Interferon beta preparations for the treatment of multiple sclerosis patients differ in neutralizing antibody seroprevalence and immunogenicity

Longitudinal analysis of anti-drug antibody development in multiple sclerosis patients treated with interferon beta-1a (Rebif™) using B cell receptor repertoire analysis

A significant proportion of multiple sclerosis (MS) patients treated with interferon beta-1a (Rebif™) develop anti-drug antibodies (ADA) with a negative impact on treatment efficacy. We hypothesized that high-throughput B-cell receptor (BCR) repertoire analysis could be used to predict and monitor ADA development. To study this we analyzed 228 peripheral blood samples from 68 longitudinally followed patients starting on interferon beta-1a. Our results show that whole blood BCR analysis does not reflect, and does not predict ADA development in MS patients treated with interferon beta-1a. We propose that BCR analysis of phenotypically selected cell subsets or tissues might be more informative.

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.

Multiple Sclerosis: Therapeutic Strategies on the Horizon

Multiple sclerosis (MS) is a chronic disease affecting the brain and the spinal cord. It is a chronic inflammatory demyelinating disease of the central nervous system. It is the leading cause of non-traumatic disability in young adults. The clinical course of the disease is quite variable, ranging from stable chronic disease to rapidly evolving debilitating disease. The pathogenesis of MS is not fully understood. Still, there has been a rapid shift in understanding the immune pathology of MS away from pure T cell-mediated disease to B cells and microglia/astrocytes having a vital role in the pathogenesis of MS. This has helped in the emergence of new therapies for management. Effective treatment of MS requires a multidisciplinary approach to manage acute attacks, prevent relapses and disease progression and treat the disabling symptoms associated with the disease. In this review, we discuss the pathogenesis of MS, management of acute relapses, disease-modifying therapies in MS, new drugs and drugs currently in trial for MS and the symptomatic treatment of MS.  All language search was conducted on Google Scholar, PubMed, MEDLINE, and Embase till February 2022. The following search strings and medical subheadings (MeSH) were used: "Multiple Sclerosis", "Pathogenesis of MS", and "Disease-modifying therapies in MS". We explored literature on the pathogenic mechanisms behind MS, management of acute relapses, disease-modifying therapies in MS and symptomatic management.

Long-Term Consequences of High Titer Neutralizing Antibodies to Interferon-β in Multiple Sclerosis

Background

Neutralizing anti-drug antibodies (NAbs) to interferon beta (IFNβ) develop in up to 47% of multiple sclerosis (MS) treated patients inhibiting treatment effect of IFNβ. However, the long-term effect of NAbs remain unknown.

Objective

To investigate the long-term consequences of high titer NAbs to IFNβ on disease activity and progression in MS patients.

Methods

An observational study including data from all IFNβ treated relapsing remitting MS patients with sufficient NAb test results from the Swedish MS registry. Patients were classified into either confirmed ‘high titer’ or ‘persistent negative’ groups and analyzed for differences in disease activity and progression over time.

Results

A total of 197 high-titer and 2907 persistent negative patients with 19969.6 follow up years of data were included. High titer NAbs were associated with a higher degree of disease activity at baseline. However, even when accounting for this, the presence of high titer NAbs were also associated with higher disease activity during IFNβ treatment. This persisted even after the next DMT start, suggesting that earlier high titers may partially reduce the effect of later treatments. No difference was found in confirmed disability progression.

Conclusion

High titer NAbs to IFNβ are associated with higher disease activity, persisting even after IFNβ discontinuation or switch. These results support use of highly efficient treatment earlier in patients with active disease, to avoid these complications.

Monocyte NOTCH2 expression predicts IFN-β immunogenicity in multiple sclerosis patients

Multiple sclerosis (MS) is an autoimmune disease characterized by CNS inflammation leading to demyelination and axonal damage. IFN-β is an established treatment for MS; however, up to 30% of IFN-β-treated MS patients develop neutralizing antidrug antibodies (nADA), leading to reduced drug bioactivity and efficacy. Mechanisms driving antidrug immunogenicity remain uncertain, and reliable biomarkers to predict immunogenicity development are lacking. Using high-throughput flow cytometry, NOTCH2 expression on CD14+ monocytes and increased frequency of proinflammatory monocyte subsets were identified as baseline predictors of nADA development in MS patients treated with IFN-β. The association of this monocyte profile with nADA development was validated in 2 independent cross-sectional MS patient cohorts and a prospective cohort followed before and after IFN-β administration. Reduced monocyte NOTCH2 expression in nADA+ MS patients was associated with NOTCH2 activation measured by increased expression of Notch-responsive genes, polarization of monocytes toward a nonclassical phenotype, and increased proinflammatory IL-6 production. NOTCH2 activation was T cell dependent and was only triggered in the presence of serum from nADA+ patients. Thus, nADA development was driven by a proinflammatory environment that triggered activation of the NOTCH2 signaling pathway prior to first IFN-β administration.

