Double blind study of intrathecal beta-interferon in multiple sclerosis: clinical and laboratory results

Revisiting the antiviral theory to explain interferon-beta's effectiveness for relapsing multiple sclerosis

Treatments with interferon-beta (IFNβ) - a cytokine with established antiviral effects - were initially considered for multiple sclerosis (MS), as epidemiological data pointed towards a viral etiological agent for it. Later, when no specific agent was found for MS, theories explaining IFNβ's mechanism of action (MOA) relied on anti-inflammatory mechanisms, which did not explain its ineffectiveness for disease progression independent of relapse activity (PIRA) in progressive forms of MS. Now, with new evidence backing the Epstein-Barr virus (EBV) as a conditional agent in MS etiopathogenesis as well as linking the reactivation of a wide range of other Herpesviridae with MS onset/relapse, it may be time to revisit the antiviral theory to explain IFNβ's MOA, look at the evidence from the past two decades from that perspective, and address the paucity of knowledge with new direct studies and discussions.

Recent developments in interferon-based therapies for multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic and disabling immune-mediated disease of the central nervous system. Beta-interferons are the first approved and still the most widely used first-line disease-modifying treatment in MS.

AREAS COVERED

Here we focus on recent developments in pharmacology and delivery systems of beta-interferons, and discuss their place within current state of the art therapeutic approaches. We briefly review the clinical trials for classical and PEGylated formulations, emphasizing effectiveness, safety concerns, and tolerability. The mechanisms of action of IFN-β in view of MS pathogenesis are also debated

EXPERT OPINION

Though only modestly efficient in reducing the annualized relapse rate, beta-interferons remain a valid first-line option due to their good long-term safety profile and cost-efficacy. Moreover, they are endogenous class II cytokines essential for mounting an effective antiviral response, and they may interact with putative MS triggering factors such as Epstein-Barr virus infection and human endogenous retroviruses. Recent improvements in formulations, delivery devices and drug regimens tackle the tolerability and adherence issues frequently seen with these drugs, and scientific advances may offer means for a better selection of patients. Although a well-established immunomodulatory treatment, beta-interferons have not said their last word in the management of MS.

New insights into an autoimmune mechanism, pharmacological treatment and relationship between multiple sclerosis and inflammatory bowel disease

Inflammatory bowel disease (IBD) and multiple sclerosis (MS) are autoimmune diseases with a close relationship to their disease pattern and immunologic cascade with considerable morbidity and mortality. This article provides insight of why tumor necrosis factor blockers couldn't work in multiple sclerosis and why interferon-beta doesn't work in inflammatory bowel disease. In this article, we provide a detailed review of the linkage and potential interchangeable medication between IBD and MS in addition to Natalizumab, Trichuris suis egg therapy and vitamin D. Different treatment strategies may have potential in treating both diseases in the future.

Acetaminophen modulates the transcriptional response to recombinant interferon-beta

Background

Recombinant interferon treatment can result in several common side effects including fever and injection-site pain. Patients are often advised to use acetaminophen or other over-the-counter pain medications as needed. Little is known regarding the transcriptional changes induced by such co-administration.

Methodology/Principal Findings

We tested whether the administration of acetaminophen causes a change in the response normally induced by interferon-β treatment. CD-1 mice were administered acetaminophen (APAP), interferon-β (IFN-β) or a combination of IFN-β+APAP and liver and serum samples were collected for analysis. Differential gene expression was determined using an Agilent 22 k whole mouse genome microarray. Data were analyzed by several methods including Gene Ontology term clustering and Gene Set Enrichment Analysis. We observed a significant change in the transcription profile of hepatic cells when APAP was co-administered with IFN-β. These transcriptional changes included a marked up-regulation of genes involved in signal transduction and cell differentiation and down-regulation of genes involved in cellular metabolism, trafficking and the IκBK/NF-κB cascade. Additionally, we observed a large decrease in the expression of several IFN-induced genes including Ifit-3, Isg-15, Oasl1, Zbp1 and predicted gene EG634650 at both early and late time points.

Conclusions/Significance

A significant change in the transcriptional response was observed following co-administration of IFN-β+APAP relative to IFN-β treatment alone. These results suggest that administration of acetaminophen has the potential to modify the efficacy of IFN-β treatment.

