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

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.

Functional neurological disorder: Extending the diagnosis to other disorders, and proposing an alternate disease term—Attentionally-modifiable disorder

BACKGROUND: The term “functional neurological disorder,” or “FND,” applies to disorders whose occurrence of neurological symptoms fluctuate with the patient’s attention to them. However, many other disorders that are not called “FND” nonetheless can also follow this pattern. Consequently, guidelines are unclear for diagnosing “FND.” OBJECTIVE: To review the neurological conditions that follow this pattern, but which have not so far been termed “FND,” to understand their overlap with conditions that have been termed “FND,” and to discuss the rationale for why FND has not been diagnosed for them. METHOD: A systematic review of the PubMed literature registry using the terms “fluctuation,” “inconsistency,” or “attention” did not yield much in the way of these candidate disorders. Consequently, this review instead relied on the author’s personal library of peer-reviewed studies of disorders that have resembled FND but which were not termed this way, due to his longstanding interest in this problem. Consequently, this approach was not systematic and was subjective regarding disease inclusion. RESULTS: This review identified numerous, diverse conditions that generally involve fluctuating neurological symptoms that can vary with the person’s attention to them, but which have not been called “FND.” The literature was unclear for reasons for not referring to “FND” in these instances. CONCLUSION: Most likely because of historical biases, the use of the term “FND” has been unnecessarily restricted. Because at its core FND is an attentionally-influenced disorder that can respond well to behavioral treatments, the field of neurological rehabilitation could benefit by extending the range of conditions that could be considered as “FND” and referred for similar behavioral treatments. Because the term “FND” has been viewed unfavorably by some patients and clinical practitioners and whose treatment is not implied, the alternative term attentionally-modifiable disorder is proposed.

Effect of HLA-DRB1 alleles and genetic variants on the development of neutralizing antibodies to interferon beta in the BEYOND and BENEFIT trials

BACKGROUND

Treatment of multiple sclerosis (MS) with interferon β can lead to the development of antibodies directed against interferon β that interfere with treatment efficacy. Several observational studies have proposed different HLA alleles and genetic variants associated with the development of antibodies against interferon β.

OBJECTIVE

To validate the proposed genetic markers and to identify new markers.

METHODS

Associations of genetic candidate markers with antibody presence and development were examined in a post hoc analysis in 941 patients treated with interferon β-1b in the Betaferon^® Efficacy Yielding Outcomes of a New Dose (BEYOND) and BEtaseron^®/BEtaferon^® in Newly Emerging multiple sclerosis For Initial Treatment (BENEFIT) prospective phase III trials. All patients were treated with interferon β-1b for at least 6 months. In addition, a genome-wide association study was conducted to identify new genetic variants.

RESULTS

We confirmed an increased risk for carriers of HLA-DRB1*04:01 (odds ratio (OR) = 3.3, p = 6.9 × 10^-4) and HLA-DRB1*07:01 (OR = 1.8, p = 3.5 × 10^-3) for developing neutralizing antibodies (NAbs). Several additional, previously proposed HLA alleles and genetic variants showed nominally significant associations. In the exploratory analysis, variants in the HLA region were associated with NAb development at genome-wide significance (OR = 2.6, p = 2.30 × 10^-15).

CONCLUSION

The contribution of HLA alleles and HLA-associated single-nucleotide polymorphisms (SNPs) to the development and titer of antibodies against interferon β was confirmed in the combined analysis of two multi-national, multi-center studies.

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.

Comparative effectiveness of interferons in relapsing-remitting multiple sclerosis: a meta-analysis of real-world studies

BACKGROUND

Differences between interferons have been evaluated for over 20 years. While randomized controlled trial (RCT) data is mainly used for assessments and strong data for causal inferences, it does not necessarily reflect everyday practice. Real-world data may provide additional information.

PURPOSE

To assess the results, quality, and representativeness of observational studies directly comparing interferons (IFNs) in RRMS.

METHODS

Medline and Embase were searched for observational studies comparing IFN-beta-1a 30 mcg IM (Avonex ¹ ), IFN-beta-1a 44 mcg SC (Rebif ² ) and/or IFN-beta-1b 250 mcg SC (Betaseron ³ ). Outcomes included annualized relapse rate (ARR), proportions relapse free, confirmed progression free, treatment persistence, and neutralizing antibodies rates (NABs) measured up to 5 years of treatment. Data was combined using random effects meta-analyses. Categorical values were analyzed using chi-squared and Mann-Whitney tests.

