A randomized, double-blind, dose-comparison study of weekly interferon beta-1a in relapsing MS

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.

Gender effects on intramuscular interferon beta-1a in relapsing–remitting multiple sclerosis: analysis of 1406 patients

Background: We aimed to evaluate effects of gender on efficacy and safety of intramuscular (IM) interferon beta (IFNβ)-1a in patients with relapsing–remitting MS (RRMS) or clinically isolated syndromes (CIS) characteristic of early MS.

Methods: Pooled data from 1406 (1027 women; 379 men) patients enrolled in five clinical studies of IM IFNβ-1a were analyzed. One analysis examined data for all patients treated with IM IFNβ-1a from all studies. Separate analyses were conducted of pooled IM IFNβ-1a-treated groups from all studies and pooled IFNβ-1a-treated and placebo-treated patients from the placebo-controlled studies. Outcome measures included time to first relapse, annualized relapse rate, time to disability progression, number of gadolinium-enhanced lesions, adverse events, laboratory evaluations, and neutralizing antibodies.

Results: All efficacy assessments indicated similar treatment effects of IM IFNβ-1a in men and women with no significant treatment-by-gender interactions. Women reported more headaches, urinary tract infections, and depression in the analysis; however, these were also common in women who received placebo. Men reported more frequent flu-like symptoms in the placebo-controlled studies only. There were no other differences in the safety profile of IM IFNβ-1a between men and women.

Conclusions: We conclude that no significant gender-related differences were found in the efficacy and safety of IM IFNβ-1a in patients with RRMS or CIS.

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.

Surrogate endpoints for EDSS worsening in multiple sclerosis. A meta-analytic approach

OBJECTIVE

To evaluate whether the effects on potential surrogate endpoints, such as MRI markers and relapses, observed in trials of experimental treatments are able to predict the effects of these treatments on disability progression as defined in relapsing-remitting multiple sclerosis (RRMS) trials.

METHODS

We used a pooled analysis of all the published randomized controlled clinical trials in RRMS reporting data on Expanded Disability Status Scale (EDSS) worsening and relapses or MRI lesions or both. We extracted data on relapses, MRI lesions, and the proportion of progressing patients. A regression analysis weighted on trial size and duration was performed to study the relationship between the treatment effect observed in each trial on relapses and MRI lesions and the observed treatment effect on EDSS worsening.

RESULTS

A set of 19 randomized double-blind controlled trials in RRMS were identified, for a total of 44 arms, 25 contrasts, and 10,009 patients. A significant correlation was found between the effect of treatments on relapses and the effect of treatments on EDSS worsening: the adjusted R(2) value of the weighted regression was 0.71. The correlation between the treatment effect on MRI lesions and EDSS worsening was slightly weaker (R(2) = 0.57) but significant.

CONCLUSIONS

These findings support the use of commonly used surrogate markers of EDSS worsening as endpoints in multiple sclerosis clinical trials. Further research is warranted to validate surrogate endpoints at the individual level rather than at the trial level, to draw important conclusions in the management of the individual patient.

A health-economic evaluation of disease-modifying drugs for the treatment of relapsing-remitting multiple sclerosis from the German societal perspective

OBJECTIVE

This analysis compared the cost-effectiveness of interferon beta-1a (IFNbeta-1a) 44 microg SC with that of other available first-line treatments for relapsing-remitting multiple sclerosis (RRMS) from the German societal perspective in 2008.

METHODS

A decision-analytic model was used to estimate the cost-effectiveness of IFNbeta-1a 44 microg SC given 3 times weekly compared with that of IFNbeta-la 30 microg IM given once weekly, IFNbeta-1b 8 mIU given every other day, and glatiramer acetate 20 mg SC given once daily. Data sources included the published literature, clinical trials, German price/tariff lists, and national population statistics. The time horizon of the model was 4 years, which was the maximum duration of follow-up in published clinical trials.

RESULTS

The cost-effectiveness (cost per relapse avoided) of IFNbeta-la 44 microg SC compared with no active treatment was euro51,250, which compared favorably with that of IFNbeta-la 30 microg IM (euro133,770), glatiramer acetate (euro71,416), and IFNbeta-1b (euro54,475). When the cost of disease progression was excluded, the cost per relapse avoided remained favorable for IFNbeta-1a 44 microg SC (euro54,292) compared with the other options (euro143,186, euro72,809, and euro56,816, respectively). Indirect comparison of each available treatment option with the next best alternative indicated that the incremental cost-effectiveness of IFNbeta-la 44 microg SC (euro23,449) was consistent with accepted thresholds. Sensitivity analyses in which the discount rate, frequency of relapse and disease progression, costs of relapse and disease progression, and adherence were varied did not affect the relative outcomes.

CONCLUSION

In this analysis from the German societal perspective, IFNbeta-la 44 microg SC had favorable overall cost-effectiveness versus no active treatment compared with other available disease-modifying drugs for the treatment of RRMS.

The role of glatiramer acetate in the early treatment of multiple sclerosis

The treatment of the underlying disease process causing multiple sclerosis has continued to evolve since the initial approval of interferon-beta-1b in 1993. Current emphasis is on early treatment, including treatment after a single clinical attack (clinically isolated syndrome). The assessment of which disease modifying medication to use as initial therapy has continued to remain a combination of science and the art of medicine. Equally important are the assessment of treatment failure and the subsequent choice of medication change. This article will present scientific information, as well as information about clinical decision making, about these choices, with emphasis on the changing role of glatiramer acetate in this process.

