multiple sclerosis (MS) is dependent on the presence of clinical and paraclinical evidence demonstrating dissemination of central nervous system lesions in both space and time, as well as the exclusion of other disorders. Diagnostic criteria were originally promulgated in 1965 by the Schumacher committee and modified subsequently by the Poser committee to include paraclinical evidence. The most recent criteria are the 2010 modifications of the 2001 McDonald criteria, which are focused on making an earlier diagnosis of MS. This article provides guidelines, derived from clinical experience as well as evidence-based medicine, for the diagnosis and management of MS with special emphasis on practices in the Middle East.

Personalized medicine in multiple sclerosis: hope or reality?

Personalized treatment is highly desirable in multiple sclerosis because it is an immensely heterogeneous disease. This heterogeneity is seen in both the disease course and the treatment responses. Currently, a combination of clinical features and imaging parameters in magnetic resonance imaging is used to classify active and non-active patients and treatment responders and non-responders. Although this classification works on a group level, individual patients often behave differently from the group. Therefore additional biomarkers are needed to provide better indicators for prognosis and treatment response. Basic and clinical research have discovered different promising targets. It is now essential to verify the utility and accuracy of these markers in large, prospectively sampled patient cohorts.

Prevalence of anti-drug antibodies against interferon beta has decreased since routine analysis of neutralizing antibodies became clinical practice

BACKGROUND

Neutralizing antibodies (NAbs) against interferon beta (IFNβ) lead to loss of treatment efficacy in multiple sclerosis patients. The seroprevalence of NAbs in multiple sclerosis patients treated with IFNβ during 2003-2004 was 32% in a cross-sectional analysis of routine data.

OBJECTIVES

The aim of this study was to investigate whether the seroprevalence of NAbs, the levels of NAb titres and the IFNβ preparations used for treatment of multiple sclerosis patients had changed in 2009-2010.

METHODS

This study included 1296 patients, analysed for NAbs with the myxovirus resistance protein A gene expression assay in 2009-2010.

RESULTS

The seroprevalence of NAbs had decreased to 19% in 2009-2010, which is significantly lower compared with the previous study in 2003-2004 (p<0.0001). This decrease was attributed to the IFNβ-1a preparations only, not to IFNβ-1b. The frequency of patients with high positive titres decreased the most, from 16% to 7% (p<0.0001).

CONCLUSIONS

NAb seroprevalence has decreased since NAb monitoring became clinical practice in 2003, especially for patients with high NAb titres. This might be due to the stricter monitoring of NAb titres that prompt NAb positive patients to stop treatment, to preferential use of less immunogenic drugs and to alteration of drug formulations.

Immunogenic effects of recombinant interferon-beta therapy disrupt the JAK/STAT pathway in primary immune cells from patients with multiple sclerosis

BACKGROUND

Immunogenicity of recombinant interferon-β (IFN-β) is a known complication in the therapy of relapsing-remitting multiple sclerosis (RRMS). Neutralizing antibodies (NAbs) that can interfere with efficacy are quantified using in vitro bioassays; however, these assays do not reveal the immunogenic state of the patient and are not predictive of treatment outcome.

OBJECTIVE

Assessment of the impact of NAbs on IFN-β responsive cells and signalling pathways in peripheral blood mononuclear cells (PBMCs) with phospho-specific flow cytometry.

METHOD

PBMCs from 10 IFN-β-treated patients with RRMS, two untreated patients, and two healthy controls were re-stimulated in autologous sera and media with a serial dilution of IFN-β (0-8000 U/ml) and levels of phosphorylation of STAT1/3/4/5/6 transcription factors were quantified in PBMC subtypes (NAb titres 0 to > 6000 neutralizing units). Data was subjected to principal component analysis, Hotelling's T (2), and partial least squares analysis.