RESULTS

Thirty-six studies examining 32,026 patients (72.5% females, age = 39.2 ± 3.7 years, disease duration = 5.6 ± 2.0 years) were identified. Thirty-three studies investigated IFN-beta-1a IM (N = 11,925), 30 IFN-beta-1a SC (N = 10,684) and 34 IFN-beta-1b SC (N = 9417). Baseline ARRs were similar (1.37 ± 0.35, 1.51 ± 0.27 and 1.55 ± 0.23, respectively; P = .101) as were EDSS scores (2.24 ± 0.39, 2.33 ± 0.30, 2.55 ± 0.38; P = .070) and >75% were naïve to IFNs. On treatment, ARRs were comparable (IFN-beta-1a IM 0.52 ± 0.27, IFN-beta-1a SC 0.51 ± 0.24, IFN-beta-1b SC 0.55 ± 0.23; P = .595). Proportions of relapse-free patients were similar between drugs (P > .05 for all data points), except that IFN-beta-1a SC was superior to IFN-beta-1b SC in years 3-5 (all P ≤ .001). After 1 year, EDSS scores were comparable; after 2 years, IFN-beta-1a IM and IFN-beta-1a SC incurred less disease progression than IFN-beta-1b SC (P < .02). Confirmed progression-free rates and persistence were similar over 5 years. Fewer patients developed NABs with IFN-beta-1a IM (4.7 ± 1.5%) versus IFN-beta-1a SC (21.4 ± 2.8%) (P < 0.001) or IFN-beta-1b SC (32.2% ± 3.3%) (P < .001).

CONCLUSIONS

In this comprehensive meta-analysis of real-world studies in RRMS, IFN-beta-1a IM, IFN-beta-1a SC and IFN-beta-1b SC had similar clinical profiles. When selecting an IFN, practitioners should consider observational data in their decision making process.

Multiple Sclerosis

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

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

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

Interferons-beta versus glatiramer acetate for relapsing-remitting multiple sclerosis

BACKGROUND

Interferons-beta (IFNs-beta) and glatiramer acetate (GA) were the first two disease-modifying therapies (DMTs) approved 20 years ago for the treatment of multiple sclerosis (MS). DMTs' prescription rates as first or switching therapies and their costs have both increased substantially over the past decade. As more DMTs become available, the choice of a specific DMT should reflect the risk/benefit profile, as well as the impact on quality of life. As MS cohorts enrolled in different studies can vary significantly, head-to-head trials are considered the best approach for gaining objective reliable data when two different drugs are compared. The purpose of this systematic review is to summarise available evidence on the comparative effectiveness of IFNs-beta and GA on disease course through the analysis of head-to-head trials.This is an update of the Cochrane review 'Interferons-beta versus glatiramer acetate for relapsing-remitting multiple sclerosis' (first published in the Cochrane Library 2014, Issue 7).

OBJECTIVES

To assess whether IFNs-beta and GA differ in terms of safety and efficacy in the treatment of people with relapsing-remitting (RR) MS.

SEARCH METHODS

We searched the Trials Register of the Cochrane Multiple Sclerosis and Rare Diseases of the CNS Group (08 August 2016) and the reference lists of retrieved articles. We contacted authors and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing directly IFNs-beta versus GA in study participants affected by RRMS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

Six trials were included and five trials contributed to this review with data. A total of 2904 participants were randomly assigned to IFNs (1704) and GA (1200). The treatment duration was three years for one study, two years for the other four RCTs while one study was stopped early (after one year). The IFNs analysed in comparison with GA were IFN-beta 1b 250 mcg (two trials, 933 participants), IFN-beta 1a 44 mcg (three trials, 466 participants) and IFN-beta 1a 30 mcg (two trials, 305 participants). Enrolled participants were affected by active RRMS. All studies were at high risk for attrition bias. Three trials are still ongoing, one of them completed.Both therapies showed similar clinical efficacy at 24 months, given the primary outcome variables (number of participants with relapse (risk ratio (RR) 1.04, 95% confidence interval (CI) 0.87 to 1.24) or progression (RR 1.11, 95% CI 0.91 to 1.35). However at 36 months, evidence from a single study suggests that relapse rates were higher in the group given IFNs than in the GA group (RR 1.40, 95% CI 1.13 to 1.74, P value 0.002).Secondary magnetic resonance imaging (MRI) outcomes analysis showed that effects on new or enlarging T2- or new contrast-enhancing T1 lesions at 24 months were similar (mean difference (MD) -0.15, 95% CI -0.68 to 0.39, and MD -0.14, 95% CI -0.30 to 0.02, respectively). However, the reduction in T2- and T1-weighted lesion volume was significantly greater in the groups given IFNs than in the GA groups (MD -0.58, 95% CI -0.99 to -0.18, P value 0.004, and MD -0.20, 95% CI -0.33 to -0.07, P value 0.003, respectively).The number of participants who dropped out of the study because of adverse events was similar in the two groups (RR 0.95, 95% CI 0.64 to 1.40).The quality of evidence for primary outcomes was judged as moderate for clinical end points, but for safety and some MRI outcomes (number of active T2 lesions), quality was judged as low.