An imbalance of two functionally and phenotypically different subsets of plasmacytoid dendritic cells characterizes the dysfunctional immune regulation in multiple sclerosis

Plasmacytoid dendritic cells (pDCs) are instrumental in peripheral T cell tolerance and innate immunity. How pDCs control peripheral immunetolerance and local parenchymal immune response and contribute to the altered immunoregulation in autoimmune disorders in humans is poorly understood. Based on their surface markers, cytokine production, and ability to prime naive allogenic T cells, we found that purified BDCA-2(+)BDCA-4(+) pDCs consist of at least two separate populations, which differed in their response to oligodeoxynucleotides and IFNs (IFN-beta), and differently induced IL-17- or IL-10-producing T cells. To evaluate the potential immunoregulatory role of these two types of pDCs in multiple sclerosis (MS) and other human autoimmune disorders (myasthenia gravis), we studied the phenotype and regulatory function of pDCs isolated from clinically stable, untreated patients with MS (n = 16). Patients with MS showed a reversed ratio of pDC1/pDC2 in peripheral blood (4.4:1 in healthy controls, 0.69:1 in MS), a phenomenon not observed in the other autoimmune disorders. As a consequence, MS pDCs had an overall propensity to prime IL-17-secreting cells over IL-10-secreting CD4+ T cells. Immunomodulatory therapy with IFN-beta induced an increase of the pDC1 population in vivo (n = 5). Our data offer a plausible explanation for the disturbed immune tolerance in MS patients and provide evidence that immunomodulatory therapy acts at the level of reconstituting homeostasis of pDC, thus reconstituting the disturbed balance.

Oral fingolimod or intramuscular interferon for relapsing multiple sclerosis

BACKGROUND

Fingolimod (FTY720), a sphingosine-1-phosphate-receptor modulator that prevents lymphocyte egress from lymph nodes, showed clinical efficacy and improvement on imaging in a phase 2 study involving patients with multiple sclerosis.

METHODS

In this 12-month, double-blind, double-dummy study, we randomly assigned 1292 patients with relapsing-remitting multiple sclerosis who had a recent history of at least one relapse to receive either oral fingolimod at a daily dose of either 1.25 or 0.5 mg or intramuscular interferon beta-1a (an established therapy for multiple sclerosis) at a weekly dose of 30 microg. The primary end point was the annualized relapse rate. Key secondary end points were the number of new or enlarged lesions on T(2)-weighted magnetic resonance imaging (MRI) scans at 12 months and progression of disability that was sustained for at least 3 months.

RESULTS

A total of 1153 patients (89%) completed the study. The annualized relapse rate was significantly lower in both groups receiving fingolimod--0.20 (95% confidence interval [CI], 0.16 to 0.26) in the 1.25-mg group and 0.16 (95% CI, 0.12 to 0.21) in the 0.5-mg group--than in the interferon group (0.33; 95% CI, 0.26 to 0.42; P<0.001 for both comparisons). MRI findings supported the primary results. No significant differences were seen among the study groups with respect to progression of disability. Two fatal infections occurred in the group that received the 1.25-mg dose of fingolimod: disseminated primary varicella zoster and herpes simplex encephalitis. Other adverse events among patients receiving fingolimod were nonfatal herpesvirus infections, bradycardia and atrioventricular block, hypertension, macular edema, skin cancer, and elevated liver-enzyme levels.

CONCLUSIONS

This trial showed the superior efficacy of oral fingolimod with respect to relapse rates and MRI outcomes in patients with multiple sclerosis, as compared with intramuscular interferon beta-1a. Longer studies are needed to assess the safety and efficacy of treatment beyond 1 year. (ClinicalTrials.gov number, NCT00340834.)

Additive effects of combination treatment with anti-inflammatory and neuroprotective agents in experimental autoimmune encephalomyelitis

We studied the effects of combination treatment with an anti-inflammatory agent, interferon (IFN)-beta, and a putative neuroprotective agent, an estrogen receptor (ER)-beta ligand, during EAE. Combination treatment significantly attenuated EAE disease severity, preserved axonal densities in spinal cord, and reduced CNS inflammation. Combining ERbeta treatment with IFNbeta reduced IL-17, while it abrogated IFNbeta-mediated increases in Th1 and Th2 cytokines from splenocytes. Additionally, combination treatment reduced VLA-4 expression on CD4+ T cells, while it abrogated IFNbeta-mediated decreases in MMP-9. Our data demonstrate that combination treatments can result in complex effects that could not have been predicted based on monotherapy data alone.

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

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

The future of multiple sclerosis treatment

Recent years have seen considerable evolution and increasing sophistication of our concepts of the pathophysiology of multiple sclerosis. These new notions include the increased recognition of the importance of extralesional pathology, of the interplay between inflammation and neurodegenerative changes, pathophysiological heterogeneity and additional immune cell populations contributing to disease. These advances have driven the development and evaluation of new therapeutic strategies and outcome measures for clinical trials. A sizeable number of new immunomodulatory and immunosuppressive agents are under development and attracting great attention. These may offer potential advantages over existing treatments in terms of convenience and efficacy, but certain agents may raise safety concerns. In addition, neuroprotective and repair strategies are beginning to be considered. Not all of these agents will eventually be marketed but they will all help us gain insight into the pathophysiology of multiple sclerosis and decipher the mechanisms that underlie its heterogeneity. The place that these therapies will come to occupy in future years will depend on their relative benefits and risks.

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.

Dose response to interferon therapy in multiple sclerosis: an evaluation of the evidence

BACKGROUND

Interferon beta (IFNbeta) is a disease-modifying therapy for multiple sclerosis (MS). Although clinical benefits have been demonstrated in several large, randomized, double-blind studies, the optimal dosing of IFNbeta is controversial.