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.

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.

Mouse Models for Assessing Protein Immunogenicity: Lessons and Challenges

The success of clinical and commercial therapeutic proteins is rapidly increasing, but their potential immunogenicity is an ongoing concern. Most of the studies that have been conducted over the past few years to examine the importance of various product-related attributes (in particular several types of aggregates and particles) and treatment regimen (such as dose, dosing schedule, and route of administration) in the development of unwanted immune responses have utilized one of a variety of mouse models. In this review, we discuss the utility and drawbacks of different mouse models that have been used for this purpose. Moreover, we summarize the lessons these models have taught us and some of the challenges they present. Finally, we provide recommendations for future research utilizing mouse models to improve our understanding of critical factors that may contribute to protein immunogenicity.

Baseline MxA mRNA expression predicts interferon beta response in multiple sclerosis patients

BACKGROUND

Myxovirus resistance protein A (MxA) is a molecule induced after interferon-beta injection, mostly used to evaluate its bioactivity. There is little available data on clinical utility of baseline MxA mRNA status. The objective of the study is to investigate whether baseline MxA mRNA expression can predict relapse and disease progression in multiple sclerosis patients treated with interferon-beta.

METHODS

Baseline blood samples were obtained before the first interferon-beta dose was administered to evaluate MxA mRNA expression using real-time polymerase chain reaction (PCR). Demographic and clinical variables were prospectively recorded to define treatment responder and non responder groups.

RESULTS

104 patients were included in the study. Baseline MxA mRNA expression was significantly lower in the group of patients who met the definition of responders (1.07 vs 1.95, Student t test, p<0.0001). A threshold of 1.096 was established using Receiver Operating Characteristic analysis to differentiate between responders and non-responders (sensitivity 73.9%, specificity 69.0%). Survival analysis using this threshold showed that time to next relapse (p<0.0001) and to EDSS progression (p = 0.01) were significantly higher in patients with lower MxA titers.

CONCLUSION

The results suggest that baseline MxA mRNA levels may be useful for predicting whether multiple sclerosis patients will respond or not to interferon-beta treatment.

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.

Human leukocyte antigen genes and interferon beta preparations influence risk of developing neutralizing anti-drug antibodies in multiple sclerosis

A significant proportion of patients with multiple sclerosis who receive interferon beta (IFNβ) therapy develop neutralizing antibodies (NAbs) that reduce drug efficacy. To investigate if HLA class I and II alleles are associated with development of NAbs against IFNβ we analyzed whether NAb status and development of NAb titers high enough to be biologically relevant (>150 tenfold reduction units/ml) correlated with the HLA allele group carriage in a cohort of 903 Swedish patients with multiple sclerosis treated with either intramuscular IFNβ-1a, subcutaneous IFNβ-1a or subcutaneous IFNβ-1b. Carriage of HLA-DRB1*15 was associated with increased risk of developing NAbs and high NAb titers. After stratification based on type of IFNβ preparation, HLA-DRB1*15 carriage was observed to increase the risk of developing NAbs as well as high NAb titers against both subcutaneous and intramuscular IFNβ-1a. Furthermore, in patients receiving subcutaneous IFNβ-1a carriage of HLA-DQA1*05 decreased the risk for high NAb titers. In IFNβ-1b treated patients, HLA-DRB1*04 increased the risk of developing high NAb titers, and in a subgroup analysis of DRB1*04 alleles the risk for NAbs was increased in DRB1*04:01 carriers. In conclusion, there is a preparation-specific genetically determined risk to develop NAbs against IFNβ high enough to be clinically relevant in treatment decisions for patients with multiple sclerosis if confirmed in future studies. However, choice of IFNβ preparation still remains the single most significant determinant for the risk of developing NAbs.

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.