AUTHORS' CONCLUSIONS

The effects of IFNs-beta and GA in the treatment of people with RRMS, including clinical (e.g. people with relapse, risk to progression) and MRI (Gd-enhancing lesions) measures, seem to be similar or to show only small differences. When MRI lesion load accrual is considered, the effect of the two treatments differs, in that IFNs-beta were found to limit the increase in lesion burden as compared with GA. Evidence was insufficient for a comparison of the effects of the two treatments on patient-reported outcomes, such as quality-of-life measures.

Rates of Early Treatment for US Veterans With Multiple Sclerosis

Background: Early treatment of patients with multiple sclerosis (MS) may prevent neurological damage and reduce the risk of disability. However, little is known about the timing of treatment initiation following diagnosis and long-term outcomes in the general population of the Department of Veterans Affairs (VA) benefits-eligible patients. Objective: Our objective was to characterize treatment for MS patients in the VA at various time points following diagnosis date. Methods: In our historical database cohort study of US veterans, we calculated the proportion of MS patients from 1999 through 2010 with at least one prescription for a medication used to treat the condition at 6, 12, 24, 36, 48, 60, and 72 months following the index date. We also stratified the treatments given into 3 categories based on their role within the course of the disease: disease modifying, relapse, and symptom. Finally, we performed our calculations separately by MS subtype: relapsing-remitting, secondary-progressive, primary-progressive, and progressive-relapsing. Results: A total of 6803 patients were included in the analysis. Only 27.4% of MS patients received a prescription for MS medication within the first 6 months after diagnosis. The most common treatments were interferon β-1a, glatiramer, amantadine, and prednisone, with disease-modifying agents being more than twice as frequently prescribed as medications for relapse or symptoms. Patients with relapsing-remitting MS were the most likely to be treated, followed by progressive-relapsing MS. Conclusions: Our results suggest that treatment rates are low in VA MS patients in the 6 years following their first diagnosis of MS.

The role of neutralizing antibodies to interferon-β as a biomarker of persistent MRI activity in multiple sclerosis: a 7-year observational study

PURPOSE

During interferon-β (IFN-β) therapy, up to 45 % of patients may develop neutralizing antibodies (NAbs), associated with a decreased efficacy of the drug. We investigated in a real-life setting the impact of NAbs on magnetic resonance imaging (MRI) outcomes in a population of 567 IFN-β-treated relapsing-remitting (RR) multiple sclerosis (MS) patients up to 7 years. We also evaluated NAbs' role as a biomarker of the persistence of MRI disease activity.

METHODS

Patients' sera were tested for NAbs' presence by cytopathic effect (CPE) assay every 6-12 months. MRI scans were performed every 12 months. Generalized hierarchical linear models accounting for within-patient correlation were used to analyze T1 gadolinium-enhancing and new T2 lesions. Moreover, further tests were carried out to assess the overall outcome difference from year 1 to year 7 according to NAb status and the possible interaction between NAb status and time of follow-up.

RESULTS

Seventy-five patients (13.2 %) became NAb positive (NAb+) during the follow-up. Considering T1 gadolinium-enhancing (GD+) lesions, we observed a significantly higher incidence in NAb+ patients (52 %, p = 0.0091). Also for new T2 lesions, we found a higher incidence in NAb+ patients (50 %, p = 0.0075). The negative impact of NAbs on the MRI outcomes considered did not change during the follow-up.

CONCLUSIONS

Our 7-year results show the negative effect of NAbs on MRI measures of disease activity and confirm their role as a surrogate marker of IFN-β treatment efficacy.

A lesion topography-based approach to predict the outcomes of patients with multiple sclerosis treated with Interferon Beta

BACKGROUND

With increasing availability of effective disease-modifying treatments for multiple sclerosis (MS), an early identification of patients who do not adequately respond to Interferon Beta (IFNB) is relevant to decide the future strategy.