METHODS

A search was conducted using the key words IFNbeta, multiple sclerosis, Avonex, Rebif, Betaseron/Betaferon, efficacy, MRI, and dose-response relationship in MEDLINE, EMBASE, and other databases to locate relevant pivotal clinical trials, other prospective studies, and systematic reviews evaluating the efficacy and tolerability of IFNbeta published between 1985 and 2007. This review summarizes the findings of these studies with regard to defining the value of high-dose, high-frequency (HDHF) IFNbeta regimens.

REVIEW SUMMARY

All IFNbeta formulations and dosages have demonstrated efficacy in well-designed phase 3 trials. Two head-to-head trials suggesting that HDHF regimens result in increased efficacy contained shortfalls in study design that precluded definitive conclusions.

CONCLUSION

Defining the optimal dose and frequency strategy for IFNbeta in patients with MS is complicated by the differences in dosage, route, and frequency of administration among the various agents. Results of well-controlled pivotal trials do not suggest that HDHF IFNbeta regimens provide better long-term benefits for patients with MS than low-dose or low-frequency regimens. In addition, HDHF therapies may increase the incidence of side-effects and neutralizing antibodies that reduce efficacy over time. Although the two head-to-head comparisons of different IFNbeta therapies found HDHF regimens to be more efficacious than lower-dose/lower-frequency regimens, the design limitations of these studies must be considered when weighing the potential value of the findings for recommending treatment strategies.

Magnetic resonance imaging as a potential surrogate for relapses in multiple sclerosis: a meta-analytic approach

OBJECTIVE

The aim of this work was to evaluate whether the treatment effects on magnetic resonance imaging (MRI) markers at the trial level were able to predict the treatment effects on relapse rate in relapsing-remitting multiple sclerosis.

METHODS

We used a pooled analysis of all the published randomized, placebo-controlled clinical trials in relapsing-remitting multiple sclerosis reporting data both on MRI variables and relapses. We extracted data on relapses and on MRI "active" lesions. A regression analysis weighted on trial size and duration was performed to study the relation between the treatment effect on relapses and the treatment effect on MRI lesions. We validated the estimated relation on an independent set of clinical trials satisfying the same inclusion criteria but with a control arm other than placebo.

RESULTS

A set of 23 randomized, double-blind, placebo-controlled trials in relapsing-remitting multiple sclerosis was identified, for a total of 63 arms, 40 contrasts, and 6,591 patients. A strong correlation was found between the effect on the relapses and the effect on MRI activity. The adjusted R(2) value of the weighted regression line was 0.81. The regression equation estimated using the placebo-controlled trials gave a satisfactory prediction of the treatment effect on relapses when applied to the validation set.

INTERPRETATION

More than 80% of the variance in the effect on relapses between trials is explained by the variance in MRI effects. Smaller and shorter phase II studies based on MRI lesion end points may give indications also on the effect of the treatment on relapse end points.

Basic and escalating immunomodulatory treatments in multiple sclerosis: current therapeutic recommendations

This review updates and extends earlier Consensus Reports related to current basic and escalating immunomodulatory treatments in multiple sclerosis (MS). The recent literature has been extracted for new evidence from randomized controlled trials, open treatment studies and reported expert opinion, both in original articles and reviews, and evaluates indications and safety issues based on published data. After data extraction from published full length publications and critically weighing the evidence and potential impact of the data, the review has been drafted and circulated within the National MS Societies and the European MS Platform to reach consensus within a very large group of European experts, combining evidence-based criteria and expert opinion where evidence is still incomplete. The review also outlines a few areas of controversy and delineates the need for future research.

Avonex Combination Trial in relapsing—remitting MS: rationale, design and baseline data

Objective To review the rationale, design and baseline data of the Avonex Combination Trial (ACT), an investigator-run study of intramuscular interferon beta-1a (IM IFNβ-1a) combined with methotrexate (MTX) and/or IV methylprednisolone (IVMP) in relapsing—remitting multiple sclerosis (RRMS) patients with continued disease activity on IM IFNβ-1a monotherapy.

Methods Eligibility criteria included RRMS, Expanded Disability Status Scale score 0—5.5, and ≥1 relapse or gadolinium-enhancing MRI lesion in the prior year while on IM IFNβ-1a monotherapy. Subjects continued IFNβ-1a 30 mcg IM weekly and were randomized in a 2 × 2 factorial design to adjunctive weekly placebo or MTX 20 mg PO, with or without IVMP 1000 mg/day for three days every other month. ACT was industry-supported, and collaboratively designed and governed by an Investigator Steering Committee with independent Advisory and Data Safety Monitoring Committees. Study operations, MRI analysis and aggregated data were managed by the Cleveland Clinic MS Academic Coordinating Center.

Results In total 313 subjects were enrolled with clinical and MRI characteristics typical of RRMS. Most subjects (86.9%) qualified with a clinical relapse, with or without an enhancing MRI lesion, in the preceding year. At baseline, 21.4% had enhancing lesions, and 5.1% had anti-IFNβ neutralizing antibodies. ACT's management and operational structures functioned well.

Conclusion This study provides an innovative model for academic—industry collaborative MS research and will enhance understanding of the utility of combination therapy for RRMS patients with continued disease activity on an established first-line treatment. Multiple Sclerosis 2008; 14: 370—382. http://msj.sagepub.com

Neutralizing anti-interferon beta antibodies are associated with reduced side effects and delayed impact on efficacy of Interferon-beta

Interferon-beta (IFNbeta) is a biological therapy which is immunogenic, inducing anti-IFN-beta neutralizing antibodies (Nabs) in some subjects. The frequency of Nabs varies depending on IFN-beta product and the Nab assay used.

OBJECTIVE

Assess frequency of Nabs using novel Luciferase assay, evaluate association with relapses, frequency of side effects and to compare results with published data.