Anti-interferon beta antibody titers strongly correlate between two bioassays and in vivo biomarker expression, and indicates that a titer of 150 TRU/mL is a biologically functional cut-point

Interferon beta (IFNβ) is used as a first-line treatment in relapsing-remitting multiple sclerosis (MS). The occurrence of neutralizing antidrug antibodies (NAbs) against IFNβ may reduce treatment response. Therefore, clinical monitoring of NAbs is currently executed using bioassays, but several bioassays are available and it is unclear how well their readouts correlate. We made a comparison between 2 bioassays; myxovirus resistance protein A (MxA) gene expression assay (MGA) and iLite™ anti-Human IFNβ bioassay, to measure IFNβ-specific NAb titers in 44 MS patients. We further studied how NAb titers affected in vivo transcription of IFN-induced genes myxovirus resistant 1 (MX1) and C-X-C motif chemokine 10 (CXCL10), in addition to serum CXCL10 protein levels. There were significant correlations between NAb titer levels measured with MGA and iLite (Spearman r=0.9368). MX1 and CXCL10 gene expression was strongly induced by IFNβ and NAb positivity significantly reduced this expression. A NAb titer of 150 TRU/mL was observed to be a biological cut-point applicable to both assays, since MX1 and CXCL10 expression was greatly reduced or blocked in patients above this titer level. In conclusion, NAb titers measured with the MGA and iLite bioassays are comparable, but the threshold for positivity in both assays does not correspond to the biologically functional cut-point.

Antibodies to interferon beta in patients with multiple sclerosis receiving CinnoVex, rebif, and betaferon

Treatment with interferon beta (IFN-β) induces the production of binding antibodies (BAbs) and neutralizing antibodies (NAbs) in patients with multiple sclerosis (MS). NAbs against IFN-β are associated with a loss of IFN-β bioactivity and decreased clinical efficacy of the drug. The objective of this study was to evaluate the incidence and the prevalence of binding antibodies (BAbs) and neutralizing antibodies (NAbs) to IFN-β in MS patients receiving CinnoVex, Rebif, or Betaferon. The presence of BAbs was studied in serum samples from 124 MS patients using one of these IFN-β medications by ELISA. The NAbs against IFN-β were measured in BAb-positive MS patients receiving IFN-β using an MxA gene expression assay (real-time RT-PCR). Of the 124 patients, 36 (29.03%) had BAbs after at least 12 months of IFN-β treatment. The proportion of BAb+ was 38.1% for Betaferon, 21.9% for Rebif, and 26.8% for CinnoVex. Five BAb-positive MS patients were lost to follow-up; thus 31 BAb-positive MS patients were studied for NAbs. NAbs were present in 25 (80.6%) of BAb-positive MS patients receiving IFN-β. In conclusion, the three IFN-β preparations have different degrees of immunogenicity.

Smoking and risk of treatment-induced neutralizing antibodies to interferon β-1a

BACKGROUND

Neutralizing antibodies (NAbs) to interferon β (IFNβ) products that develop during treatment are associated with a loss of clinical efficacy.

OBJECTIVES

The aim of this study was to investigate the influence of smoking habits on the risk of developing NAbs to IFNβ, in the treatment of multiple sclerosis (MS).

METHODS

This report is based on 695 MS patients treated with IFNβ-1a, included in two Swedish case-control studies that collected information on smoking habits. Using logistic regression, the development of NAbs to IFNβ-1a among current smokers was compared with that of non-smokers, by calculating the odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

Current smokers showed an increased risk of developing NAbs to IFNβ-1a, compared with non-smokers (OR 1.9; 95% CI 1.3-2.8; p = 0.002). There were no gender differences. We observed no association between past smoking and the risk of developing NAbs to IFNβ-1a.

CONCLUSIONS

The finding that current smokers have an increased risk of developing NAbs to IFNβ-1a has implications, both for the practical care and the treatment of MS; it also provides an interesting perspective of the lungs as an immune-reactive organ, reacting upon irritation.

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.