OBJECTIVE

To investigate the predictive role of new lesion location on the risk of breakthrough disease in IFNB-treated patients with MS.

METHODS

We analysed data from 392 patients starting IFNB and regularly followed up to 5 years. Before and after one year of IFNB treatment, all patients underwent a conventional brain and spinal cord magnetic resonancer imaging (MRI) scan with the same 1.5T magnet to obtain the count and location of new MRI lesions. Relapses and MRI activity occurred in the first year of IFNB treatment (year 0-1) were included in the set of potential predictors for relapses and disability worsening in the subsequent four years (year 2-5).

RESULTS

We found that 96 (24.5%) patients had relapses and/or MRI activity in the first year of IFNB treatment, while 41.6% of the patients experienced relapses and 17.8% experienced disability worsening. from year 2 to 5. The risk of relapses (year 2-5) was associated with ≥2 relapses (HR=5.65, p<0.001) and new T2-hyperintense lesions (for 2 new lesions: HR=1.96, p=0.011; for ≥3 new lesions: HR=3.55, p<0.001) in the first year of treatment. Other than male sex (HR=2.01, p=0.01) and higher EDSS score (HR=2.17, p<0.001), the risk of disability worsening (year 2-5) was associated with ≥2 relapses (HR=4.33, p<0.001) and new spinal cord or infratentorial lesions (HR=4.45,p<0.001) in the first year of treatment.

CONCLUSIONS

Our findings suggest a dose-effect relationship between the lesion count and the risk of future relapses, while the occurrence of new MRI lesions in sites representing anatomical bottle-necks was better than lesion count at predicting the future risk of disability worsening despite IFNB treatment.

Development of interferon beta-neutralising antibodies in multiple sclerosis--a systematic review and meta-analysis

PURPOSE

Interferon beta (IFN-β) is the drug of choice for treatment of relapsing forms of multiple sclerosis and is known to reduce the frequency and severity of relapses. This systematic review determines the occurrence of neutralising antibodies (NAbs) against different formulations of IFN-β: IFN-β-1a Avonex™, IFN-β-1a Rebif™ and IFN-β-1b Betaferon/Betaseron™.

METHODS

The databases used in the review included MEDLINE Ovid (from 1950 to March 2015), Embase Ovid (from 1980 to March 2015), CENTRAL on The Cochrane Library (2011, Issue 4) and ClinicalTrials.gov (from 1997 to March 2015). All studies that compared the efficacy of the different formulations of IFN-β in patients with relapsing forms of multiple sclerosis including IFN-β-1a Avonex™, IFN-β-1a Rebif™, IFN-β-1b Betaferon/Betaseron™ and IFN-β-1b Extavia™ were included.

RESULTS

Assessment of randomised controlled trials demonstrated that Avonex™ was 76% less likely than Rebif™ to lead to the formation of NAbs. Avonex™ was 88% less likely than Betaferon/Betaseron™ to lead to the formation of NAbs. Similar findings were also observed in the non-randomised controlled studies, with Avonex™ having the lowest risk. The formation of NAbs was dose dependent: Avonex™ at 30 μg was 64% less risky than Avonex™ at 60 μg.

CONCLUSIONS

Our data show that 2.0-18.9% of patients developed NAbs to Avonex™, 16.5-35.4% of patients developed NAbs to Rebif™ and 27.3-53.3% of patients developed NAbs to Betaferon/Betaseron™.

Predictors of disease activity in 857 patients with MS treated with interferon beta-1b

Multiple sclerosis (MS) is a chronic demyelinating neurodegenerative disease of the CNS that requires long-term treatment. The identification of patient characteristics that can help predict disease outcomes could improve care for patients with MS. The objective of this study is to identify predictors of disease activity in patients from the BEYOND trial. This regression analysis of patients with relapsing–remitting MS from BEYOND examined the predictive value of patient characteristics at baseline and after 1 year of treatment with interferon beta-1b 250 μg every other day for clinical and MRI outcomes after year 1 of the study. 857 and 765 patients were included in the analyses of clinical and MRI outcomes, respectively. In multivariate analyses of age, a higher number of relapses in the past 2 years, ≥3 new MRI lesions in the first year, and, especially, a higher number of relapses in year 1 predicted the future occurrence of relapses. By contrast, age, MRI activity, and the presence of neutralizing antibodies in the first year were principally predictive of future MRI activity. In patients with continued clinical disease activity or substantial MRI activity on therapy, an alternative therapeutic approach should be strongly considered.

