Neutralizing antibodies to interferon beta: Assessment of their clinical and radiographic impact: An evidence report: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

Current and future role of interferon beta in the therapy of multiple sclerosis

Interferon beta was the first specific disease-modifying therapy licensed for multiple sclerosis (MS) and in its many forms remains the most commonly prescribed agent worldwide. It, however, has a modest effect in reducing relapse rates, magnetic resonance imaging activity, and disability, and many patients are unable to tolerate it because of the associated side effects or mode of administration. With the licensing of glatiramer acetate, natalizumab and mitoxantrone as disease-modifying therapies for MS alternative options are available to people with MS. Many exciting new therapies are also in the pipeline, namely, the monoclonal antibodies alemtuzumab, rituximab, and daclizumab and the promising oral agents BG00012, cladribine, fingolimod, laquinimod, and teriflunomide. In this article we review the immunopathology of MS and the proposed mechanisms of action of currently available and anticipated treatments. We also review the efficacy of each drug, use of combination therapy strategies, and the potential role of the interferon beta preparations in the future.

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.

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

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

Immunomodulatory drug treatment in multiple sclerosis

The fundamental role of inflammatory immune processes in the pathology of multiple sclerosis (MS) provides the rationale for immunomodulatory therapies that attempt to shift the immune system from pro-inflammatory to anti-inflammatory pathways and induce regulatory mechanisms. Growing understanding of immune cellular and molecular mechanisms together with modern biotechnology engendered promising immunomodulatory treatment strategies, with novel mechanisms of actions and different levels of specificity. These include inhibitory molecules, monoclonal antibodies, cell therapies and agents that are administered orally or by infrequent infusions. Several of these treatments have demonstrated impressive efficacy in Phase II and III clinical trials by reducing disease activity and accumulation of disability. However, with the advent of potent therapies, rare but severe adverse effects, such as CNS infections and malignancies, have occurred. This article describes current and upcoming immunomodulatory strategies for MS therapy. The potential of immunomodulatory treatments to counteract the inflammatory characteristics of MS and support neuroprotective processes is discussed.

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.

Polymorphisms of innate pattern recognition receptors, response to interferon-beta and development of neutralizing antibodies in multiple sclerosis patients

BACKGROUND

Interferon-beta therapy of patients with relapsing-remitting multiple sclerosis involves repeated 'immunizations' with exogenous protein solutions. Innate pattern recognition receptors play an important role in immune responses towards foreign substances and may thus be related to treatment outcome.

OBJECTIVE

To determine the genotypes at 42 single nucleotide polymorphism loci in selected pattern recognition receptors for 567 prospectively followed relapsing-remitting multiple sclerosis patients treated with recombinant interferon-beta, and test for relationships to several outcome parameters, including formation of interferon-beta neutralizing antibodies.

RESULTS

The results suggest an association between the rs5743810 polymorphism (Ser249Pro) of TLR6 and development of neutralizing antibodies after 24 months of therapy in males (p = 0.00002), but not in females (p = 0.2). This association survived crude Bonferroni correction (p (corrected) = 0.02). Additional associations were observed in carriers of the TLR2-rs5743708 and NOD2-rs3135499 SNPs (time to relapse), the TLR7-rs179008 and NOD1-rs2075820 SNPs (time to disease progression) and the TLR4-rs7873784, TLR9-rs5743836, and NOD2-rs2066842 SNPs (frequency of neutralizing antibodies development). All of these, however, failed to survive correction for multiple testing. There were no significant differences between interferon-beta responders and non-responders for any of the investigated single nucleotide polymorphisms.

CONCLUSIONS

The rs5743810 polymorphism of TLR6 may be involved in development of anti-interferon-beta antibodies in males, although further studies are required to firmly establish this.