RESULTS

Three significantly distinct clusters of individuals were revealed in autologous sera: therapy-naïve and healthy, treated NAb-negative, and treated NAb-positive. Compared with controls STATs signalling patterns were modulated in treated NAb-negative patients and inhibited in all treated NAb-positive patients independently of NAb titres. In media no clustering of patients could be found. The predictability of NAb titres based on the phospho-flow data was 74%.

CONCLUSION

Phospho-specific flow cytometry can delineate subset-specific cell responses that can act as surrogates for NAb exposure in blood. Immunogenic effects alter the response in primary cells even at low NAb levels. Cell line-based immunogenicity testing is not readily transferable to the immunogenic response in patients.

Persistency of neutralizing antibodies depends on titer and interferon-beta preparation

Background: Neutralizing antibodies (NAbs) affect the efficacy of interferon-beta (IFNβ) treatment in multiple sclerosis (MS) patients, particularly if NAbs persist. Persistency depends on NAb titers, which differ between IFNβ preparations.

Objective: This study evaluated IFNβ preparation-specific NAb cut-off titers during early treatment for prediction of NAb persistency.

Methods: Patients who had at least one NAb test between 12 and 30 months (baseline) as well as after more than 48 months (follow-up) on IFNβ treatment were included in this longitudinal study.

Results: At baseline 1064 patients had a NAb test. Of those, 203 had a follow-up test. In the follow-up group 23.2% of patients were NAb positive during baseline. NAb frequency significantly decreased by 40.7% in the IFNβ-1a and by 60% in the IFNβ-1b group at follow-up after a mean time of 75.4 months on treatment, and median NAb titers decreased significantly in both groups. During baseline, NAb titers of >258 neutralizing units (NU) had a sensitivity of 81.3% and a specificity of 90.9% in the IFNβ-1a group, whereas titers of >460 NU had a sensitivity of 100% and a specificity of 91.7% in the IFNβ-1b group to predict persistency at follow-up. When these cut-off titers are applied, 10.2% of all treated patients developed persistent NAbs.

Conclusion: IFNβ preparation-specific NAb cut-off titers for prediction of NAb persistency, which may be useful in individual treatment decision making, are provided.

Serum from interferon-β-1b-treated patients with early multiple sclerosis stabilizes the blood-brain barrier in vitro

Interferon-β (IFN-β) stabilizes the blood-brain barrier (BBB) in vitro. Here we investigated the effect of serum from 15 IFN-β-1b-treated multiple sclerosis (MS) patients on the permeability read-outs of small solutes in an in vitro BBB model consisting of human brain microvascular endothelial cells in co-culture with rat astrocytes. The addition of sera from IFN-β-treated patients resulted in a significantly (p < 0.05) reduced permeability as compared with untreated patients. Our findings show that sera from IFN-β-1b-treated MS patients have a stabilizing effect on the in vitro BBB. We suggest an unknown potentially pro-inflammatory factor in the serum of MS patients that may lead to a BBB dysfunction and can be modulated by IFN-β.

Single-nucleotide polymorphisms in HLA- and non-HLA genes associated with the development of antibodies to interferon-β therapy in multiple sclerosis patients

Interferons-β (IFN-β) are the most widely used immunomodulatory drugs for treatment of multiple sclerosis (MS). The development of neutralizing antibodies (NABs) against IFN-β is one of the main reasons for treatment failure. While formulation of the drug has a proven impact on the development of NABs, the genetic predisposition to develop antibodies is poorly understood. We performed genome-wide single-nucleotide polymorphism (SNP) genotyping in 362 MS patients of whom 178 had developed and 184 had not developed antibodies on IFN-β therapy. Four candidate SNPs were validated in an independent cohort of 350 antibody-positive and 468 antibody-negative MS patients. One SNP within the human leucocyte antigen (HLA) region (rs9272105, P-value: 3.56 × 10⁻¹⁰) and one SNP in an intergenic region on chromosome 8q24.3 (rs4961252, P-value: 2.92 × 10⁻⁸ showed a genome-wide significant association with the anti-IFN-β antibody titers. We found no interaction between the genome-wide significant SNPs (rs9272105 and rs4961252) in our study and the previously described HLA-DR*0401 or *0408 alleles, indicating an additive effect of SNPs and HLA alleles. Testing for these SNPs and the HLA-DR*0401 or *0408 alleles allows to identify patients at risk to develop antibodies to IFN-β and may provide helpful information for individual treatment decisions.