Therapeutic Plasma Exchange in Multiple Sclerosis Patients with Abolished Interferon-beta Bioavailability

BACKGROUND

Neutralizing antibodies (NAb) to interferon-beta (IFN-β) are associated with reduced bioactivity and efficacy of IFN-β in multiple sclerosis (MS). The myxovirus resistance protein A (MxA) gene expression is one of the most appropriate markers of biological activity of exogenous IFN-β. We hypothesized that therapeutic plasma exchange (TPE) can restore the ability of IFN-β to induce the MxA mRNA expression and that maintenance plasmapheresis can sustain the bioavailability of IFN-β.

MATERIAL AND METHODS

Eligible patients underwent 4 primary separate plasma exchange sessions. After the induction TPE sessions, they were transferred to maintenance plasmapheresis. Bioactivity of IFN-β was expressed as in vivo MxA mRNA induction in whole blood using RT-qPCR.

RESULTS

Six patients with low IFN-β bioavailability detected by the MxA mRNA response were included. Four patients became biological responders after induction plasmapheresis. In 2 patients an increase of MxA mRNA expression was found, but the values persisted below the cut-off and the patients remained as "poor biological responders". The effect of maintenance plasmapheresis was transient: MxA mRNA expression values reverted to the baseline levels after 1-2 months.

CONCLUSIONS

Therapeutic plasma exchange is able to restore the bioavailability of IFN-β in the majority of studied patients, but the effect of TPE on the IFN-β bioavailability was transient.

Antibody dissociation rates are predictive of neutralizing antibody (NAb) course: a comparison of interferon beta-1b-treated Multiple Sclerosis (MS) patients with transient versus sustained NAbs

A proportion of multiple sclerosis (MS) patients treated with interferon-β (IFNβ) develop neutralizing antibodies (NAbs), which can reduce therapeutic efficacy. In the Betaseron/Betaferon in Newly Emerging MS for Initial Treatment (BENEFIT) study, 88/277 patients developed NAbs, 48 having transient positivity and 29 having sustained positivity. This study aimed to investigate the antibody binding characteristics of serial sera in a subset of these two patient groups. Using Biacore™, a surface plasmon resonance-based technology that monitors biomolecular interactions in real time, we immobilized pure IFNβ-1b and analyzed antibody binding responses and dissociation rates of these sera. NAb titers correlated directly with binding responses and inversely with dissociation rates, and sera from sustained NAb patients demonstrated significantly higher binding responses and slower dissociation rates than sera from transient NAb patients. Thus, transient and sustained NAbs are quantitatively and qualitatively different, and interestingly, binding responses and dissociation rates at month 12 could predict the NAb course.

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.

Current perspectives on interferon Beta-1b for the treatment of multiple sclerosis

Interferon (IFN) beta-1b was the first disease-modifying therapy to be approved for the treatment of multiple sclerosis (MS), and over 21 years of follow-up data demonstrate its efficacy and long-term safety profile. Following recent regulatory approvals in the USA and European Union, IFN beta-1b is now one of the seven disease-modifying therapies [intramuscular IFN beta-1a; subcutaneous (SC) IFN beta-1a; IFN beta-1b SC; glatiramer acetate SC; oral dimethyl fumarate; oral teriflunomide; and intravenous alemtuzumab] indicated for first-line use in relapsing–remitting MS. Here we review the clinical trial and follow-up data for IFN beta-1b and discuss factors that clinicians may consider when selecting this treatment, both at first line in early MS, and later in the disease course.

Interferons-beta versus glatiramer acetate for relapsing-remitting multiple sclerosis

BACKGROUND

Interferons (IFNs)-beta and glatiramer acetate (GA) were the first two disease-modifying therapies (DMTs) approved 15 years ago for the treatment of multiple sclerosis (MS). DMTs prescription rates as first or switching therapies and their costs have increased substantially over the past decade. As more DMTs become available, the choice of a specific DMT should reflect the risk/benefit profile, as well as the impact on quality profile. As MS cohorts enrolled in different studies can vary significantly, head-to-head trials are considered the best approach for gaining objective reliable data when two different drugs are compared. The purpose of this study is to summarise available evidence on the comparative effectiveness of IFNs-beta and GA on disease course through a systematic review of head-to-head trials.

OBJECTIVES

To assess whether IFNs-beta and GA differ in terms of safety and efficacy in the treatment of patients with relapsing-remitting MS (RRMS).

