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

Guidelines on use of anti-IFN-beta antibody measurements in multiple sclerosis: report of an EFNS Task Force on IFN-beta antibodies in multiple sclerosis

Therapy-induced binding and neutralizing antibodies is a major problem in interferon (IFN)-beta treatment of multiple sclerosis. The objective of this study was to provide guidelines outlining the methods and clinical use of the measurements of binding and neutralizing antibodies. Systematic search of the Medline database for available publications on binding and neutralizing antibodies was undertaken. Appropriate publications were reviewed by one or more of the task force members. Grading of evidence and recommendations was based on consensus by all task force members. Measurements of binding antibodies are recommended for IFN-beta antibody screening before performing a neutralizing antibody (NAB) assay (Level A recommendation). Measurement of NABs should be performed in specialized laboratories with a validated cytopathic effect assay or MxA production assay using serial dilution of the test sera. The NAB titre should be calculated using the Kawade formula (Level A recommendation). Tests for the presence of NABs should be performed in all patients at 12 and 24 months of therapy (Level A recommendation). In patients who remain NAB-negative during this period measurements of NABs can be discontinued (Level B recommendation). In patient with NABs, measurements should be repeated, and therapy with IFN-beta should be discontinued in patients with high titres of NABs sustained at repeated measurements with 3- to 6-month intervals (Level A recommendation).

The importance of maintaining effective therapy in multiple sclerosis

The INCOMIN study (INdependent COMparison of INterferons) lends further support to the growing body of evidence that both dose and frequency of interferon beta (IFNbeta) administration are important in the treatment of multiple sclerosis (MS). High-dose, high-frequency IFNbeta (IFNbeta-1b 250 microg eod sc and IFNbeta-1a 44 microg sc) treatment offers greater therapeutic benefit, in terms of clinical and magnetic resonance imaging (MRI) outcome measures, compared with low-dose, once-weekly administration of IFNbeta. The importance of maintaining the most effective treatment regimen has been shown in another study. The data from this study suggested that patients who have 'stable' disease (i. e. no evidence of clinical or MRI disease activity) during long-term treatment with IFNbeta-1b 250 microg, who are subsequently treated with low-dose, once-weekly IFNbeta-1a 30 microg, are more likely to experience relapses, disease progression or MRI activity compared with those remaining on IFNbeta-1b 250 microg. These data clearly indicate that frequently administered therapy must be maintained to achieve the optimal therapeutic benefit for patients. Those patients who had their IFNbeta-1b 250 microg therapy reduced to low-dose, once-weekly IFNbeta-1a and experienced a resumption of disease activity were returned to their previous regimen. However, after 1 year of additional follow-up, many of these patients still had clinical or MRI signs of disease activity, highlighting further the risks associated with the reduction of IFNbeta dose and frequency of administration. Taking into consideration the evidence supporting the greater efficacy of IFNbeta-1b 250 microg or IFNbeta-1a 44 microg in MS it is of considerable interest to examine whether it is useful to increase the dose of IFNbeta-1b in patients who do not respond satisfactorily to the approved standard dose. This is the rationale for the recently completed OPTIMS (OPTimization of Interferon for MS) study, in which partially responding patients were randomised to IFNbeta-1b 250 or 375 microg every other day. An interim safety analysis of OPTIMS patients has not raised any safety or tolerability concerns. In summary, there is consistent evidence to support the importance of maintaining frequently administered IFNbeta (IFNbeta-1b 250 microg or IFNbeta-1a 44 microg) for the treatment of MS.