Improved analytical methods for the detection and quantification of neutralizing antibodies to biopharmaceuticals

Biopharmaceuticals are used extensively for the treatment of a number of chronic debilitating and fatal diseases such as cancer and inflammatory or autoimmune diseases. Although biopharmaceuticals are in general well tolerated, the development of anti-drug antibodies can impair their safety and efficacy. Assessment of immunogenicity is essential for a more effective and rational use of biopharmaceuticals, and is dependent upon the establishment of efficient standardized assays that allow direct comparison of immunogenicity data with clinical outcome. Although regulatory authorities recommend the use of cell-based assays that reflect the mechanism of action of the drug for the detection of neutralizing anti-drug antibodies, conventional cell-based assays are difficult to standardize and often give variable results. A number of strategies have been adopted to improve the performance of cell-based assays, including quantification of drug-induced proteins using either real-time RT-PCR or branched DNA to detect mRNA, or ELISAs to detect protein, bridging assays using immobilized cells and the use of reporter gene assays. The relative merits and limitations of each of these methods is reviewed herein.

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.

Neutralizing antibodies against interferon-Beta

The development of neutralizing antibodies (NAbs) is a major problem in multiple sclerosis (MS) patients treated with interferon-beta (IFN-ß). Whereas binding antibodies (BAbs) can be demonstrated in the vast majority of patients, only a smaller proportion of patients develop NAbs. The principle in NAb in vitro assays is the utilization of cultured cell lines that are responsive to IFN-ß. The cytopathic effect (CPE) assay measures the capacity of NAbs to neutralize IFN- ß's protective effect on cells challenged with virus and the MxA induction assay measures the ability of NAbs to reduce the IFN-ß-induced expression of MxA, either at the mRNA or the protein level. A titer of >20 neutralizing units/ml traditionally defines NAb posi-tivity. NAbs in high titers completely abrogate the in vivo response to IFN-ß, whereas the effect of low and intermediate titers is unpredictable. As clinically important NAbs appear only after 9-18 months IFN- ß0 therapy, short-term studies of two years or less are unsuitable for evaluation of clinical NAb effects. All long-term trials of three years or more concordantly show evidence of a detrimental effect of NAbs on relapses, disease activity on MRI, or on disease progression. Persistent high titers of NAbs indicate an abrogation of the biological response and, hence, absence of therapeutic efficacy, and this observation should lead to a change of therapy. As low and medium titers are ambiguous treatment decisions in patients with low NAb titres should be guided by determination of in vivo mRNA MxA induction and clinical disease activity.

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.

Neutralizing antibodies to interferon beta-1b multiple sclerosis: a clinico-radiographic paradox in the BEYOND trial

BACKGROUND

The frequency and impact of neutralizing antibodies (NAbs) to interferon beta-1b (IFNβ-1b) on clinical and radiographic outcomes is controversial.

OBJECTIVE

To assess NAb impact in the BEYOND study.

METHODS

2244 patients were randomized (2:2:1) to receive IFNβ-1b, either 250 or 500 µg, or glatiramer acetate, 20 mg, and observed for 2-3.5 years. NAb titers were determined every 6 months. A titer ≥20 NU/ml was considered NAb positive. Efficacy was compared between NAb-positive and NAb-negative patients, using comprehensive statistical analyses, taking into account the delayed appearance of NAbs, the time-dependent changes in the relapse rate, spontaneous reversions to NAb-negative status, NAb-titer level, and also adjusting for baseline factors.

RESULTS

In the IFNβ-1b 250 µg group, NAb-positive titers were detected (≥ once) in 319 patients (37.0%); of these, 112 (35.1%) reverted to NAb-negative status. In the IFNβ-1b 500 µg group, 340 patients (40.7%) became NAb-positive and 119 (35.0%) reverted to NAb-negative status. In both IFNβ groups, especially the 250 µg arm, NAb-positive status was not associated with a convincing impact on any clinical outcome measure by any statistical analysis. By contrast, in both IFNβ groups, NAbs were associated with a very consistent deleterious impact on most MRI outcomes.

CONCLUSION

There was a notable dissociation between the impact of NAbs on MRI and clinical outcomes. On MRI measures, the impact was consistent and convincing, whereas on clinical measures a negative impact of NAbs was not found. The basis for this clinico-radiographic paradox is unknown but it suggests that the relationship between NAbs and the therapeutic effects of IFNβ-1b is complex.

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.