Interferons: The pathways of discovery

This article analyzes the conceptual and technological context in which, over a period of 50 years, exploration of the biological and clinical significance of type I interferon has evolved. The elaboration of techniques for production and purification of mouse and human interferons and the establishment of laboratory-size production units have been of crucial importance in this process. Animal experiments have been invaluable for elucidation of mechanisms underlying the in vivo antiviral, anti-tumour and immunomodulatory potential of interferon, but have been of limited help to define the areas of clinical applicability. Proof of principle for applications as they are established today has come from clinical trials performed quite independently of evidence from animal experiments.

Interferon- alpha and - beta restrict polyomavirus JC replication in primary human fetal glial cells: implications for progressive multifocal leukoencephalopathy therapy

One of the major limitations of highly active antiretroviral therapy is its inability to inhibit the replication of polyomavirus JC (JCV), the etiologic agent of progressive multifocal leukoencephalopathy (PML), an acquired immunodeficiency syndrome-defining illness. We previously demonstrated the induction of interferon (IFN)-stimulated genes (ISGs) by JCV. In the present study, we characterize the specific viral events required to induce ISGs and the potential antiviral effects of type I IFN on JCV replication in human fetal glial cells in the presence and absence of type I IFNs. Productive JCV replication was essential for the induction of the antiviral host response. JCV replication at all steps was significantly inhibited in the presence of IFN, and neutralizing anti-IFN antibody rescued the inhibitory effect of IFN. These results support the use of IFN as an adjunct therapy for patients with PML. Because IFN cannot cross the blood-brain barrier to achieve its direct antiviral effect, intrathecal administration of IFN is warranted.

Interferons in relapsing remitting multiple sclerosis: a systematic review

BACKGROUND

Recombinant interferons have been approved by many national regulatory agencies for treatment of relapsing remitting multiple sclerosis, but widespread discussion continues about their true effectiveness, benefits, side-effects, and costs.

METHODS

With the Cochrane Collaboration methodology, we reviewed all published, randomised, placebo-controlled trials of recombinant interferons undertaken in patients with relapsing remitting multiple sclerosis between 1993 and 2002. Our primary aim was to find out whether recombinant interferons reduced the number of patients who had clinical exacerbations and disease progression, compared with placebo.

FINDINGS

The seven trials that met our criteria included 1215 randomised patients: data from 667 (55%) were available for analysis at 1 year's and from 919 (76%) at 2 years' follow-up. Interferon seemed to reduce the number of patients who had exacerbations during the first year of treatment (relative risk 0.73, 95% CI 0.54-0.99), but results at 2 years' follow-up were not robust and were difficult to interpret because of the many dropouts. Although the number of patients who had exacerbations (0.81, 0.74-0.89) or progressed (0.70, 0.55-0.88) during the first 2 years fell significantly in the protocol analysis, results were inconclusive after sensitivity analyses for exacerbations (1.11, 0.73-1.68) and disease progression (1.31, 0.60-2.89). Data were insufficient to establish whether steroid use and admissions to hospital were reduced in the interferon group. Similarly, MRI outcome data could not be analysed quantitatively. Side-effects were common, and acute toxic effects adversely affected quality of life.

INTERPRETATION

Recombinant interferons slightly reduce the number of patients who have exacerbations during first year of treatment. Their clinical effect beyond 1 year is uncertain and new trials are needed to assess their long-term effectiveness and side-effects.

Interferon beta-1b and intravenous methylprednisolone promote lesion recovery in multiple sclerosis

OBJECTIVE

To determine whether lesion evolution in relapsing-remitting multiple sclerosis (RRMS) patients is altered by treatment with interferonbeta1b (IFNbeta-1b) or by intravenous methylprednisolone (IVMP) as measured by magnetization transfer imaging.

METHODS

Magnetization transfer ratios (MTR) of 225 contrast enhancing lesions (CEL), in four RRMS patients were serially determined for 12 months before and 12-18 months after contrast enhancement in a baseline vs treatment trial with IFNbeta-1b. During the baseline period, 185 new CEL were identified: 76 were treated with IVMP (1 g/day x 5 days) and designated steroid CEL (S-CEL); the remaining 109 were considered baseline lesions (BCEL). During IFNbeta-1b treatment, 40 CEL (IFN-CEL) were identified. After image co-registration, regions of interest (ROIs) defining new CEL were transferred to the MTR image set to determine the mean lesion MTR on each monthly exam. The lesion MTR was compared to MTR of normal appearing white matter (NAWM) on the same exam.