METHODS

Serum samples at 12 and 24 months and a follow up sample were tested for binding and Nabs. Titre >20 NU was considered positive. Charts were reviewed retrospectively for clinical data.

RESULTS

Out of 327 subjects included, 130 subjects (40%) were binding antibody positive, 89 (27%) were Nab +ve at anytime. Risk at 12 months for being Nab +ve: Avonex 8%, Betaferon 39%, Rebif 33%, P < 10(-5); at 24 months 8, 31 and 27% respectively, P = 0.002. Nab titres were highest in Rebif Nab +ve subjects - 50% >320 NU. Annualized relapse rate was 1.53 pre-treatment, after treatment relapse rate was higher in Nab +ve group 0.67 (95% CI 0.38-0.97) versus 0.5 (0.38-0.61) Nab -ve P = 0.04. Nab status at 12 and 24 months was significantly associated with risk of subsequent relapse, risk being greatest in those with highest titres. Side effects were also significantly associated with Nab -ve status.

Interferon-beta treatment for multiple sclerosis

Multiple sclerosis (MS) is the leading nontraumatic cause of neurologic disability in young adults. Interferon-beta, approved for use in 1993, was the first treatment to modify the course and prognosis of the disease and remains a mainstay of MS treatment. Numerous large-scale clinical trials in early, active patient populations have established the clinical efficacy of interferon-beta in reducing relapses and delaying disability progression. Although its mechanism of action remains incompletely understood, a reduction in active lesions seen on magnetic resonance imaging implies primary anti-inflammatory properties, a mechanism supported by basic immunologic research. Variation in individual patient responsiveness to interferon-beta may be due to disease variability or differential induction of interferon-stimulated genes. The magnitude of the therapeutic effect appears to be similar among products, but the optimal dose, route, and frequency of administration of the drug remain uncertain.

Immunogenicity and tolerability of an investigational formulation of interferon-beta1a: 24- and 48-week interim analyses of a 2-year, single-arm, historically controlled, phase IIIb study in adults with multiple sclerosis

BACKGROUND

RNF (Rebif New Formulation, Merck Serono International S.A., Geneva, Switzerland), a formulation of interferon-beta1a (IFN-beta1a) without human- or animal-derived components, is currently under investigation. It was developed with the aim of maximizing the treatment benefit for patients with multiple sclerosis (MS) by improving injection tolerability and reducing the development of neutralizing antibodies (NAbs).

OBJECTIVE

This paper reports the results of planned 24- and 48-week interim analyses comparing immunogenicity and tolerability data from an ongoing study of RNF with historical-control data for the currently approved formulation of IFN-beta1a from the EVIDENCE (EVidence of Interferon Dose-response: European North American Comparative Efficacy) study.

METHODS

Patients in the 96-week, multicenter, singlearm, Phase IIIb RNF study received 44 microg/0.5 mL SC tiw; patients in the EVIDENCE study received an identical regimen of the currently approved formulation of IFN-beta1a. Criteria for inclusion in the RNF study were age between 18 and 60 years, an Expanded Disability Status Scale (EDSS) score <6.0, and a diagnosis of relapsing MS (McDonald criteria). Criteria for inclusion in the EVIDENCE study were age between 18 and 55 years, an EDSS score of 0 to 5.5, and a diagnosis of clinically definite relapsing-remitting MS (Poser criteria). Patients in both studies were treatment naive. Both studies used the same cytopathic-effect assay for NAbs to assess immunogenicity; patients who had NAb titers >or=20 neutralizing units (NU)/mL were considered NAb+. The primary end point was to compare the proportions of NAb+ patients in the RNF study and the historical data. Comparisons were descriptive and used exact 95% CIs. Safety analyses included 8 prespecified adverse events (AEs) of interest.

RESULTS

Baseline demographic characteristics were well balanced between the RNF (N = 260) and EVIDENCE (N = 339) studies, except that patients in the RNF study were slightly younger (median age, 34.0 vs 39.0 years, respectively), and a few had secondary progressive MS (n = 6) or progressive relapsing MS (n = 1). At week 48, 87.3% of patients in the RNF study remained on treatment. The incidence of the prespecified AEs of interest in the RNF and EVIDENCE studies was as follows: flu-like symptoms (70.8% and 48.1%, respectively), injection-site reactions (29.6% and 83.8%), hepatic disorders (13.1% and 16.8%), cytopenia (9.6% and 11.8%), depression and suicidal ideation (5.8% and 19.8%), skin rashes (5.4% and 12.1%), hypersensitivity reactions (5.4% and 3.2%), and thyroid disorders (2.3% and 5.0%). Overall, the majority (96.9%) of AEs in the RNF study were mild (69.5%) or moderate (27.5%) in severity. The proportions of patients in the RNF and EVIDENCE studies with NAbs at both 24 and 48 weeks were 2.5% (95% CI, 0.9-5.5) and 14.3% (95% CI, 10.7-18.6), respectively; the proportions with NAbs at week 48 only were 13.9% (95% CI, 9.9-18.7) and 24.4% (95% CI, 19.9-29.4). The proportions of NAb+ patients with high NAb titers (>1000 NU/mL) at week 48 were 11.1% in the RNF study and 19.5% in the EVIDENCE study.

CONCLUSIONS

The results of these interim analyses suggest that RNF had an improved overall tolerability and safety profile and a lower immunogenic potential compared with the approved IFN-beta1a formulation assessed in the EVIDENCE study. Two-year results from the RNF study are anticipated before the end of 2007.