Early treatment and dose optimisation

The use of interferon beta (IFNbeta) in the treatment of multiple sclerosis (MS) has not changed greatly since its introduction. However, two new treatment paradigms have recently emerged-initiation of treatment as early in the course of the disease as possible and the use of higher doses with greater frequency to gain maximum therapeutic effect. The rationale for early treatment comes from evidence showing that early and irreversible pathology exists in very early stages of relapsing remitting MS (RRMS) often before significant disability is apparent and continues during remission. In addition, irreversible axonal damage begins early in the course of MS. Two relatively short-term studies indicate that it is possible to delay the onset of MS by early treatment with low-dose IFNbeta-1a. The BENEFIT (BEtaferon/Betaseron in Newly Emerging MS For Initial Treatment) study is being undertaken to investigate whether early intervention with a high-dose and more frequent administration of IFNbeta-1b (250 microg [8 MIU] every other day [eod]) has the ability to affect long-term clinical and magnetic resonance imaging (MRI) outcomes even more favourably. In addition, together with its follow-up study, BENEFIT will address the open question of long-term effects of early treatment on disease progression. Results from the pivotal IFNbeta-1b study, together with data from PRISMS (Prevention of Relapses and Disability by Interferon beta-1a Subcutaneously in Multiple Sclerosis) showed the presence of a dose-response relationship for IFNbeta in the treatment of RRMS. This finding was confirmed by the results of INCOMIN (INdependent COMparison of INterferons) and EVIDENCE (EVidence of Interferon Dose-response: European North American Comparative Efficacy), direct comparative studies of high-dose (250 microg IFNbeta-1b, 44 microg IFNbeta-1a), high-frequency versus lower dose (30 microg IFNbeta-1a) and less frequent IFNbeta regimens. Results from a pilot study in patients with RRMS have indicated that increasing the dose of IFNbeta-1b to 500 microg (16 MIU) had a more pronounced biological effect compared with the standard 250 microg dose. The BEYOND (Betaferon/Betaseron Efficacy Yielding Outcomes of a New Dose) study is being undertaken to investigate whether IFNbeta-1b 500 microg eod is superior to the standard 250 microg eod dose in treatment-naïve patients with RRMS. A third treatment arm will provide a comparison with glatiramer acetate 20mg subcutaneously once daily.

History of modern multiple sclerosis therapy

Although the earliest recorded description of multiple sclerosis (MS) dates back to the 14(th) century, it was not until the latter years of the 20(th) that treatments for this disabling condition were found. However, the "road to success" has not been without hurdles. Trials with both interferon alpha and gamma proved unsuccessful, as did treatment with oral myelin, cladribine, sulfasalazine and inhibitors of tumour necrosis factor. In 1993, interferon beta-1b (IFNbeta-1b) became the first therapy proven to be effective in altering the natural history of relapsing-remitting MS (RRMS). This was followed by successful trials with IFNbeta-1a and glatiramer acetate. In 1998, a European trial showed IFNbeta-1b to be also beneficial in the treatment of secondary progressive MS (SPMS). A similar trial in North America failed to reach its primary endpoint but was effective across secondary endpoints, highlighting how different methodology and patient populations can lead to inconsistent results and, thus, making comparisons across trials difficult. The trend for early intervention in MS with IFNbeta was recently supported by the CHAMPS (Controlled High-risk Avonex MultiPle Sclerosis) and ETOMS (Early Treatment of Multiple Sclerosis) studies using once-weekly IFNbeta-1a. Both trials demonstrated delayed conversion to clinically definite MS in patients with a clinically isolated syndrome and magnetic resonance imaging (MRI) findings suggestive of MS. Two directly comparative trials of high- (250 microg IFNbeta-1b or 44 microg IFNbeta-1a) and low-dose (30 microg IFNbeta-1a) IFNbeta (INCOMIN [INdependent COMparison of INterferons] and EVIDENCE [EVidence of Interferon Dose-response: European North American Comparative Efficacy]) support the superior efficacy of the higher dose and/or more frequent administration for treating RRMS. Since MS entered the treatment era in 1993, therapies for RRMS, SPMS and, more recently, progressive- relapsing MS have been developed. There is now a much better understanding of the pathogenesis of the disease, but new and improved therapeutic approaches are still needed.

Significance of neutralizing antibodies to interferon beta during treatment of multiple sclerosis: expert opinions based on the Proceedings of an International Consensus Conference

On August 30, 2002, an international panel of neurologists who specialize in the treatment of multiple sclerosis (MS) was convened in Paris (France) to discuss the issue of neutralizing antibodies (NAb) to interferon beta (IFN-beta) therapy in patients with MS. The goals of this meeting were to: (i) review the most recent clinical information on NAb, (ii) come to a consensus on the clinical relevance of NAb in the management of patients with MS receiving IFN-beta therapy, and (iii) establish a framework for the development of patient management guidelines based on scientific consensus. The meeting was chaired by Hans-Peter Hartung (Heinrich-Heine University, Düsseldorf, Germany) and Huub Schellekens (Utrecht University, Utrecht, the Netherlands). This article summarizes the opinions of the expert panel on a number of key issues raised at the meeting.