RESULTS

As early as 12 months prior to enhancement, the MTR of CEL was reduced compared to NAWM (mean 9.43 +/- 3.2%; P<0.001). The further reduction in MTR (28% +/- 4.0) at the time of contrast enhancement was not significantly different for BCEL, S-CEL or IFN-CEL Following enhancement, lesion recovery for IFN-CEL (P=0.02) and S-CEL (P=0.002) was significantly higher than BCEL CONCLUSION: IFNbeta-1b and IVMP reduce tissue damage and promote lesion recovery in RRMS patients. The additional benefit of IVMP compared to IFNbeta-1b may be related to its inhibitory effect on demyelination.

Interferon in relapsing-remitting multiple sclerosis

BACKGROUND

Recombinant interferons have been shown to suppress both the clinical and magnetic resonance imaging (MRI) measures of disease activity in patients with relapsing remitting multiple sclerosis (RRMS).

OBJECTIVES

We performed a Cochrane review of all randomised, placebo-controlled trials of recombinant interferons in RRMS.

SEARCH STRATEGY

Of 208 articles identified by a predefined search strategy, seven of these, reporting randomised trials, met all the selection criteria and form the subject of this review.

SELECTION CRITERIA

The trials selected were double-blind, placebo-controlled, randomised trials of RRMS patients who were treated with recombinant interferon, given by the subcutaneous or the intramuscular route.

DATA COLLECTION AND ANALYSIS

The quality of the trials was variable, with substantial methodological inadequacies in allocation concealment, high proportion and incomplete description of dropouts and failure to adhere to the principles of intention to treat analysis. The baseline characteristics were largely comparable between treatment and placebo groups. Because of prominent treatment-associated side effects, which could be easily identified by patients, these trials could be considered as single blind rather than double-blind.

MAIN RESULTS

Although 1215 patients were included in this review, only 919 (76%) contributed to the results concerning exacerbations and progression of the disease at two years. Specifically interferon significantly reduced the occurrence of exacerbations (RR =0.80, 95% CI [0.73,0.88], p<0.001) and progression of the disease (RR =0.69, 95% CI [0.55,0.87], p= 0.002) two years after randomisation. However, the correct assignment of dropouts was essential to the demonstration of efficacy, most conspicuously concerning the effect of the drug on disease progression. If interferon-treated patients who dropped out were deemed to have progressed (worst case scenario) the significance of these effects was lost (RR = 1.31, CI [0.60,2.89], p = 0.5). The evolution in magnetic resonance imaging (MRI) technology in the decade in which these trials were performed and different reporting of data among trials made it impossible to perform a quantitative analysis of the MRI results. Both clinical and laboratory side effects reported in the trials were more frequent in treated patients than in controls. No information was available regarding side effects and adverse events after two years of follow-up. The impact of interferon treatment (and its side effects) on the quality of life of patients was not reported in any trial included in this review.

REVIEWER'S CONCLUSIONS

The efficacy of interferon on exacerbations and disease progression in patients with relapsing remitting MS was modest after one and two years of treatment. It was not possible to conduct a quantitative analysis beyond two years. Longer follow-up and more uniform reporting of clinical and MRI outcomes among these trials might have allowed for a more convincing conclusion.

Significant correlation between IL-10 levels and IgG indices in the cerebrospinal fluid of patients with multiple sclerosis

We measured the interleukin (IL)-6 and IL-10 levels in the plasma and the cerebrospinal fluid (CSF) of a total of 23 relapsing multiple sclerosis (MS) patients [18 with conventional form of MS (C-MS) and 5 with optic-spinal form of MS (OS-MS)] using ELISA and correlated them with the IgG indices and oligoclonal IgG bands (OB) to determine whether these cytokines play a role in the intrathecal immunoglobulin production. IL-10 values in the CSF significantly correlated with the IgG indices and tended to be higher in OB-positive patients. In contrast, IL-10 values in the plasma and IL-6 values in the CSF and the plasma did not correlate with the IgG indices or OB. The CSF-IL-10 value in OS-MS were much lower than those of C-MS, but those of CSF IL-6 did not differ between C-MS and OS-MS. The results remained unchanged even when OS-MS patients were excluded. Our results may suggest a role of IL-10 in upregulating the intrathecal IgG synthesis in relapsing MS.