Using measurements of neutralizing antibodies: the challenge of IFN-? therapy

Although the occurrence of neutralizing antibodies (NAbs) to interferon (IFN)-beta has been acknowledged since the pivotal trials of IFN-beta in multiple sclerosis (MS), the effect of these antibodies has for several reasons been debated. The main reason for the controversies has been insufficient knowledge of the fact that clinically relevant NAbs do not appear until 12-18 months after initiation of IFN-beta therapy which make studies of 2 years or less unsuited to assess the clinical relevance of NAbs. Further, changes in NAb affinity occur and contribute to increase NAb effects by time. The present paper reviews our current knowledge of NAbs and stresses the importance of using measurements of NAbs routinely. It is concluded that NAb titres are important for the biological response to IFN-beta. Patients with low or intermediate titres may have preserved a full or partial biological response and might still benefit from IFN-beta therapy. However, persistent high titres of NAbs indicate an abrogation of the biological response and, hence, absence of therapeutic efficacy, and this observation should lead to a change of therapy. The application of the existing information about NAbs in clinical practice would lead to improved efficacy of IFN-beta treatment for the benefit of patients with MS.

Pharmacokinetics and pharmacodynamics of the interferon-betas, glatiramer acetate, and mitoxantrone in multiple sclerosis

Five disease-modifying agents are currently approved for long-term treatment of multiple sclerosis (MS), namely three interferon-beta preparations, glatiramer acetate, and mitoxantrone(1). Pharmacokinetics describes the fate of drugs in the human body by studying their absorption, distribution, metabolism and excretion. Pharmacodynamics is dedicated to the mechanisms of action of drugs. The understanding of the pharmacokinetics and pharmacodynamics of the approved disease-modifying agents against MS is of importance as it might contribute to the development of future derivatives with a potentially higher efficacy and a more favourable safety profile. This article reviews data thus far present both on the pharmacokinetics as well as on the putative mechanisms of action of the interferon-betas, glatiramer acetate, and mitoxantrone in the immunopathogenesis of MS.

Fortschritte im Verständnis von Pathogenese und Immuntherapie der Multiplen Sklerose

In this article recent advances in research on the pathogenesis of multiple sclerosis (MS) are summarized. New evidence from molecular histopathology is discussed focussing on neurodegenerative aspects. In addition findings with a direct effect on therapeutic decisions are presented which have contributed to improved immunotherapy. During the last decade important advances in immunotherapy have proven especially useful for patients with relapsing-remitting MS. Escalating algorithms are available for both relapses and long-term immunotherapy. Novel therapeutic approaches with monoclonal antibodies have increasing importance, yet side effects are not completely understood. The pathogenetic insights presented here may open new avenues for novel immunotherapies and lead to individualized MS therapy in the future. Limitations are given for primary progressive MS due to the lack of suitable tissue specimens and experimental models. Neuroprotective treatment strategies aiming at the protection of glial and neuronal cells are still in early stages of development.

Neutralizing antibodies to interferon beta-1b are not associated with disease worsening in multiple sclerosis

The clinical impact of neutralizing antibodies (NAbs) on interferon beta (IFNbeta) efficacy was studied in three large patient cohorts comprising 6698 multiple sclerosis (MS) patients receiving IFNbeta-1b across North America, Europe, and Australia. In North America and Europe, NAb testing was generally undertaken because of a poor clinical response; in Australia, it was mandatory for every patient. Of the 6697 patients tested, 28.9% had at least one NAb titre > or = 20 neutralizing units (NU)/ml, 14.4% had NAb titres > or = 100 NU/ml and 7.7% had NAb titres > or = 400 NU/ml. The NAb-positive rate of 37.0% in Australia was significantly greater than those in North America (21.3%) and Europe (27.6%), and this was observed at every NAb titre level. Our results suggest that NAbs are not responsible for poor clinical responses and that NAb status is of little clinical value. These findings will need to be confirmed in a large independent study.

The safety and efficacy of IFN-beta products for the treatment of multiple sclerosis

Multiple sclerosis, a chronic demyelinating disease of the CNS, is now a treatable disease. Phase III clinical trials of three recombinant IFN-beta products conducted in relapsing-remitting multiple sclerosis have shown, albeit modest, significant effects on relapses and short-term progression of disability, and a more substantial effect on MRI parameters. However, these effects do not correlate well with clinical disease activity or long-term disability. Overall, IFN-beta is safe and generally well tolerated, and reported adverse events were comparable between preparations. Systemic side effects can be effectively managed by dose escalation, use of an auto-injector and careful clinical monitoring.

Control of multiple sclerosis relapses with immunomodulating agents

Relapses in multiple sclerosis (MS) have wide-ranging consequences for patients and should be actively controlled with an appropriate immunomodulating agent provided soon after the diagnosis of MS. Several agents with varying mechanisms of action are approved for use in treating MS. Here we take a brief look at several short- and long-term comparative trials, examining the established strengths and weaknesses of the available immunomodulators. By reviewing the existing comparisons, clinicians will better understand the factors determining when to initiate therapy with an immunomodulator and how to determine which of these treatments may best suit their patients' needs.

Neutralising antibodies to interferon β in multiple sclerosis

Interferon beta (IFNbeta) therapy for multiple sclerosis (MS) is associated with a potential for the development of neutralising antibodies (NAbs) that negatively affect therapy. Several factors influence the development of NAbs, such as lack of complete sequence homology with the endogenous IFNbeta sequence, frequency of administration, level of dose and formulation of IFNbeta. Taken together, the evidence that NAb status reduces clinical efficacy in MS patients is strong. Standardised assays for NAbs are lacking, and titres vary over time. NAb testing is a critical component of care for MS patients because it provides information on one of the most important factors determining clinical responsiveness to IFNbeta therapy. This expert panel report attempts to move the field towards resolution of the remaining issues and considers several aspects of NAbs, including their clinical relevance, factors influencing immunogenicity, assays to quantify NAbs and the definition of clinically relevant titres.