US FDA-approved disease-modifying treatments for multiple sclerosis: review of adverse effect profiles

Several disease-modifying agents (DMAs) are approved for the treatment of multiple sclerosis, including three interferon (IFN)-beta products, glatiramer acetate and mitoxantrone. This article reviews the adverse event profiles of these DMAs based on the pivotal phase III trials, and provides practical guidelines for managing adverse effects. In general, the most common adverse events associated with IFN beta therapy are flu-like symptoms, including fever, chills and myalgias, and headache. The flu-like symptoms typically resolve within 24 hours and may be mitigated by over-the-counter anti-inflammatory agents. Adverse events related to glatiramer acetate therapy include injection-site reactions and a systemic reaction consisting of flushing, chest tightness, palpitation, anxiety or dyspnoea. The systemic reaction is transient (30 seconds to 30 minutes) and self-limited. Mitoxantrone may cause nausea, vomiting, alopecia, amenorrhoea and myelosuppression; isolated cases of acute leukaemia and dose-related cardiotoxicity have been reported in the literature. Longer-term tolerability data on mitoxantrone as a treatment for multiple sclerosis are needed. It is important for physicians to counsel patients on DMA-related adverse effects, most of which are transient and of mild-to-moderate severity. Various strategies that can be employed to prevent or manage these adverse effects and lessen their impact on the patient are discussed.

Interferon-beta1a treatment for multiple sclerosis

Although multiple sclerosis is probably the most common cause of neurologic disability in young adults, the cause is unknown, the prognosis uncertain and available treatments unsatisfactory. Multiple sclerosis is an inflammatory autoimmune disorder of the CNS and the result of both environmental factors and susceptibility genes. The prognosis is difficult or impossible to predict at the time of diagnosis. Treatments that modulate the course of the disease have only recently become available but the long-term aim to prevent disability and promote repair remains distant. Interferon-beta is the most widely used therapy. The efficacy of interferon-beta in the short term is well documented in many large treatment trials, but the treatment effects are only modest and many issues relating to efficacy in the long term are unresolved. These include uncertain benefit on conversion to secondary-progressive multiple sclerosis, the relevance of neutralizing antibodies and the controversial effect on multiple sclerosis-related brain atrophy.

Interferon beta in relapsing–remitting multiple sclerosis

BACKGROUND AND OBJECTIVE

Long-term observational studies may provide additional information about the behaviour of different drugs in the post-marketing period. We present the data of our cohort of relapsing-remitting multiple sclerosis (RRMS) patients treated with interferon beta (IFNbeta).

METHODS

We analysed RRMS patients followed for at least 2 years. From 1995, we initiated therapy with IFNbeta. As they became available, patients were allocated to one of the IFNs at standard doses (IFNbeta-1b, IFNbeta-1a i.m. or IFNbeta-1a s.c.). Each patient was included in a follow-up protocol containing demographic and baseline clinical data.

RESULTS

Between 1995 and 2004, 382 patients have completed at least 2 years of follow-up. Significant differences at entry were observed. Patients on IFNbeta-1b had a higher disease activity and disability at baseline than those on IFNbeta-1a i.m. or IFNbeta-1a s.c. A significant reduction in the relapse rate was observed for the three drugs (70% for IFNbeta-1b, 64% for IFNbeta-1a i.m. and 74% for IFNbeta-1a s.c.). We observed a sustained progression of disability in 11% of patients on IFNbeta-1b, 17% on IFNbeta-1a i.m. and 19% on IFNbeta-1a s.c.; and at four years of follow-up in 24% of patients on IFNbeta-1b, 23% on IFNbeta-1a i.m. and 35% on IFNbeta-1a s.c. No unexpected major adverse events were observed with any of the drugs.