SEARCH METHODS

We searched the Trials Specialised Register of the Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Group (29 October 2013) and the reference lists of retrieved articles. We contacted trialists and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing directly IFNs-beta versus GA in study participants affected by RRMS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by The Cochrane Collaboration.

MAIN RESULTS

Five trials contributed to this review. A total of 2858 participants were randomly assigned to IFNs (1679) and GA (1179). The treatment duration was three years for one study and two years for the other four RCTs. The IFNs analysed in comparison with GA were IFN-beta 1b 250 mcg (two trials, 933 participants), IFN-beta 1a 44 mcg (two trials, 441 participants) and IFN-beta 1a 30 mcg (two trials, 305 participants). Enrolled participants were affected by active RRMS. All studies were at high risk for attrition bias.Both therapies showed similar clinical efficacy at 24 months, given the primary outcome variables (number of participants with relapse (risk ratio (RR) 1.04, 95% confidence interval (CI) 0.87 to 1.24) or progression (RR 1.11, 95% CI 0.91 to 1.35)). However at 36 months, evidence from a single study suggests that relapse rates were higher in the group given IFNs than in the GA group (RR 1.40, 95% CI 1.13 to 1.7, P value 0.002).Secondary magnetic resonance imaging (MRI) outcomes analysis showed that effects on new or enlarging T2- or gadolinium (Gd)-enhancing lesions at 24 months were similar (mean difference (MD) -0.01, 95% CI -0.28 to 0.26, and MD -0.14, 95% CI -0.30 to 0.02, respectively). However, the reduction in T2- and T1-weighted lesion volume was significantly greater in the groups given IFNs than in the GA groups (MD -0.58, 95% CI -0.99 to -0.18, P value 0.004, and MD -0.20, 95% CI -0.33 to -0.07, P value 0.003, respectively).The number of participants who dropped out of the study because of adverse events was similar in the two groups (RR 0.95, 95% CI 0.64 to 1.40).The quality of evidence for primary outcomes was judged as moderate for clinical end points, but for safety and some MRI outcomes (number of active T2 lesions), quality was judged as low.

AUTHORS' CONCLUSIONS

The effects of IFNs-beta and GA in the treatment of patients with RRMS, including clinical (e.g. patients with relapse, risk to progression) and MRI (Gd-enhancing lesions) activity measures, seem to be similar or to show only small differences. When MRI lesion load accrual is considered, the effect of the two treatments differs, in that IFNs-beta were found to limit the increase in lesion burden as compared with GA. Evidence was insufficient for a comparison of the effects of the two treatments on patient-reported outcomes, such as quality of life measures.

The effect of scheduled antibody testing on treatment patterns in interferon-treated patients with multiple sclerosis

Background

Many patients with relapsing-remitting multiple sclerosis (MS) treated with high-dose interferon-β (IFNβ) develop serum binding antibodies (BAb) and neutralizing antibodies (NAb). NAb reduces the biological activity of IFNβ, which contributes to clinical failure in these patients. We investigated whether access to antibody (Ab) test results would alter usual care of (IFNβ)-treated patients and whether BAb could predict NAb.

Methods

This was a randomized, controlled, open-label, parallel-group, multicenter study in patients with multiple sclerosis. Subjects (n = 1358) were randomly assigned to Ab testing or usual care. BAb and NAb titres were measured using standard assays. Primary and secondary outcomes were the proportion of patients whose IFNβ therapy changed and the type of and reasons for therapy changes.

Results

Therapy changes differed between the Ab testing and usual care arms (19.6% and 14.0%, respectively; p = 0 · 004). Results from Ab testing were more frequently reported as the reason for therapy change in the Ab testing arm than in the usual care arm (p < 0.0001). NAb and BAb positivity significantly increased the likelihood of therapy change and reduced IFNβ-associated adverse events. BAb titres were a significant predictor of NAb positivity (p = 0.0012). Initial BAb-positive and NAb-positive status in both study arms had a significant impact on the overall number of patients with a therapy change (p < 0.05).

Conclusion

Access to Ab test results impacted therapy management. BAb titres can predict NAb positivity in patients on high-dose IFNβ.

Immunotherapy of multiple sclerosis: the state of the art

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

Interferon beta failure predicted by EMA criteria or isolated MRI activity in multiple sclerosis

Objective:

The objective of this paper is to investigate four-year outcomes of interferon beta (IFNB)-treated patients with multiple sclerosis (MS) according to their clinical or magnetic resonance imaging (MRI) activity status at first year of treatment.