Interferon-β1afor the treatment of multiple sclerosis

At present, two types of recombinant human interferon (IFN)-beta are in clinical use. IFN-beta1a is produced in genetically engineered Chinese hamster ovary cells, and its amino acid sequence and glycosylation pattern are identical to those of endogenous human IFN-beta. The beneficial effect of IFN-beta in multiple sclerosis (MS) probably results from different mechanisms of action, such as a direct effect on plasma cells modulating IgG synthesis, an increase of interleukin (IL)-10 levels, the inhibition of IL-1beta and tumour necrosis factor alpha, the stimulation of IL-1 receptor antagonist production, the inhibition of proliferation of leukocytes, a decreased antigen presentation in microglia, a reduction of T cell migration into the brain by inhibition of the activity of T cell matrix metalloproteinases, and a downregulation of adhesion molecules. IFN-beta1a has been shown by several multicenter controlled trials to be effective in relapsing-remitting MS. It reduces relapse rate by 30-50%, magnetic resonance imaging signs of disease activity in 30-80% and disability progression by 30%. It is also effective in preventing conversion to clinically definite MS when given at the time of a first demyelinating event (i.e., at the very beginning of the clinical disease). No clear evidence of the persistence of the efficacy over the long-term has stood out from a systematic analysis of published trials. A Cochrane review concluded that, in fact, the clinical effect beyond the first year of treatment is not clear. Finally, no efficacy has been shown in secondary progressive or primary progressive MS. However, IFN-beta1a is very well tolerated and the most frequent side effects are mild (local skin reaction and flu-like symptoms) and decline in frequency or disappear after the first 3-6 months of treatment. Although the optimal frequency between once weekly or multiple weekly administrations is still controversial, all protocols require multiple monthly injections. Some patients might find it hard to cope with such a treatment regimen over the long term. Ongoing trials with new powerful immunomodulatory drugs, such as monoclonal antibodies, that require only monthly or bimonthly parenteral administrations will probably offer a better tolerated treatment option in the near future.

Measuring and management of anti-interferon beta antibodies in subjects with multiple sclerosis

Interferon Beta is well established as a first line agent to treat relapsing remitting Multiple Sclerosis. It frequently induces the formation of neutralising anti-Interferon Beta Antibodies (Nabs) which may abrogate the clinical efficacy of the drug. Numerous studies have shown a loss of bioactivity of the drug in the presence of Nabs. The focus has shifted to reliable quantification of Nabs and their appropriate incorporation into clinical practice. Here we review the development and persistence of Nabs, the effect on Interferon beta bioactivity, clinical and para-clinical autocome measures in trials, Nab assays and discuss management strategies to optimise the use of Interferon beta in relapsing remitting MS.

I nterferon beta-1a slows progression of brain atrophy in relapsing-remitting multiple sclerosis predominantly by reducing gray matter atrophy

Background Brain atrophy, as assessed by magnetic resonance imaging (MRI), has been correlated with disability in patients with multiple sclerosis (MS). Recent evidence indicates that both white matter (WM) and gray matter (GM) are subject to atrophy in patients with MS. Although neurological deficiencies in MS are primarily due to loss of WM, the clinical significance of GM atrophy has not been fully explored in MS.

Methods We have undertaken a three-year, open-label study, comparing 26 patients who elected to receive intramuscular interferon beta-1a (IFN β-1a) therapy, with 28 patients who elected not to receive therapy. Both groups had quantitative cranial MRI scans at study entry and after three years, and standardized clinical assessments every six months. Brain parenchymal fraction (BPF), GM fraction (GMF), and WM fraction (WMF) percent changes were calculated, and T2- and T1-lesion volumes (LVs) assessed.

Results After three years, mean percent (%) change in BPF favored the IFN β-1a treatment group (IFN β-1a —1.3% versus the control group —2.5%, P=0.009), as did the mean percent change in GMF (+0.2 versus —1.4%, P=0.014), and the mean percent change in T1-LV (—9.3 versus +91.6%, P=0.011). At the end of the study, there was a significant within-patient decrease in BPF for both groups (P=0.02 for the IFN β-1a treatment group, and P<0.001 for the control group), a significant within-patient decrease in WMF for the IFN β-1a treatment group (P=0.01), and a significant decrease in GMF for the control group (P=0.013) when compared with baseline.

Conclusion Over a three-year period, treatment with IFN β-1a significantly slowed the progression of whole-brain and GM atrophy, and of T1-hypointense LV accumulation, when compared with the control group. Multiple Sclerosis 2007; 13: 490-501. http://msj.sagepub.com

Are ex vivo neutralising antibodies against IFN-beta always detrimental to therapeutic efficacy in multiple sclerosis?

Neutralising antibodies (NAbs) against interferon (IFN)-beta reduce the treatment effect in multiple sclerosis (MS). However, data from pivotal trials of IFN-beta in MS suggest that NAb-positive patients may have a reduced relapse rate during the first six to 12 months of therapy. We collected clinical data and plasma samples for NAb measurements prospectively, every six months, in 468 patients treated with the same IFN-beta preparation for at least 24 months. NAbs were measured blindly with a cytopathic effect (CPE) assay. During treatment months 0-6, patients who became NAb-positive had significantly fewer relapses compared to patients who maintained the NAb-negative status, whereas the opposite was observed after month 6. This is in accordance with observations in randomised studies of the three different IFN-beta preparations, showing that patients who become NAb-positive have lower relapse rates during the first six or 12 months of therapy. We hypothesise that low affinity NAbs, present early after the start of IFN-beta therapy, though neutralising in vitro in sensitive assays increase the half-life of IFN-beta in vivo and, thereby, enhance the therapeutic effect. With affinity maturation, NAbs effectively prevent IFN-beta binding to its receptors also in vivo and, hence, abolish the treatment effect.