CONCLUSIONS

Interferon beta is safe and well tolerated. The various registered interferon beta drugs provide a comparable efficacy in a large non-selected cohort of RRMS patients.

Escalating immunotherapy of multiple sclerosis--new aspects and practical application

Recent clinical studies in multiple sclerosis (MS) provide new data on the treatment of clinically isolated syndromes, on secondary progression, on direct comparison of immunomodulatory treatments and on dosing issues. All these studies have important implications for the optimized care of MS patients. The multiple sclerosis therapy consensus group (MSTCG) critically evaluated the available data and provides recommendations for the application of immunoprophylactic therapies. Initiation of treatment after the first relapse may be indicated if there is clear evidence on MRI for subclinical dissemination of disease. Recent trials show that the efficacy of interferon beta treatment is more likely if patients in the secondary progressive phase of the disease still have superimposed bouts or other indicators of inflammatory disease activity than without having them. There are now data available, which suggest a possible dose-effect relation for recombinant beta-interferons. These studies have to be interpreted with caution, as some potentially important issues in the design of these studies (e. g. maintenance of blinding in the clinical part of the study) were not adequately addressed. A meta-analysis of selected interferon trials has been published challenging the value of recombinant IFN beta in MS. The pitfalls of that report are discussed in the present review as are other issues relevant to treatment including the new definition of MS, the problem of treatment failure and the impact of cost-effectiveness analyses. The MSTCG panel recommends that the new diagnostic criteria proposed by McDonald et al. should be applied if immunoprophylactic treatment is being considered. The use of standardized clinical documentation is now generally proposed to facilitate the systematic evaluation of individual patients over time and to allow retrospective evaluations in different patient cohorts. This in turn may help in formulating recommendations for the application of innovative products to patients and to health care providers. Moreover, in long-term treated patients, secondary treatment failure should be identified by pre-planned follow-up examinations, and other treatment options should then be considered.

Randomized study of once-weekly interferon beta-1la therapy in relapsing multiple sclerosis: three-year data from the OWIMS study

BACKGROUND

Once weekly interferon beta-1a for multiple sclerosis (OWIMS) demonstrated modest, but significant, magnetic resonance imaging (MRI) benefit of once-weekly (qw) interferon (IFN) beta-1a at 48 weeks, but no significant effect on relapses.

OBJECTIVE

An OWIMS extension permitted assessment of longer-term efficacy/safety of qw IFN beta-1a in relapsing-remitting multiple sclerosis (RRMS).

METHODS

Placebo patients were rerandomized to IFN beta-1a, 22 or 44 mcg qw, for two additional 48-week intervals. Primary outcome was MRI lesion activity. Relapse rate and other MRI measures were secondary outcomes.

RESULTS

After three years, median (mean) T2 lesion count/patient/scan was 1.3 (2.6) for 44 mcg, 1.7 (3.3) for 22 mcg, 1.7 (3.4) for placebo/22 mcg, 2.0 (3.6) for placebo/44 mcg (all differences not significant). Annualized relapse rates were lowest for 44 mcg (0.77) versus other groups (0.83-0.86, not significant). Persistent neutralizing antibodies did not affect relapse rates, but MRI active lesions were increased in antibody-positive patients receiving 44 mcg compared to antibody negative patients.

CONCLUSIONS

In RRMS, once weekly IFN beta-1a, particularly 44 mcg, can induce a significant MRI, but not relapse, effect, compared with placebo. No significant dose effect was seen. In contrast to the significant effect observed with three-times-weekly dosing of subcutaneous IFN beta-1a compared with placebo, this study confirms the lack of meaningful clinical benefit with once-weekly dosing.

Interferons in relapsing-remitting multiple sclerosis: are there benefits from long-term use?