Interferon-β-1b: a review of its use in multiple sclerosis

Interferon-β-1b has been used as a disease-modifying therapy in multiple sclerosis (MS) for many years. Although its mechanism of action in MS has not been fully elucidated, it appears to involve immunomodulatory effects mediated by interactions with specific receptors. Large, randomized, multicentre, clinical trials of 2-3.5 years' duration have demonstrated the efficacy of interferon-β-1b 250 μg subcutaneously every other day in patients with a first clinical event suggestive of MS (i.e. those with clinically isolated syndrome [CIS]) and in those with relapsing-remitting MS (RRMS). In terms of its efficacy on primary (or co-primary) endpoints, interferon-β-1b significantly reduced the risk of developing clinically definite MS compared with placebo in patients with CIS in the BENEFIT study. In patients with RRMS, interferon-β-1b was associated with a significantly lower annualized relapse rate and a significantly higher proportion of relapse-free patients compared with placebo in a registration trial conducted by the Interferon-β MS Study Group. The INCOMIN trial in patients with RRMS showed a significant advantage of interferon-β-1b over intramuscular interferon-β-1a in terms of the percentage of relapse- and progression-free patients and the proportion of patients without new MRI-documented lesions. Other active-comparator trials in RRMS used a variety of primary (or co-primary) endpoints and showed no significant differences between interferon-β-1b and either subcutaneous glatiramer acetate (BECOME and BEYOND trials) or subcutaneous interferon-β-1a (Danish MS Group trial) for these outcomes. In patients with secondary progressive MS (SPMS), the European Study Group showed that interferon-β-1b significantly increased the time to confirmed disease progression compared with placebo, although there was no significant between-group difference for this primary endpoint in a similar trial conducted by the North American Study Group. The studies allowed inclusion of patients with superimposed relapse, and both trials showed a significant reduction in annualized relapse rate with interferon-β-1b. The most frequently reported adverse events with interferon-β-1b are flu-like symptoms and injection-site reactions, which can usually be managed. The incidence of these adverse events generally declines markedly after the first year of treatment. Lymphopenia is the most frequently reported laboratory abnormality and occurs in the majority of patients. Depression, suicidal ideation and injection-site necrosis were the most serious adverse events reported with interferon-β-1b in clinical trials. Long-term safety data over a 16-year follow-up period showed no unexpected adverse events among patients treated with interferon-β-1b. Thus, interferon-β-1b is a well established, first-line, disease-modifying therapy that has demonstrated efficacy in newly emerging MS, RRMS and SPMS with superimposed relapse in well designed clinical trials, and has a generally manageable tolerability profile, with no unexpected adverse events after many years of follow-up.

An assessment of biological potency and molecular characteristics of different innovator and noninnovator interferon-beta products

Approved innovator products and their noninnovator "copy" versions are likely to vary in their quality, eg, physicochemical characteristics and biological activity, with important implications for clinical efficacy and safety. Therefore, it is important to study and thoroughly evaluate the noninnovator products in comparison with approved products at the preclinical and clinical stages. We have obtained 4 noninnovator interferon (IFN)-β-1a products currently marketed in Latin America and Iran and compared these with approved IFN-β-1a products (Avonex and Rebif) obtained from the same geographical regions with respect to biological potency, estimated by in vitro bioassays, and molecular characteristics, assessed by immunoblotting and high-performance liquid chromatography. In this article, we present our data showing that the noninnovator IFN-β-1a products can vary considerably in their biological potency. In addition, we showed that all IFN-β-1a products formulated with human serum albumin contained variable amounts of higher-molecular-weight aggregates of IFN-β-1a and adducts with human serum albumin, these being more prevalent in 2 noninnovator IFN-β-1a products where biological potency was reduced compared with approved IFN-β-1a products. Additionally, significant lot-to-lot variability was observed for one of the noninnovator products. Taken together, the results of this study highlight the need for not only thorough in vitro characterization, but also preclinical and clinical assessment to ensure patient safety and efficacy.