Methods:

A total of 370 patients with MS duration ≤5 years before IFNB start were followed-up for four years. The optimal threshold for one-year MRI activity that more accurately predicted subsequent relapses or disability worsening was identified. The risk of relapses and disability worsening after the first year was then estimated by propensity score (PS)-adjusted analyses in patients fulfilling European Medicines Agency (EMA) criteria for second-line escalation and in those with isolated MRI activity.

Results:

A total of 192 (51.9%) patients relapsed, and 66 (17.8%) worsened in disability from year 1 to 4 of follow-up. The more accurate threshold for one-year MRI activity was the occurrence of ≥1 enhancing or ≥2 new T2-lesions. An increased risk of relapses and disability worsening was found in either patients fulfilling EMA criteria (hazard ratio (HR) = 3.69, and HR = 6.02) and in those experiencing isolated MRI activity (HR = 3.15, and HR = 5.31) at first year of treatment, when compared with stable patients (all p values <0.001).

Conclusion:

The four-year outcomes of patients with isolated MRI activity did not differ from those fulfilling EMA criteria at first year of IFNB treatment.

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.

[Interferon-β1b in multiple sclerosis therapy: more than 20 years clinical experience]

The introduction of interferon-β1b in 1993 in the USA and 2 years later in Europe made it possible for the first time to alter the course of the disease in patients with relapsing-remitting multiple sclerosis (MS). Subsequently, interferon-β1b was approved for the treatment of patients with active secondary progressive MS (1999) and early relapsing-remitting MS following a first demyelinating event (clinically isolated syndrome, CIS) (2006). Here we provide an overview of the clinical experience gathered during more than 20 years of interferon-β use focusing on long-term efficacy and safety and the impact of early initiation of treatment. Furthermore, the following aspects will be discussed: putative mechanisms of action of interferon-β, indications for a disease-modifying therapy, clinical relevance of neutralizing antibodies, importance of adherence in MS therapy, high versus low frequency therapy, combination therapies with interferon-β and safety of interferon-β in children and adolescents with MS and during pregnancy.

The impact of neutralizing antibodies on the risk of disease worsening in interferon β-treated relapsing multiple sclerosis: a 5 year post-marketing study

The impact of neutralizing antibodies (NAbs) on interferon β (IFNβ) efficacy in MS patients is still an object of controversy. To evaluate the clinical response to IFNβ during NAb-positive (NAb+) and NAb-negative (NAb-) statuses on a large population of relapsing remitting (RR) MS patients were followed up to 5 years. Sera from 567 RR MS patients treated with IFNβ for 2-5 years were collected every 6-12 months and evaluated for NAb presence by a cytopathic effect assay. The relapse rate and expanded disability status scale (EDSS) score were assessed at baseline and every 6 months for each patient. A NAb+ status was defined after two consecutive positive titers of NAbs >/= 20 neutralizing units (NU)/mL. Multivariate models were used to analyze the relapse rate, the time to first relapse, the time to confirmed EDSS score 4 during NAb+ and NAb- statuses. A propensity score (PS) matching analysis was performed to assess the robustness of the multivariate models. Fourteen percent of patients became NAb+ during the follow-up. A significant increase of the relapse rate (IRR = 1.38; p = 0.0247) and decrease of the time to 1st relapse (IRR = 1.51; p = 0.0111) were found during NAb+ periods. The PS matching analysis, in a selected cohort of patients, demonstrated a negative trend of NAbs on the time to reach the milestone EDSS 4 (IRR = 2.94; p = 0.0879). This long-term post-marketing observational study further confirms that the occurrence of NAbs significantly affects the risk of disease worsening in IFNβ- treated RRMS.

Clinical testing for neutralizing antibodies to interferon-β in multiple sclerosis

Biopharmaceuticals are drugs which are based on naturally occurring proteins (antibodies, receptors, cytokines, enzymes, toxins), nucleic acids (DNA, RNA) or attenuated microorganisms. Immunogenicity of these agents has been commonly described and refers to a specific antidrug antibody response. Such immunogenicity represents a major factor impairing the efficacy of biopharmaceuticals due to biopharmaceutical neutralization. Indeed, clinical experience has shown that induction of antidrug antibodies is associated with a loss of response to biopharmaceuticals and also with hypersensitivity reactions. The first disease-specific agent licensed to treat multiple sclerosis (MS) was interferon-β (IFNβ). In its various preparations, it remains the most commonly used first-line agent. The occurrence of antidrug antibodies has been extensively researched in MS, particularly in relation to IFNβ. However, much controversy remains regarding the significance of these antibodies and incorporation of testing into clinical practice. Between 2% and 45% of people treated with IFNβ will develop neutralizing antibodies, and this is dependent on the specific drug and dosing regimen. The aim of this review is to discuss the use of IFNβ in MS, the biological and clinical relevance of anti-IFNβ antibodies (binding and neutralizing antibodies), the incorporation of testing in clinical practice and ongoing research in the field.