Quality indicators for multiple sclerosis

Determining whether persons with multiple sclerosis (MS) receive appropriate, comprehensive healthcare requires tools for measuring quality. The objective of this study was to develop quality indicators for the care of persons with MS. We used a modified version of the RAND/UCLA Appropriateness Method in a two-stage process to identify relevant MS care domains and to assess the validity of indicators within high-ranking care domains. Based on a literature review, interviews with persons with MS, and discussions with MS providers, 25 MS symptom domains and 14 general health domains of MS care were identified. A multidisciplinary panel of 15 stakeholders of MS care, including 4 persons with MS, rated these 39 domains in a two-round modified Delphi process. The research team performed an expanded literature review for 26 highly ranked domains to draft 86 MS care indicators. Through another two-round modified Delphi process, a second panel of 18 stakeholders rated these indicators using a nine-point response scale. Indicators with a median rating in the highest tertile were considered valid. Among the most highly rated MS care domains were appropriateness and timeliness of the diagnostic work-up, bladder dysfunction, cognition dysfunction, depression, disease-modifying agent usage, fatigue, integration of care, and spasticity. Of the 86 preliminary indicators, 76 were rated highly enough to meet predetermined thresholds for validity. Following a widely accepted methodology, we developed a comprehensive set of quality indicators for MS care that can be used to assess quality of care and guide the design of interventions to improve care among persons with MS.

Clinical effects and tolerability of high-dose, high-frequency recombinant interferon beta-1a in patients with multiple sclerosis: maximizing therapy through long-term adherence

IMPORTANCE OF THE FIELD

High-dose, high-frequency IFN beta-1a in multiple sclerosis (MS) can prevent lesion formation, decrease the frequency/severity of relapses and delay progression of disability, with a proven safety profile. Rates of non-adherence are high. There are drugs under investigation that may have greater efficacy and different safety profiles from existing therapies.

AREAS COVERED IN THIS REVIEW

Evidence supporting the efficacy of IFN beta-1a, factors contributing to non-adherence, and strategies to combat non-adherence. It is hoped that these strategies, coupled with future advances in pharmacogenetics, might lead to better outcomes. The PubMed database was searched using the terms "multiple sclerosis" and "interferon beta-1a", for papers published between 1998 and 2010. Relevant manuscripts and pivotal papers from clinical trials were cited. Searches of abstracts from congresses were also performed to obtain recent findings.

WHAT THE READER WILL GAIN

An overview of early pivotal trials, comparative studies with other treatments, and recent studies assessing the development of this therapy.

TAKE HOME MESSAGE

Long-term treatment with IFN beta-1a has benefits in MS and a good safety profile. Although adherence outside of clinical trials can be poor, injection devices, better tolerated drug formulations and education regarding treatment expectations are some of the strategies employed to help patients to adhere to treatment in the hope of improving outcomes.

A novel strategy to reduce the immunogenicity of biological therapies

Biological therapies, even humanized mAbs, may induce antiglobulin responses that impair efficacy. We tested a novel strategy to induce tolerance to a therapeutic mAb. Twenty patients with relapsing-remitting multiple sclerosis received an initial cycle of alemtuzumab (Campath-1H), up to 120 mg over 5 d, preceded by 500 mg SM3. This Ab differs from alemtuzumab by a single point mutation and is designed not to bind to cells. Twelve months later, they received a second cycle of alemtuzumab, up to 72 mg over 3 d. One month after that, 4 of 19 (21%) patients had detectable serum anti-alemtuzumab Abs compared with 145 of 197 (74%) patients who received two cycles of alemtuzumab without SM3 in the phase 2 CAMMS223 trial (p < 0.001). The efficacy and safety profile of alemtuzumab was unaffected by SM3 pretreatment. Long-lasting "high-zone" tolerance to a biological therapy may be induced by pretreatment with a high i.v. dose of a drug variant, altered to reduce target-binding.