Immunmodulatorische Stufentherapie der Multiplen Sklerose

The updated recommendations presented here reflect new developments in the diagnostic work-up and immunotherapy of multiple sclerosis (MS) as well as optimization of medical care for MS patients. Monoclonal antibodies provide considerable improvement of treatment, but their use in basic therapy is restricted by their side effect profile. Thus, for the time being, natalizumab is only approved for monotherapy after basic treatment has failed or for rapidly progressive relapsing-remitting MS. In contrast, long-term data on recombinant beta-interferons and glatiramer acetate (Copaxone) show that even after several years no unexpected side effects occur and that a prolonged therapeutic effect can be assumed which correlates with the dose or frequency of treatment. Recently IFN-beta1b (Betaferon) was approved for prophylactic treatment after the first attack (clinically isolated syndrome, CIS). During treatment with beta-interferons, neutralizing antibodies can emerge with possible loss of effectivity. In contrast, antibodies play no role in treatment with glatiramer acetate. During or after therapy with mitoxantrone, serious side effects (cardiomyopathy, acute myeloid leukemia) appeared in 0.2-0.4% of cases. Plasmapheresis is limited to individual curative attempts in escalating therapy of a severe attack. According to the revised McDonald criteria, the diagnosis of MS can be made as early as the occurrence of the first attack (CIS). Recommendations for optimized care of MS patients are also new, thus implementing a resolution of the European Parliament.

Drug Insight: interferon treatment in multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of the CNS. Between 1987 and 1997, clinical trials of three preparations of recombinant interferon-beta were conducted in patients with MS, ushering in a new therapeutic era. These medications have demonstrable benefits and seem to be safe; they represent an important advance in MS treatment. All three formulations of interferon-beta had modest effects on relapses and short-term progression of disability, but the effects on MRI lesion parameters were more substantial. The benefits were greater in clinically isolated syndromes and relapsing-remitting MS than in secondary progressive MS. Although these drugs have been shown to be effective, however, their long-term impact on clinically relevant disability progression is uncertain, and there are many areas of controversy in the MS field regarding the use of these products. There is still a need for more effective treatments, which might include new agents or combination therapies.

Long-term clinical experience with weekly interferon beta-1a in relapsing multiple sclerosis

Post-marketing surveillance studies are needed to assess the long-term safety, compliance and clinical efficacy of interferon beta-1a (IFNbeta-1a) therapy in multiple sclerosis (MS) patients. The goals of this study were to (i) assess the safety, compliance and clinical efficacy of long-term intramuscular (i.m.) IFNbeta-1a therapy in a large cohort of patients, and (ii) suggest possible predictors of therapeutic response. A total of 255 patients were included in the study. Mean time on therapy was 31.7 +/- 19.3 months. Within 3 years, 31% of patients discontinued treatment, mainly for disease activity. No significant sustained blood analysis alteration was observed over time, apart from a decrease of cholesterol levels. After 3 years of treatment, mean Expanded Disability Status Scale (EDSS) scores increased by 0.4 points compared with baseline. The mean annual relapse rate was reduced compared with baseline. Patients with < or = 2 relapses in the previous 2 years and with baseline EDSS scores of < or = 2 had a longer estimated time to first relapse and to progression and first relapse, respectively. These results confirm the safety and suggest a sustained effectiveness of i.m. IFNbeta-1a, extending the reported follow-up period to 6.3 years, and hypothesize the presence of possible predictors of clinical outcome.

Neutralising antibodies to IFN-β in patients with multiple sclerosis

The development of neutralising antibodies (NABs), or neutralising activity in the absence of NABs, is a potential complication of therapy with interferon (IFN)-beta for patients with multiple sclerosis, limiting therapeutic efficacy. Discontinuation of IFN-beta therapy in patients found to have sustained titres of NABs > 1:100 over an interval of 3 - 6 months has been recently proposed as a Level A recommendation. The extent to which NABs are causative, rather than an epiphenomenon, in determining drug failure has been a matter of numerous investigations and is still controversial. Thus, further studies are warranted for determining the role that NABs may play in reducing the response to the drug. In particular, the effects of NABs in reducing the efficacy of IFN-beta therapy beyond clinical relapse rate and lesion load on conventional imaging are not as yet fully understood.

A recommended treatment algorithm in relapsing multiple sclerosis: report of an international consensus meeting

An International Working Group for Treatment Optimization in MS met to recommend evidence-based therapeutic options for the management of suboptimal responses or intolerable side-effects in patients treated with disease-modifying drugs (DMDs) for multiple sclerosis (MS). Several DMDs are now available for the treatment of MS that have been shown to alter the clinical course of the disease by decreasing disease activity and delaying the progression of disability. Nevertheless, many patients continue to experience disease activity whilst on treatment, and recommendations have been made on how the success of therapy in an individual patient can be assessed. However, even after having identified criteria for a suboptimal response to current treatments, clinicians require guidance on how to improve the outcomes. This report summarizes the conclusions from a workshop at which this issue was addressed. We suggest treatment pathways for optimizing therapy for those patients with suboptimal responses to DMDs, and therapeutic options for patients with unacceptable side-effects on their current therapy.

Natalizumab plus interferon beta-1a for relapsing multiple sclerosis

BACKGROUND

Interferon beta is used to modify the course of relapsing multiple sclerosis. Despite interferon beta therapy, many patients have relapses. Natalizumab, an alpha4 integrin antagonist, appeared to be safe and effective alone and when added to interferon beta-1a in preliminary studies.