Discontinuation of treatment with IFN-beta leads to exacerbation of experimental autoimmune encephalomyelitis in Lewis rats. Rapid reversal of the antiproliferative activity of IFN-beta and excessive expansion of autoreactive T cells as disease promoting mechanisms

IFN-beta has recently been shown to exert remarkable beneficial effects on disease development in patients with early stage relapsing-remitting MS. The specific immune mechanism(s) by which IFN-beta ameliorates this human demyelinating disease is at present undefined. One potential mechanism may reside in the antiproliferative activity of IFN-beta which may inhibit the expansion of autoaggressive T cells thereby limiting disease progression. In the present study we investigated whether the administration of recombinant rat IFN-beta (rrIFN-beta) to Lewis rats with actively induced experimental autoimmune encephalomyelitis (EAE) inhibits the expansion of encephalitogenic T cells in lymphoid organs and as such may contribute to suppression of disease activity in this widely used animal model for MS. Our data show that daily administrations of > or = 3 x 10(5) u rrIFN-beta to EAE rats, starting two days before MBP sensitization and continued for 10 days led to a dramatic and dose-dependent reduction in encephalitogenic T cells in both spleen and inguinal lymph nodes at day 8 post-immunization (p.i.). However, the rrIFN-beta-mediated reduction in effector T cells did not ameliorate paralytic disease as expected but significantly enhanced the severity of EAE. Analyses of lymphoid organs in the remission phase of EAE revealed strongly elevated numbers of encephalitogenic T cells in rrIFN-beta-treated versus control rats suggesting a rapid reversal of the antiproliferative action of rrIFN-beta followed by an overshoot in the subsequent expansion of these effector T cells. In conformity with higher numbers of encephalitogenic T cells and worsening of disease, animals also showed significantly greater perivascular inflammation in the CNS. The relevance of our findings in relation to the beneficial effects of IFN-beta in MS is discussed.

Does a placebo-effect exist in clinical trials on multiple sclerosis? Review of the literature

To verify whether the outcome in placebo-treated MS patients actually corresponds to that expected on the basis of the natural history and pretrial evolution of the disease, we here review the results of clinical trials conducted according to a placebo-controlled, randomized design, regardless of the experimental therapy used. The frequency of relapse in remitting-relapsing patients decreases during follow-up, and disability in progressive cases increases more slowly than before enrollment. These data should be borne in mind when evaluating the impact of experimental drugs on the natural course of the disease.

Interferon beta for multiple sclerosis

OBJECTIVE

To introduce readers to the use of a new agent, interferon beta-1b (IFN beta ser), in the treatment of relapsing-remitting multiple sclerosis (RRMS). Therapeutic and economic issues surrounding IFN beta ser are discussed, as are its pharmacology, clinical efficacy, adverse effects, and dosage guidelines.

DATA SOURCES

A MEDLINE search was used to identify pertinent literature, including clinical trials and reviews.

STUDY SELECTIONS

All available trials were reviewed.

DATA EXTRACTION

Since trials evaluating subcutaneously administered interferon beta are sparse, clinical trials evaluating intrathecal IFN beta ser were included, as was toxicology information from the oncology population.

DATA SYNTHESIS

IFN beta ser has recently been approved by the Food and Drug Administration for the treatment of RRMS. Its exact mechanism of action is unknown, but it may downregulate interferon gamma (IFN gamma) production and the IFN gamma-stimulated major histocompatibility complex antigen expression, and/or augment T-suppressor cell function. Primary adverse effects include flu-like symptoms, fever, chills, myalgia, sweating, and injection-site reactions. Clinical efficacy has been investigated in 372 ambulatory patients with RRMS. IFN beta ser treatment resulted in a reduction in the annual exacerbation rate and a greater proportion of exacerbation-free patients. Burden of central nervous system disease was also significantly reduced in treated patients. However, no reductions were detected on the Scripps Neurologic Rating Scale or with confirmed endpoint scores on the Kurtzke Expanded Disability Status Scale. Although many questions remain concerning IFN beta ser's long-term efficacy, its benefits in patients with other types of multiple sclerosis (MS), and its effect on progression of disease and ultimate disability, IFN beta ser is the first treatment modality that has substantially altered the natural course of MS in a controlled clinical trial.