Update on the treatment options for multiple sclerosis

Recent progress in the treatment of multiple sclerosis (MS) is remarkable, and the introduction of new therapies is yielding improvements in the management of MS. Furthermore, clinical trials with many different types of agents, especially selected monoclonal antibodies, have been undertaken or are ongoing, and some of the agents involved will probably be available as treatments for MS in the near future. Although these new and promising agents include targeted immunotherapies, some of them have limitations such as associated severe adverse events and the development of neutralizing antibodies. With regard to risk-benefit ratios, pharmacogenetics could shed light on inherited differences in drug metabolism and response, which would make individualized therapy possible in MS. Here, we review the recent progress in current therapeutic strategies for MS, and the potential options for future MS treatment.

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.

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

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

The neutralization of interferons by antibody III. The constant antibody bioassay, a highly sensitive quantitative detector of low antibody levels

The neutralizing antibodies (NAbs) that develop in patients during interferon (IFN) therapy can reduce its beneficial effects. The universally employed method of NAb measurement currently is the constant IFN method, in which antigen at a single given concentration is mixed with serial dilutions of serum, the lowest final dilution of which (usually 1:20) is constrained by the potential adverse effect of human serum on human cells in culture. The constant antibody (Ab) method described herein uses serum at a certain set dilution (usually 1:20) mixed with a series of IFN concentrations. Theoretical neutralization curves based on the previously presented model of the Ab-IFN reaction are depicted herein in terms of experimentally observable quantities. As predicted by the theoretical studies, the constant Ab method was demonstrated experimentally to extend the lower limits of detection of Ab by a factor of 10-20. The excellent agreement observed between the theoretical prediction and experimental findings reinforces the validity of using as NAb unitage the titer based on 10-fold reduction of IFN activity, reportable as Tenfold Reduction Units (TRU)/mL, as previously recommended. Testing by the constant Ab method of sera previously considered negative (<20 TRU/mL by the constant IFN method) from patients treated with Rebif or Betaseron showed that approximately 50% had detectable NAbs; such sera from Avonex-treated patients had titers of <1 TRU/mL. The constant Ab method can be used as a quantitative, sensitive IFN NAb screening bioassay of any nature, and should be able to detect low levels of NAbs early in the course of IFN therapy. The method may be useful to test monoclonal antibodies for otherwise undetectable NAbs. In principle, the constant Ab method should be applicable to the measurement of NAbs against any cytokine or other protein-effector molecule.

Neutralizing antibodies to 500 μg interferon beta-1b: 28-month results of the IDEAS extension trial

The Interferon Dose Escalation Assessment of Safety extension trial monitored neutralizing antibodies to interferon beta-1b in patients who currently or had previously received the double dose (500 μg) for up to 28 months. Fifteen patients entered the extension trial; five patients were neutralizing antibody-positive at the start of the trial. The present study demonstrates that when neutralizing antibodies develop in patients receiving higher doses of interferon beta-1b they tend to persist for a prolonged period, although neutralizing antibody titers tend to decrease over time and some patients may revert to neutralizing antibody-negative status.

Neutralizing antibodies explain the poor clinical response to interferon beta in a small proportion of patients with multiple sclerosis: a retrospective study

Background

Neutralizing antibodies (NAbs) against Interferon beta (IFNβ) are reported to be associated with poor clinical response to therapy in multiple sclerosis (MS) patients. We aimed to quantify the contribution of NAbs to the sub-optimal response of IFNβ treatment.

Methods

We studied the prevalence of NAbs in MS patients grouped according to their clinical response to IFNβ during the treatment period. Patients were classified as: group A, developing ≥ 1 relapse after the first 6 months of therapy; group B, exhibiting confirmed disability progression after the first 6 months of therapy, with or without superimposed relapses; group C, presenting a stable disease course during therapy. A cytopathic effect assay tested the presence of NAbs in a cohort of ambulatory MS patients treated with one of the available IFNβ formulations for at least one year. NAbs positivity was defined as NAbs titre ≥ 20 TRU.

Results

Seventeen patients (12.1%) were NAbs positive. NAbs positivity correlated with poorer clinical response (p < 0.04). As expected, the prevalence of NAbs was significantly lower in Group C (2.1%) than in Group A (17.0%) and Group B (17.0%). However, in the groups of patients with a poor clinical response (A, B), NAbs positivity was found only in a small proportion of patients.