METHODS

We randomly assigned 1171 patients who, despite interferon beta-1a therapy, had had at least one relapse during the 12-month period before randomization to receive continued interferon beta-1a in combination with 300 mg of natalizumab (589 patients) or placebo (582 patients) intravenously every 4 weeks for up to 116 weeks. The primary end points were the rate of clinical relapse at 1 year and the cumulative probability of disability progression sustained for 12 weeks, as measured by the Expanded Disability Status Scale, at 2 years.

RESULTS

Combination therapy resulted in a 24 percent reduction in the relative risk of sustained disability progression (hazard ratio, 0.76; 95 percent confidence interval, 0.61 to 0.96; P=0.02). Kaplan-Meier estimates of the cumulative probability of progression at two years were 23 percent with combination therapy and 29 percent with interferon beta-1a alone. Combination therapy was associated with a lower annualized rate of relapse over a two-year period than was interferon beta-1a alone (0.34 vs. 0.75, P<0.001) and with fewer new or enlarging lesions on T(2)-weighted magnetic resonance imaging (0.9 vs. 5.4, P<0.001). Adverse events associated with combination therapy were anxiety, pharyngitis, sinus congestion, and peripheral edema. Two cases of progressive multifocal leukoencephalopathy, one of which was fatal, were diagnosed in natalizumab-treated patients.

CONCLUSIONS

Natalizumab added to interferon beta-1a was significantly more effective than interferon beta-1a alone in patients with relapsing multiple sclerosis. Additional research is needed to elucidate the benefits and risks of this combination treatment. (ClinicalTrials.gov number, NCT00030966.).

Étude observationnelle de la mitoxantrone dans les formes rémittentes actives de sclérose en plaques: suivi à long terme d’une cohorte de 100 patients consécutifs

INTRODUCTION

On the basis of the French and British (FB) MS Trial, Mitoxantrone (MITOX) was approved by the AFSAPPS in October 2003 in patients with aggressive multiple sclerosis (MS), given as induction therapy monthly for 6 months (ELSEP). We report an observational study of 100 aggressive relapsing remitting (RR) MS patients treated by induction therapy with MITOX and followed up to 5 years.

METHODS

One hundred patients with aggressive RR MS received an induction therapy with MITOX 20 mg monthly combined with methylprednisolone 1 g for 6 months. MRI data within 12 months before and 6 months after MITOX induction were collected (mean cumulative dose 65 mg/m2). Clinical evaluation was performed every 6 months and data (relapses and EDSS scores) were prospectively recorded in the EDMUS Database. After MITOX, a maintenance therapy was given to 57 patients (MITOX every 3 months: 21; Interferon beta: 13; Azathioprine: 14; Methotrexate: 7; Glatiramer acetate: 2). The mean follow-up period was of 3.8 years.

RESULTS

Patients were treated at a mean age of 27 +/- 9 years after 5 +/- 3 years of MS duration. Within the 12 months preceding MITOX onset, the annual relapse rate (ARR) was 3.2, the mean EDSS increased by 2.2 +/- 1 points (to a score of 4 at M0), 87 patients worsened by 1 point EDSS or more and 85 percent of patients had Gd enhancing lesions on MRI. During the 12 months following MITOX onset, the inflammatory activity of the disease dropped dramatically with a reduction of the ARR by 91 percent whereas 76 percent of patients were free of new relapse and MRI activity was reduced by 89 percent. In addition, the mean EDSS decreased by 1.2 points (p<10-6) and 60 percent of patients improved by 1 point EDSS or more. At a longer term, the reduction of the ARR was confirmed (0.28-0.37 up to 5 years) and the median time to the first relapse was 2.8 years. A significant improvement of disability was maintained until 4 years and got back to the initial level at year 5. The ARR was significantly lower (0.09) for patients treated with MITOX every 3 months as maintenance therapy than for patients treated by other disease modifying therapies (0.33-0.39) or not (0.43) after the induction. Three patients presented an asymptomatic decrease of the left ventricular ejection fraction under 50 percent, reversible in one case.

CONCLUSION

MITOX as induction therapy monthly for 6 months was safe and had a rapid and strong impact on the inflammatory process and on the evolution of disability. The drug might be a good candidate as induction therapy followed by a maintenance therapy in patients with aggressive MS.

The clinical importance of neutralizing antibodies in relapsing-remitting multiple sclerosis

BACKGROUND

Neutralizing antibodies (NAbs) develop in patients receiving interferon beta (IFN-beta) for multiple sclerosis (MS). Debate continues concerning the relevance of NAb development on treatment efficacy.

OBJECTIVE

To determine the incidence and clinical importance of NAbs in patients with relapsing-remitting MS (RRMS).

METHODS

A comprehensive literature review was conducted using PubMed (accessed from 1983 to June 2005), Cochrane MS Group trials register (accessed June 2005), MEDLINE (accessed 1983 to June 2005), and Toxnet (accessed June 2005) databases. NAb-induced changes in clinical efficacy and disease progression were evaluated according to the clinical guidelines established by the American Academy of Neurology.

RESULTS

Currently, there is no standardized assay to comparatively assess NAbs among different treatments. NAbs develop independent of age, sex, disease duration and progression index at the onset of treatment. The occurrence of NAbs varies from 2-45% depending on the treatment initiated. NAb+ patients demonstrate accelerated disease progression as confirmed by an approximate 1-point increase in the Expanded Disability Status Scale score. The odds of relapse during a NAb+ period are between 1.51 and 1.58 (p < 0.03) with the time to first relapse being shortened by an average of 244 days after 12 months of IFN-beta therapy. NAb+ patients experience an approximately four-fold increase (p = 0.009) in the median number of active T2 magnetic resonance imaging (MRI) lesions compared to NAb-negative patients (1.4 vs. 0.3 respectively, p < 0.01).

CONCLUSION

The induction of NAbs in IFN-beta treated patients reduce clinical effect and accelerate disease progression.