On the role of aggregates in the immunogenicity of recombinant human interferon beta in patients with multiple sclerosis

Like many other therapeutic proteins, recombinant human interferon beta (rhIFN-&#x03B2;) elicits undesirable immune responses. rhIFN-&#x03B2;-treated multiple sclerosis patients may form binding antibodies and neutralizing antibodies (NAbs), with the latter being responsible for inhibition of the therapeutic effect of the protein. The incidence of binding antibodies and NAbs against rhIFN-&#x03B2; as well as the titer and persistence of NAbs differ among the marketed products. The proportion of patients forming antibodies against rhIFN-&#x03B2;-1b is higher than that against rhIFN-&#x03B2;-1a, which is likely explained by the differences in protein structure and aggregation behavior between the 2 types of rhIFN-&#x03B2;. Here, we summarize the different factors influencing the immunogenicity of rhIFN-&#x03B2; in patients with multiple sclerosis and discuss the role played by rhIFN-&#x03B2; aggregates.

Frequency and magnitude of interferon β neutralizing antibodies in the evaluation of interferon β immunogenicity in patients with multiple sclerosis

Patients with multiple sclerosis (MS) treated with interferon β (IFNβ) preparations develop varying levels of antibodies that neutralize the biological effects of IFNβ, reduce its in vivo bioavailability, and diminish its therapeutic efficacy. The aim was to determine as distinct measures of immunogenicity the occurrence (frequency) and the magnitude (level) of IFNβ neutralizing antibody (NAb) formation in a large Canadian population as a cross-sectional study of patients with MS treated in a clinical practice setting with different, equally available IFNβ products: Avonex(®) (intramuscular IFNβ-1a), Rebif(®) (subcutaneous (SC) IFNβ-1a) at 22 and 44 μg, and Betaseron(®) (SC IFNβ-1b). Over a 3-year period 3,124 serum samples from 2,711 patients with MS were submitted by neurologists in MS clinics distributed across Canada and tested for NAbs in a single independent laboratory, utilizing a quantitative, standardized NAb bioassay. NAb frequency was greatest (35%) with Rebif (SC IFNβ-1a) 44 μg and least (7.5%) with Avonex (intramuscular IFNβ-1a), whereas Betaseron (IFNβ-1b) and Rebif 22 μg were in between (22%). NAb serum levels at magnitudes considered high, ≥100 tenfold reduction units (TRU)/mL, were found in 65%-83% of patients with detectable NAbs. Nearly half (42%-47%) of NAb-positive patients given IFNβ-1a preparations had very high titers (≥ 1,000 TRU/mL), whereas only 22% of NAb-positive patients on Betaseron had titers >1,000 TRU/mL. Differences in patterns of NAb formation among the four IFNβ product-dose combinations became more evident in patients with MS when both NAb frequency and the full range of NAb titer magnitude were measured.

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.

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.

Multiple sclerosis patients lacking oligoclonal bands in the cerebrospinal fluid are less likely to develop neutralizing antibodies against interferon beta

Multiple sclerosis patients without cerebrospinal fluid oligoclonal IgG bands have been proposed to constitute an immunogenetically distinct subgroup of multiple sclerosis that may also differ in terms of prognosis. A proportion of patients with multiple sclerosis receiving IFNbeta develop neutralizing antibodies, which interfere with treatment efficacy. Evidence suggests that the likelihood of developing neutralizing antibodies is partly genetically determined. Here, we hypothesized that absence of oligoclonal IgG bands reflects a property of B-cell responses in oligoclonal IgG band-negative patients characterized by a lessened propensity to develop neutralizing antibodies. We aimed to compare the development of neutralizing antibodies against IFNbeta between oligoclonal IgG band-negative and oligoclonal IgG band-positive multiple sclerosis patients. Treatment, oligoclonal IgG band and neutralizing antibody information was obtained for 2219 patients from the Swedish multiple sclerosis registry and the Swedish neutralizing antibody registry. Additional data on genotype was available for 532 patients. A correlation was found between oligoclonal IgG band negativity and neutralizing antibody negativity (p = 0.02). This difference was confined to neutralizing antibodies against IFNbeta-1a, since oligoclonal IgG band-negative patients were, to a lesser extent, neutralizing antibody positive compared with oligoclonal IgG band-positive patients if treated with IFNbeta-1a (12% vs. 23%; p = 0.005). No difference was observed for IFNbeta-1b-treated patients (44% vs. 46%). We propose that oligoclonal IgG band-negative patients differ immunologically from oligoclonal IgG band-positive patients, potentially influenced by distinct HLA-DRB1 alleles.