Conclusion

The majority of patients with poor clinical response are NAbs negative suggesting that NAbs explains only partially the sub-optimal response to IFNβ.

Recognizing and treating suboptimally controlled multiple sclerosis: steps toward regaining command

OBJECTIVE

The therapies available today for multiple sclerosis (MS) reduce but do not fully control disease activity. The objective of this article is to review the definitions of and treatments for suboptimally controlled MS and highlight the challenges faced by clinicians to increase awareness of recognizing and managing patients with suboptimally controlled MS.

METHODS

Published literature describing treatment failure, treatment optimization paradigms or algorithms, clinical studies of therapies in patients with suboptimally controlled MS, or case reports of management of patients with suboptimally controlled MS were identified from searches of EMBASE and MEDLINE. This was supplemented with case reports and discussions from an expert panel meeting of MS specialists focused on the diagnosis and treatment of suboptimally controlled MS.

RESULTS

Several groups have created recommendations for evaluating suboptimal response to disease-modifying drugs (DMDs) in MS. Currently no robust evidence-based data exist to guide treatment decisions in patients who have suboptimal response to a particular therapy. In the absence of data, several treatment paradigms for suboptimally controlled MS have been proposed using a step therapy or platform therapy approach. Therapy modifications require consideration of disease- and patient-specific factors while accounting for the risk-benefit profile of the agent(s). Unapproved drugs and combination therapies should be reserved as agents of last resort because of the experimental nature of these treatments.

CONCLUSIONS

In the absence of evidence-based data, identifying and treating MS patients with suboptimal response to the available platform therapies remains challenging. Developing algorithms able to quantify breakthrough disease activity and suboptimal response to DMDs in individual MS patients remains an important target for the MS community. Consideration should be given for all reasons why a particular DMD may not be working for a given patient and for the use of an individualized step therapy.

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

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

Improving compliance with interferon-beta therapy in patients with multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease affecting young adults (with a peak of onset between the ages of 20 and 40 years). In 80-90% of cases, it is characterized by an early relapsing-remitting (RR) inflammatory phase, followed by a secondary progressive course in which disability progressively accumulates. Interferon-beta (IFNbeta) therapies represent the first-line treatment of RRMS. There are three IFNbeta formulations currently licensed for RRMS. Two are formulations of INFbeta-1a, one administered at a dosage of 30 mug intramuscularly weekly (Avonex(R)) and the other administered at a dosage of 22 or 44 microg subcutaneously (SC) three times a week (Rebif(R) 22 and 44). The third is a formulation of IFNbeta-1b, administered at a dosage of 250 microg SC every other day (Betaseron(R)). These treatments reduce the frequency of acute relapses and, to a lesser extent, disability progression. However, when starting an IFNbeta therapy, a treatment discontinuation rate ranging from 14% to 44% has to be expected. In a sizable proportion of patients, treatment suspension is caused by the occurrence of adverse effects (most commonly a flu-like syndrome and injection site reactions) and/or poor compliance. Individualized patient education and support are critical to improve adherence to therapy in the long term. Approaches aimed at reducing the proportion of subjects interrupting IFNbeta encompass both pharmacological and non-pharmacological interventions, and may involve several professional figures, such as the neurologist, the psychologist, the pharmacist, the physical and speech therapist, and the nurse. Recently, the development of new IFNbeta formulations, with reduced immunogenic potential, has offered an additional approach to improving patient adherence. Biferonex(R) is a pH neutral and human serum albumin-free IFNbeta-1a. A phase III, 2-year study of the product involving patients with RRMS has been conducted, but the results were not considered conclusive enough to allow approval in Europe. Rebif(R) New Formulation (RNF) is a formulation of INFbeta-1a that is not produced using fetal bovine serum and that does not have human serum albumin as an excipient. The formulation has been approved in Europe and an application for approval has been filed in the US. On the basis of the final analysis of a phase III trial, RNF showed higher tolerability, particularly in terms of injection site reactions, compared with the older formulation. Further studies assessing its usefulness as an alternative therapy for patients who are intolerant of other IFNbeta formulations are required.