Multiple sclerosis (MS) is one of the most common chronic neurological diseases in young adults in western countries. An important aspect of treatment of this disease is the use of interferons (IFNs). These are molecules with antiviral, immunomodulatory, antiproliferative and hormonal activities. IFNbeta, a class I IFN, has been used extensively in the therapy of MS, particularly in its relapsing-remitting (RRMS) phase, the most frequent clinical form of the disease. Although the available evidence from published clinical trials is difficult to evaluate because of methodological differences, an unbiased review of the data reveals sufficient evidence to conclude that treatment with IFNbeta in RRMS is both efficacious and safe, at least over the periods so far investigated (up to 4-6 years). While there is no reason to suspect that IFNbeta should not continue to be efficacious and safe over the longer term, studies investigating these questions over longer periods and including greater numbers of patients are needed.

An open-label safety and drug interaction study of natalizumab (Antegren) in combination with interferon-beta (Avonex) in patients with multiple sclerosis

In this open-label drug-interaction trial, we studied 38 patients with relapsing-remitting multiple sclerosis (MS) who received 3.0 or 6.0 mg/kg of natalizumab as a single intravenous (i.v.) infusion during stable treatment with intramuscular (i.m.) interferon beta-1a 30 microg (IFNbeta-1a; Avonex). To assess the pharmacokinetic (PK) interaction of natalizumab and IFNbeta-1a, serum concentration-time data for both agents were collected and analysed. Biologic response markers of IFNbeta-1a activity, beta2-microglobulin and neopterin, were also assessed to determine effects of natalizumab on IFNbeta-1a pharmacodynamics (PD). Further, safety and immunogenicity were evaluated. The combination of drug therapies was well tolerated. Although natalizumab serum concentrations (and corresponding PK exposure measures) appeared to be somewhat elevated in the presence of IFNbeta-1a, when compared to the same dose (6.0 mg/kg) administered alone in a concurrent comparator study, the differences were generally small and unlikely to be clinically relevant. In general, natalizumab had no apparent clinically relevant effects on the PK or PD properties of IFNbeta-1a. The presence of antibodies to IFNbeta-1a and natalizumab was relatively low. Overall, the study provided safety, immunogenicity, PK and PD data to support a combination strategy for the use of natalizumab and IFNbeta-1a in the treatment of patients with relapsing-remitting MS. A large clinical study is currently in progress to evaluate the efficacy and long-term safety of this combination drug therapy.

The pros and cons of early treatment of relapsing forms of multiple sclerosis

Cerebral axonal damage and brain atrophy begin at the earliest stages of multiple sclerosis (MS). Progressive neuronal degeneration contributes to irreversible neurological deficit, and ultimately disability. Axonal loss, which seems to be related to the inflammatory process, occurs much more rapidly in the early than later phases of disease, providing additional impetus for early intervention. The CHAMPS (Controlled High risk Avonex MultiPle Sclerosis) and ETOMS (Early Treatment Of MS) studies show that fewer patients with a first demyelinating event and abnormal magnetic resonance imaging (MRI) had a second clinical attack within 2 years if once-weekly treatment with interferon beta-1a was started at the time of the first episode. However, these studies provide no information on long-term outcomes. The BENEFIT study (BEtaferon/betaseron in Newly Emerging multiple sclerosis For Initial Treatment) will evaluate the efficacy and tolerability of 250 micro g (8 MIU) interferon beta-1b administered every other day to patients with a first demyelinating event suggestive of MS. This study should add some information about some of the outstanding questions relating to the long-term effects of early treatment on disease course, although it is likely that further investigation will be needed before a definite picture can be obtained.

Comparative tolerance of IFN beta-1a regimens in patients with relapsing multiple sclerosis

The EVIDENCE study was a direct comparative study of two dose regimens of interferon (IFN) beta-1a used in the treatment of relapsing-remitting multiple sclerosis (RRMS): 30 mcg intramuscularly once weekly (qw; n=338) and 44 mcg subcutaneously three times weekly (tiw; n=339). The study continued for an average of 64 weeks. The safety population consisted of all patients receiving at least one dose of study drug. Clinical assessments occurred every 4 weeks for 24 weeks and then every 12 weeks. Blood tests for safety were taken at baseline and at weeks 4 and 12, and every 12 weeks thereafter. Overall adverse events were more common with the 44 mcg tiw regimen (p=0.007), and were due predominantly to differences in injection-site reactions. The majority of adverse events were rated mild by investigators. Hepatic and haematological adverse events and asymptomatic laboratory abnormalities were more common with 44 mcg tiw (p<0.001),with no difference seen for severe events. Flu-like symptoms were more common with 30 mcg qw (p=0.031), were more severe and persisted for longer. Serious adverse events were comparable for both groups, as were drug discontinuations. In conclusion, although adverse events were more common with high-dose, high-frequency IFN therapy, differences were primarily for mild events and did not affect treatment adherence. Based on superior clinical and magnetic resonance imaging outcomes over an average of 64 weeks, coupled with modest safety differences, the risk-benefit ratio for IFN therapy in RRMS favours the 44 mcg tiw regimen over this period of time.