PRISMS: the story of a pivotal clinical trial series in multiple sclerosis

BACKGROUND

The PRISMS (Prevention of Relapses and disability by Interferon beta-1a Subcutaneously in Multiple Sclerosis) study was initiated in 1994, at which time there were few disease-modifying drugs for multiple sclerosis (MS). The PRISMS series of studies has since provided up to 8 years of clinical, magnetic resonance imaging (MRI), safety, and immunogenicity data on the use of subcutaneous (sc) interferon (IFN) beta-1a in patients with relapsing-remitting MS. This review is the first collation of all these data in one article, with a look ahead to the next generation of studies involving the new formulation of sc IFN beta-1a.

METHODS

Published efficacy, safety, and immunogenicity data, in terms of prospectively defined endpoints and later post hoc analyses, from years 1-8 of the PRISMS series are summarized and collated for the first time. Some of the studies of sc IFN beta-1a that evolved from the PRISMS studies are also discussed.

FINDINGS

In the 2-year, double-blind, randomized, placebo-controlled study, IFN beta-1a (22 or 44 mcg three times weekly [tiw]) was associated with significantly lower relapse rates, disability progression, and MRI burden of disease compared with placebo (p <or= 0.05). Subsequently, in the 2-year extension, patients previously receiving placebo were re-randomized to active treatment, and a further 2 years of open-label treatment confirmed good long-term safety and therapeutic efficacy. Follow-up visits at years 7 or 8 (68.2% of initial population) demonstrated a continued benefit for patients originally randomized to the 44-mcg dose compared with those receiving the 22-mcg dose or whose treatment had been delayed by 2 years. Neutralizing antibodies were more common in patients receiving the 22-mcg dose and attenuated treatment efficacy during years 1-4.

CONCLUSION

Class I and long-term data from PRISMS support the use of sc IFN beta-1a tiw as a first-line treatment for MS, as evidenced by sustained efficacy rates, acceptable safety profiles, and high patient retention rates.

Biotechnology-Derived Medicines: What are They? A Pharmacological and a Historical Perspective

Biologicals, that is, medicines obtained from living organisms, are not new. History provides many examples of animal or human extracts being used to prevent or treat human diseases. Physicians have thus been aware for centuries of the therapeutic value of our own molecules. The difficulty laid many times in how to obtain these self or self-like compounds. Biotechnology - a technology by which manipulated living organisms are utilized to generate useful products such as drugs - provided a revolutionary answer. We know how to genetically engineer bacteria, yeast, insect or mammalian cells to synthesize human molecules, the so-called human recombinant therapeutic proteins. Murine and humanized monoclonal antibodies against human antigens are also biotechnological products. The number of biotechnological drugs being marketed, and those in clinical trials or awaiting authorization, is growing exponentially. We are now still on the beginnings of a new era in pharmacotherapy of which it is impossible to see the end. Pharmacologists need to keep pace with these changes and develop new skills. They may even have to challenge old assumptions in order to investigate new molecules. Using an easy and comprehensible approach, this review article revisits ‘bio-concepts’, and underlines the real dimension of the challenge.

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.

The clinical effect of neutralizing antibodies against interferon-beta is independent of the type of interferon-beta used for patients with relapsing-remitting multiple sclerosis

Objective

To establish whether the clinical effect of neutralizing antibodies (NAbs) against interferon-beta (IFNβ) depends on the type of IFNβ (1a or 1b) used for treatment of patients with relapsing-remitting multiple sclerosis (MS).

Introduction

NAbs against IFNβ-1b appear faster and may be more evenly distributed on IgG subclasses, whereas NAbs against IFNβ-1a develop more slowly and may be devoid of IgG3. This might cause different clinical responses to NAbs.

Design/patients

All Danish MS-patients who had started first-time treatment with IFNβ-1a 22 μg s.c tiw (Rebif22) or IFNβ-1b 250 μg s.c. qod (Betaferon) before January 1st 2003 were included. Relapses were recorded at bi-annual visit.

Methods

We measured NAbs every 12 months using a clinically validated cytopathic effect assay. A blood sample with a neutralizing capacity of 20% or more was considered as NAb-positive. We used a mixed logistic regression analysis in which NAb-status (three levels), IFNβ-preparation, and time since treatment started were included as explanatory variables, and relapse rate as response variable.

Results

In 1,309 patients, who were observed for 21,958 months, 32.3% were classified as NAb-positive. The odds-ratio (OR) for relapses in NAb-positive months compared with NAb-negative months was 1.25; P = 0.02. The risk of relapses was higher with Betaferon than with Rebif22 (OR 1.26; P < 0.01). The effect of NAb-level on relapses was independent of whether the patients were treated with Betaferon or Rebif22 ( P = 0.89) and of time ( P = 0.80).