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.

Current approaches to the identification and management of breakthrough disease in patients with multiple sclerosis

Disease-modifying drugs (DMDs) for relapsing-remitting multiple sclerosis (RRMS) are only partly effective -- breakthrough disease commonly occurs despite treatment. Breakthrough disease is predictive of continued disease activity and a poor prognosis. Availability of several DMDs offers the possibility of tailoring treatment to individual patients with RRMS and altering treatment in patients with breakthrough disease. However, no biological or imaging markers have been validated to guide initial treatment, markers of individual responsiveness to DMDs are scarce, and there is no class 1 evidence to guide alternative therapy in patients with breakthrough disease. In this Review, we discuss proposed strategies to monitor patients with RRMS being treated with DMDs, outline approaches to identifying therapeutic response in individual patients, review MRI and biological markers of treatment response, and summarise the role of antibodies in biological therapies. We also outline possible strategies for the management of patients with breakthrough disease and highlight areas in which research is needed.

High-dose intravenous interferon beta in patients with neutralizing antibodies (HINABS): a pilot study

Background

Neutralizing antibodies (NABs) against interferon beta (IFNβ) are associated with a loss of IFNβ bioactivity and clinical effectiveness. To date, there are no anti-NAB strategies available. The primary objective of this trial was to investigate whether intravenous IFNβ-1b can restore bioactivity in NAB-positive patients with MS.

Methods

NAB-positive patients with MS were treated with 8 MIU IFNβ-1b s.c., 8 MIU i.v., and 16 MIU i.v. Each application was preceded by a wash-out period of 1 week. Blood samples were collected before, 3, 12, and 24 h after each administration. Myxovirus protein A (MxA) RNA and protein levels were determined. The study has been approved by the local ethics committee.

Results

Five patients completed the study. NAB titers ranged from 42 to 4482 neutralizing units. Median MxA protein (1821, range 12–3234) and RNA (2186, range 114–7525) area under the curve levels for the four measurements at each IFNβ injection were significantly higher after i.v. application of 16 MIU as compared with both 8-MIU dosages, which were 743 (0–2709) for MxA protein after 8 MIU i.v. and 254 (0–1200) after s.c., and 1763 (25–7188) for MxA RNA after 8 MIU i.v., and 557 (5–2265) after s.c. applications. NAB titers decreased significantly and transiently after infusion of 16 MIU IFNβ-1b but not after both forms of 8 MIU applications. Typical side effects could be controlled by paracetamol. No allergic reaction was observed.

Discussion

The results indicate that i.v. administration of IFNβ can restore bioavailability of IFNβ in patients with NABs.

High-dose, high-frequency recombinant interferon beta-1a in the treatment of multiple sclerosis

BACKGROUND

There is at present no cure for multiple sclerosis (MS), and existing therapies are designed primarily to prevent lesion formation, decrease the rate and severity of relapses and delay the resulting disability by reducing levels of inflammation.

OBJECTIVE

The aim of this review was to assess the treatment of relapsing MS with particular focus on subcutaneous (s.c.) interferon (IFN) beta-1a.

METHOD

The literature on IFN beta-1a therapy of MS was reviewed based on a PubMed search (English-language publications from 1990) including its pharmacodynamics and pharmacokinetics, clinical efficacy in relapsing MS as shown in placebo-controlled studies and in comparative trials, efficacy in secondary progressive MS, safety and tolerability, and the impact of neutralizing antibodies.

CONCLUSION

The literature suggests that high-dose, high-frequency s.c. IFN beta-1a offers an effective option for treating patients with relapsing MS, with proven long-term safety and tolerability, and has a favourable benefit-to-risk ratio compared with other forms of IFN beta.