Biological responsiveness to first injections of interferon-beta in patients with multiple sclerosis

This study is the first to evaluate biological response to first injections of interferon-beta (IFNbeta) in patients with multiple sclerosis. MxA mRNA was measured in 96 patients receiving IFNbeta-1a (Avonex, n=32), IFNbeta-1b (Betaferon, n=19), IFNbeta-1a (Rebif) 22 microg (n=30), or IFNbeta-1a 44 microg (n=15). Patients were analysed before, 3 and 24 h after the first injection, and 12 h after the second administration. Results showed that up-regulation was evident within 3 h of IFNbeta injection, peaked 12 h after injection, and progressively declined 24 h after administration. The cumulative responses were similar after a single administration, regardless of product/dose. Moreover, data indicate that the abolition of the biological activity detected during IFNbeta therapy is due to underlying phenomena (e.g., neutralizing antibodies), because all patients were constitutively responders to IFNbeta at treatment initiation.

Short-term brain atrophy changes in relapsing–remitting multiple sclerosis

The objective of this study was to establish whether the time interval of 3 months is sufficient to detect whole-brain atrophy changes in patients with relapsing-remitting (RR) multiple sclerosis (MS). Another aim was to assess the value of monthly gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) and of different Gd-enhancement patterns as predictors of brain atrophy. Thirty patients with RRMS (mean disease duration 4.9 years, mean age 34.4 years and mean Expanded Disability Status Scale [EDSS] 1.4) were assessed at baseline and monthly for a period of 3 months with clinical and MRI examinations. Calculations of baseline and monthly absolute and percent changes of MRI measures have been obtained using two semiautomated (Buffalo and Trieste) and one automated (SPM99) segmentation method. Changes of brain parenchymal fraction (BPF) were investigated according to Gd-enhancement patterns. Mean absolute and percent changes of BPF did not significantly differ at any time point in the study for any of the three methods. There was slight but not significant decrease of BPF from baseline to month 3: -0.0004 (0.05%), p=0.093 for Trieste; -0.0006 (0.07%), p=0.078 for Buffalo; and -0.0006 (0.08%), p=0.081 for SPM99 method. In ring-enhancement positive patients, there was a significant difference between baseline and month 3 changes of BPF, EDSS, and number of relapses. Over the study period, we did not demonstrate differences between changes of BPF according to the presence of Gd enhancement. Longitudinally, multiple regression analysis demonstrated that the only clinical or MRI parameter that predicted BPF decrease was the mean absolute change of ring-enhancing lesion load (R=0.62, p=0.003). The noteworthy findings of this study are (1) the observation that a significant brain atrophy progression cannot be detected over a 3-month period in RRMS; (2) the demonstration that the ring-enhancement pattern may contribute to more severe brain tissue loss in the short term; and (3) the lack of relationship between the presence and duration of Gd-enhancement activity and brain volume changes in the short term.

Multicentre, randomised, double blind, placebo controlled, phase III study of weekly, low dose, subcutaneous interferon beta-1a in secondary progressive multiple sclerosis

OBJECTIVE

Interferon (IFN) beta has repeatedly shown benefit in multiple sclerosis (MS) in reducing the rate of relapse, the disease activity as shown with magnetic resonance imaging and, to some degree, the progression of disability; however, it is unknown how much the therapeutic response depends on the dose, the subgroup involved, and the disease stage. This multicentre, double blind, placebo controlled study explored the dose-response curve by examining the clinical benefit of low dose IFN beta-1a (Rebif), 22 micro g subcutaneously once weekly, in patients with secondary progressive MS.