Conclusion

NAbs caused by IFNβ-1a s.c. do not differ from NAbs caused by IFNβ-1b in their detrimental clinical effect.

BAFF is a biological response marker to IFN-beta treatment in multiple sclerosis

Multiple sclerosis (MS) is a complex autoimmune disease characterized by the destruction of the myelin sheath of neurons. Interferon beta (IFN-beta) is currently the major drug used to treat MS. Some patients fail to respond to this treatment, in some cases due to the development of neutralizing antibodies (NAb) to IFN-beta. We used microarray analysis and RT-PCR to measure gene expression in whole blood, 9-15 h postinjection, in patients with and without NAbs to IFN-beta. The canonical marker of biological response to IFN-beta, myxovirus resistance protein A, was upregulated in all NAb- patients while remaining unchanged in NAb+ patients. Genes functioning in immune response pathways were dominant in the set of differentially expressed genes: 73 immune response genes were identified as upregulated and 29 genes were identified as downregulated. B-cell activating factor (BAFF) is a strong candidate marker for biological and clinical response as well as for predisposition to NAb development. We demonstrate that it is responsive to IFN-beta in vitro and in vivo, and that its soluble form is elevated in serum from NAb- but not NAb+ patients. We conclude BAFF is a good biomarker for IFN-beta response, and requires further studies to determine its value as a marker for clinical response and NAb predisposition.

Impression of Clinical Worsening Fails to Predict Interferon-β Neutralizing Antibody Status

The development of neutralizing antibodies (NAbs) against interferon-β (IFNβ) reduces clinical efficacy and markers of bioactivity in patients with multiple sclerosis (MS), although it has also been shown that a poor response to IFNβ coincided with unexpectedly low NAb levels. To try and resolve this incoherency, this study investigated 2822 patients referred to a NAb testing facility. The reason for NAb testing was indicated for 2506 patients: routine testing (76%), worsening of disease (14%) and other reasons (10%). Overall, 31% of patients were NAb positive and 17% had titres high enough to obliterate IFNβ bioactivity. The frequency of NAbs was similar in patients in the routine testing group compared with the worsening group. Samples showing high titres failed to be associated with worsening of symptoms. The study failed to show low NAb levels in patients responding poorly to IFNβ. It is concluded that it is not possible to predict NAb status by clinical impression of treatment response. This is likely to be an effect of the partial efficacy of IFNβ. Thus routine testing for NAbs must be carried out in order to identify NAb status in patients with MS.

Safety and immunogenicity of a new formulation of interferon beta-1a (Rebif New Formulation) in a Phase IIIb study in patients with relapsing multiple sclerosis: 96-week results

BACKGROUND

A new formulation of subcutaneous (s.c.) interferon-beta-1a has been developed (Rebif New Formulation, RNF), produced without fetal bovine serum and without human serum albumin as an excipient, with the aim of improving injection tolerability, and reducing immunogenicity.

OBJECTIVES

This article reports 96-week analyses of a Phase IIIb, open-label study of the safety and immunogenicity of RNF compared with historical (EVIDENCE study) and recent (REGARD study) data on the original formulation.

METHODS

Patients with relapsing multiple sclerosis (McDonald criteria) and an Expanded Disability Status Scale score < 6.0 received RNF, 44 microg s.c. three times weekly.

RESULTS

The proportion of neutralizing antibody-positive (NAb+) patients (serum NAb status >or=20 neutralizing units/mL) at week 96 (last observation carried forward; primary endpoint) was 17.4% (exact 95% confidence interval [CI]: 13.0-22.5), compared with 21.4% (95% CI: 17.2-26.2) in the EVIDENCE study, and 27.3% (95% CI: 22.8-32.1) in the REGARD study. The proportion of patients NAb+ at any time during the 96 weeks was 18.9% (95% CI: 14.4-24.2), compared with 27.1% (95% CI: 22.4-32.2) and 33.7% (95% CI: 28.9-38.7), respectively. Most pre-specified categories of adverse events were reported by patients in the RNF study at a similar or lower proportion than in the EVIDENCE and REGARD studies. Injection-site reactions were experienced by fewer patients than in the EVIDENCE and REGARD studies.

CONCLUSIONS

RNF has improved overall immunogenicity and safety profiles compared with the original formulation.