Optimizing Outcomes in Multiple Sclerosis – A Consensus Initiative

Background

Initiation of immunomodulators in patients experiencing a clinically isolated syndrome (CIS) may delay progression to clinically definite MS. However, lack of consensus remains on many issues affecting optimal management of MS.

Method

A panel of 21 MS experts met during 9 meetings to explore key issues in MS and CIS. Meetings addressed 3 phases: 1. CIS definition and diagnosis; 2. initial therapy; and 3. monitoring disease progression and treatment efficacy. Newsletters covering each phase were sent to 5000 U.S.-based neurologists who were invited to participate in an online survey on key issues.

Results

Most panel members agreed that early treatment may minimize neurodegeneration and most would recommend it for patients; that a dose-response relationship exists for beta-interferon therapy; that more aggressive therapy was most effective early in the disease course; and, that MRI has a role in monitoring disease progression. In face of suboptimal response, most would switch patients to a different therapy; while combination therapy would be reserved for those failing monotherapy regimes. Most online survey respondents agreed with these positions.

Conclusions

There was uniform consensus from this panel of MS experts that early initiation of immunomodulator therapy was beneficial for CIS patients.

Interferon-beta1b for the treatment of multiple sclerosis

BACKGROUND

Multiple sclerosis is a debilitating autoimmune disorder that causes disability in young adults.

OBJECTIVE

To review the efficacy and safety of IFN-beta1b in the management of relapsing-remitting and secondary progressive multiple scleroses and clinical isolated syndrome.

METHODS

A MEDLINE (1966-May 2007) search of clinical trials using the terms 'multiple sclerosis' and 'interferon' was performed. Manual bibliographic search was conducted. English-language articles were evaluated.

RESULTS

IFN-beta1b is more efficacious than placebo and at least as efficacious as IFN-beta1a or glatiramer for the management of relapsing-remitting multiple sclerosis. IFN-beta1b also delayed the time to diagnosis of definite multiple sclerosis and reduced brain lesion burden in patients with clinical isolated syndrome. More long-term, large scale clinical data are warranted to ascertain its relative efficacy compared to other treatments.

CONCLUSION

IFN-beta1b is an effective treatment for multiple sclerosis. Common side effects are lymphopenia, injection site reactions, asthenia, flu-like symptoms and headache.

Interferon-beta bioactivity measurement in multiple sclerosis: feasibility for routine clinical practice

BACKGROUND

Neutralising antibodies (NAb) to interferon beta (IFN beta) are associated with a reduced bioactivity and efficacy of IFN beta in multiple sclerosis (MS). Unclear is how to apply IFN beta bioactivity measurements (quantification of Myxovirus resistance protein A (MxA) mRNA) in clinical practice.

OBJECTIVES

To evaluate value and feasibility of IFN beta bioactivity measurement with a single MxA mRNA measurement for screening and a second measurement before and after IFN beta administration for definite confirmation of IFN beta bioactivity status.

METHODS

In 79 MS patients MxA mRNA expression was determined 4 hours after IFN beta administration. If inadequate, MxA mRNA expression testing was repeated 3 months afterwards, comparing post- and pre injection samples to determine whether IFNb bioactivity was persistently lacking. MxA mRNA expression was compared to NA beta titres, determined by the cytopathic effect assay (CPE).

RESULTS

NAb titres correlated significantly with MxA mRNA expression and MxA mRNA induction. Of all screened patients, only one patient had adequate MxA mRNA expression and high NAb titres simultaneously. Of the biological non-responders at second measurement (21/55), 17 (81%) were high-titre NAb positive, 1 (5%) was low-titre NAb positive and 3 (14%) were NAb negative. Without considering the pre-injection measurement, two more NAb negative patients would have tested negative for IFN beta bioactivity, emphasizing the need of a pre-injection sample.

CONCLUSIONS

Our data suggest that for IFN beta bioactivity screening a single post-injection measurement seems reasonable. However, MxA induction measurement based on both pre- and post-IFN beta injection samples at second measurement is somewhat more precise in determining ultimate IFN beta bioactivity status.

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.