METHODS

A total of 371 patients with clinically definite SPMS were randomised to receive either placebo or subcutaneous IFN beta-1a, 22 micro g once weekly, for 3 years. Clinical assessments were performed every 6 months. The primary outcome was time to sustained disability, as defined by time to first confirmed 1.0 point increase on the Expanded Disability Status Scale (EDSS). Secondary outcomes included a sensitive disability measure and relapse rate.

RESULTS

Treatment had no beneficial effect on time to confirmed progression on either the EDSS (hazard ratio (HR) = 1.13; 95% confidence interval (CI) 0.82 to 1.57; p = 0.45 for 22 micro g v placebo) or the Regional Functional Status Scale (HR = 0.93; 95% CI 0.68 to 1.28; p = 0.67). Other disability measures were also not significantly affected by treatment. Annual relapse rate was 0.27 with placebo and 0.25 with IFN (rate ratio = 0.90; 95% CI 0.64 to 1.27; p = 0.55). The drug was well tolerated with no new safety concerns identified. No significant gender differences were noted.

CONCLUSIONS

This patient population was less clinically active than SPMS populations studied in other trials. Treatment with low dose, IFN beta-1a (Rebif) once weekly did not show any benefit in this study for either disability or relapse outcomes, including a subgroup with preceding relapses. These results add a point at one extreme of the dose-response spectrum of IFN beta therapy in MS, indicating that relapses in this phase may need treatment with higher doses than in the initial phases.

Pharmacological methods to overcome IFN-beta antibody formation in the treatment of multiple sclerosis

Diminished efficacy in terms of clinical relapses and lesion load on magnetic resonance images for patients developing neutralising antibodies (NAbs) to recombinant IFN-beta may be found in multiple sclerosis. NAbs become detectable over the first few years of therapy, disappearing during the treatment course in some patients and persisting longer in some others. Therefore, the administration of concomitant therapies to recombinant IFNbeta to prevent the formation of NAbs could be indicated mainly in the latter group of patients at the early stage of the treatment. Among those therapies, steroids meet the best criteria in terms of either safety or impact on the development of NAbs, at the present time.

Disease-modifying therapies in multiple sclerosis: an update on recent and ongoing trials and future strategies

Multiple sclerosis (MS) is the prototype inflammatory autoimmune disorder of the central nervous system and the most common cause of neurological disability in young adults exhibiting considerable clinical, radiological and pathological heterogeneity. Novel insights in the immunopathological processes, advances in biotechnology, development of powerful magnetic resonance imaging technologies together with improvements in clinical trial design led to a variety of evaluable therapeutic approaches. Therapy has changed dramatically over the past decade, yielding significant progress for the treatment of relapsing-remitting and secondary progressive MS. A substantial number of pivotal and preliminary reports continue to demonstrate encouraging new evidence that advances are being made in the care of MS patients. This review summarises recent progress with currently available disease-modifying therapies and - on the basis of present immunopathogenetic concepts - outlines ongoing studies as well as future treatment strategies.

Dose and Frequency of Administration of Interferon-?? Affect its Efficacy in Multiple Sclerosis

Data reviewed in this article demonstrate that both interferon-beta-1a (IFNbeta-1a) and interferon-beta-1b (IFNbeta-1b) show a dose-response relationship in multiple sclerosis at current clinical doses. Moreover, the efficacy of these therapies is probably dependent on their frequent administration to maintain optimal levels of biological effect. These results differ from the conclusions of a recent review of data comparing two doses of IFNbeta-1a, given intramuscularly once weekly, that showed no difference in efficacy between the two doses. This and other results were interpreted to indicate that the current dose of this product (30microg intramuscularly once weekly) is optimal. However, the data reviewed here indicate that the efficacy of IFNbeta differs depending on the features of the dose regimen, including total dose, route and frequency of administration. Direct comparative data indicate that 44microg given subcutaneously three times weekly is more effective on clinical and magnetic resonance imaging measures, at least up to 48 weeks of therapy, compared with 30microg intramuscularly once weekly; risk-benefit favours 44mug three times weekly over 30mug once weekly.