Serum levels of IL-17A in patients with relapsing–remitting multiple sclerosis treated with interferon-β

Background:

Interleukin-17 (IL-17), which is secreted by Th17 cells, is a proinflammatory cytokine that is implicated in the pathogenesis of multiple sclerosis (MS) and plays a role in nonresponse of MS patients to interferon-β (IFN-β) therapy.

Objectives:

The purpose of this study was to establish a correlation between nonresponders (NR) and IL-17A serum titers and binding antibodies (BAbs) to IFN-β, as well as to find a correlation between IL-17A serum levels and other features of MS patients.

Methods:

Our prospective study included 72 inactive relapsing–remitting multiple sclerosis (RRMS) patients that had been treated for at least 18 months with IFN-β and 15 healthy subjects. We determined the serum levels of IL-17A and of BAbs. IL-17A levels were considered elevated (IL-17A+) if the recorded value was greater than 1.6 pg/ml.

Results:

Twenty-seven patients (37.5%) were NR and had a significantly higher serum IL-17A level compared to the responders group. Nineteen patients (26.4%) were IL-17A+ and had had a significantly higher number of relapses in the previous year and a higher Expanded Disability Status Score. The majority of IL-17A+ patients were NR and had a shorter MS duration.

Conclusions:

RRMS patients with high serum IL-17A levels do not respond well to IFN-β therapy and have shorter MS duration compared to patients with low IL-17A levels. This response is not influenced by the presence of BAbs.

Interferon-beta-1b-induced short- and long-term signatures of treatment activity in multiple sclerosis

Interferon beta (IFNβ) reduces disease burden in relapsing-remitting multiple sclerosis (MS) patients. In this study, IFNβ-1b-treated MS patient gene expression profiles and biological knowledgebases were integrated to study IFNβ's pleiotropic mechanisms of action. Genes involved in immune regulation, mitochondrial fatty acid metabolism and antioxidant activity were discovered. Plausible mediators of neuronal preservation included NRF2, downregulation of OLA1, an antioxidant suppressor, and the antioxidant gene ND6, implicated in optic neuropathy and MS-like lesions. Network analysis highlighted IKBKE, which likely has a role in both viral response and energy metabolism. A comparative analysis of therapy-naive MS- and IFNβ-associated gene expression suggests an IFNβ insufficiency in MS. We observed more gene expression changes in long-term treatment than during acute dosing. These distinct short- and long-term effects were driven by different transcription factors. Multi-gene biomarker signatures of IFNβ treatment effects were developed and subsequently confirmed in independent IFNβ-1b-treated MS studies, but not in glatiramer acetate-treated patients.

Variability in detection and quantification of interferon β-1b-induced neutralizing antibodies

BACKGROUND

Interferon-beta (IFNB) therapy for multiple sclerosis can lead to the induction of neutralizing antibodies (NAbs) against IFNB. Various methods are used for detection and quantification of NAbs.

METHODS

Blood samples from 125 IFNB-1b-treated patients, which were tested NAb negative or NAb positive after conclusion of a clinical study, were retested three years after first being assessed in four different laboratories that offer routine NAb testing to practicing neurologists. The myxovirus protein A (MxA) induction assay, the cytopathic effect (CPE) assay (two laboratories), or the luciferase assay were used. Intra- and inter-laboratory agreement between assays with respect to NAb detection and NAb titer quantification were evaluated.

RESULTS

High agreement for NAb detection (kappa coefficient, 0.86) and for titer levels was observed for the intra-laboratory comparison in the laboratory using the MxA induction assay performed three years ago and now. A similarly high agreement for NAb detection (kappa coefficient, 0.87) and for titer quantification was noted for the MxA assay of this laboratory with one of two laboratories using the CPE assay. All other inter-laboratory comparisons showed kappa values between 0.57 and 0.68 and remarkable differences in individual titer levels.

CONCLUSIONS

There are considerable differences in the detection and quantification of IFNB-induced NAbs among laboratories offering NAb testing for clinical practice using different assay methods. It is important that these differences are considered when interpreting NAb results for clinical decision-making and when developing general recommendations for potentially clinically meaningful NAb titer levels.