Natalizumab treatment reduces endothelial activity in MS patients

Vascular cell adhesion molecule-1 a ligand for leukocyte very late activating antigen-4 is a key player in leukocyte extravasation in MS lesions. Natalizumab a monoclonal antibody against VLA-4 blocks this interaction. VCAM-1 and its soluble form are up-regulated during endothelial activation in MS. We investigated the effect of Natalizumab on sVCAM-1 and VLA-4 on circulating leukocytes in MS patients. Natalizumab reduced levels of sVCAM-1 compared to controls (256 vs. 597 ng/mL). This effect was sustained and only reversed in patients with neutralizing antibodies against Natalizumab. Correspondingly Natalizumab diminished VLA-4 on leukocyte subsets. Our findings indicate that Natalizumab reduces transmigration not only by blocking VLA-4 but also by down-regulating VCAM-1.

Recommendations for clinical use of data on neutralising antibodies to interferon-beta therapy in multiple sclerosis

The identification of factors that can affect the efficacy of immunomodulatory drugs in relapsing-remitting multiple sclerosis (MS) is important. For the available interferon-beta products, neutralising antibodies (NAb) have been shown to affect treatment efficacy. In June, 2009, a panel of experts in MS and NAbs to interferon-beta therapy convened in Amsterdam, Netherlands, under the auspices of the Neutralizing Antibodies on Interferon beta in Multiple Sclerosis consortium, a European-based project of the 6th Framework Programme of the European Commission, to review and discuss data on NAbs and their practical consequences for the treatment of patients with MS on interferon beta. The panel believed that information about NAbs and other markers of biological activity of interferons (ie, myxovirus resistance protein A [MxA]) can be integrated with clinical and imaging indicators to guide individual treatment decisions. In cases of sustained high-titre NAb positivity and/or lack of MxA bioactivity, a switch to a non-interferon-beta therapy should be considered. In patients who are doing poorly clinically, therapy should be switched irrespective of NAb or MxA bioactivity.

Differential response to treatment of relapsing–remitting multiple sclerosis with IFN-β: is there a dichotomy into T-helper-1 and -17 driven disease?

Evaluation of: Axtell RC, de Jong BA, Boniface K et al.: T helper type 1 and type 17 cells determine efficacy of interferon-β in multiple sclerosis and experimental encephalomyelitis. Nat. Med. 16, 406–412 (2010). This study aimed to assess the mechanism of action of IFN-β in the treatment of relapsing–remitting multiple sclerosis (MS). It shows that IFN-β leads to amelioration of experimental autoimmune encephalomyelitis, the animal model of MS, if disease is induced with T-helper (Th)1 cells. In this case, response to therapy requires the presence of IFN-γ, and IL-10-secreting cells are induced. By contrast, in experimental autoimmune encephalomyelitis induced with Th17 cells, treatment with IFN-β leads to an aggravation of the condition. Patients with relapsing–remitting MS were subsequently stratified into responder (n = 12) and nonresponders (n = 14) to IFN-β treatment. In nonresponder patients, high pretreatment levels of IL-17F and endogenous IFN-β were present. These findings lead to the conclusion that there might be a dichotomy of disease biology of relapsing–remitting MS: MS patients with a Th1-biased disease respond to IFN-β, while patients with a Th17-biased disease do not. The study contains a number of interesting observations; however, further studies with larger numbers of patients are necessary to evaluate and possibly confirm the findings.