CONCLUSIONS

IFN beta ser is not a cure for MS, but it is well tolerated and patients with RRMS have shown significant improvements in exacerbation rates and burden of central nervous system disease. IFN beta ser should be considered a definite improvement in RRMS treatment, although many therapeutic issues remain unanswered. Additional clinical trials are needed.

Clinical trials of interferons in multiple sclerosis. What have we learned?

Although multiple sclerosis (MS) is generally believed to be an immune-mediated disease, conventional therapy with ACTH, corticosteroids, or immunosuppressive drugs is unsatisfactory. Aside from their unpredictable therapeutic effects, these agents are potentially hazardous and can only be given for short periods of time. There is an urgent need for less toxic yet effective immunotherapy, that that can be administered early in the disease and continued indefinitely. Clinical trials of the interferons (IFNs) have not only led to a promising new approach to treatment, but have also stimulated basic research in the immunological mechanisms of underlying disease activity. Administration of IFN-gamma promotes exacerbations of MS, whereas recombinant IFN-beta has been shown, in controlled clinical trials, to suppress them. Other ongoing studies are likely to provide further information about its long-term therapeutic value. More importantly, laboratory studies performed in conjunction with these clinical trials have provided fresh insights into the pathogenesis of MS by revealing immunoregulatory mechanisms in which endogenous IFN-gamma, TNF-alpha, and other cytokines appear to play central roles. The 'Decade of the Brain' may therefore see answers both to the therapeutic dilemma of MS, and to more basic questions about the function of IFNs and other cytokines in activation and regulation of the disease process.

The current therapy of multiple sclerosis

The mainstay of treatment for multiple sclerosis in the U.K., and worldwide, remains corticosteroid therapy. High-dose pulses of intravenous methylprednisolone is currently the most favoured agent for acute exacerbations or a sudden acceleration in clinical course. Many patients who follow a more insidious decline rely on symptomatic treatments designed to ameliorate the chronic symptoms associated with their condition. Attempts to influence disease progression using a wide range of immune-modulating agents have not to date been of sufficient clinical benefit to justify their routine usage. With increasing understanding of the underlying disease mechanisms future treatments are being more specifically directed toward disease prevention.

Update on multiple sclerosis therapy

Multiple sclerosis is a demyelinating disorder of the central nervous system characterized by exacerbations and remissions of symptoms. This article deals with symptomatic therapy involving treatment of spasticity, fatigue, neurobehavioral disorders, paroxysmal disorders, pain, bladder dysfunction, and cerebellar dysfunction. This article also reviews immunosuppressive therapies including treatment of acute exacerbations or overall progression of the disorder with resultant accumulation of disability.

Interferons in multiple sclerosis. A review of the evidence

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system, characterised clinically by relapses and remissions, and leading eventually to chronic disability. Despite an enormous amount of research, the cause of MS remains unknown; however, pathological, genetic, and immunological features have been identified that suggest the disease has an autoimmune basis. Accordingly, current therapy of MS includes corticotrophin or corticosteroids for acute exacerbations, and more potent immunosuppressive drugs for severe cases unresponsive to steroids. All of these agents can cause serious adverse reactions. There is an urgent need for immunotherapy that is less toxic, that can be given early and perhaps indefinitely, and that will prevent relapses and progression of the disease. Our current knowledge of the effects of interferons (IFNs) in MS is based on the results of laboratory research and clinical therapeutic trials carried out over the past decade. Existing evidence points to the conclusion that the effects of the IFNs in MS are mediated by immunoregulatory rather than antiviral or nonspecific mechanisms. Administration of IFN gamma increases the exacerbation rate, and IFN gamma as well as other cytokines may be involved in the pathogenesis of MS lesions. In contrast, studies of IFN beta show that it tends to inhibit the activity of IFN gamma and appears to prevent disease activity. Intrathecal administration of IFN beta, although effective, is cumbersome and potentially hazardous. A large multicentre placebo-controlled trial of systemic recombinant IFN beta was recently conducted in the US, and the results of the first 2 years of treatment were considered sufficiently encouraging that an application for licensing was submitted to the Food and Drug Administration in June 1992. If approved, it will be the first new agent licensed for clinical use in MS in over 20 years. The study will continue under double-blind conditions for at least another year, and a second trial of systemic recombinant IFN beta therapy is also in progress. These studies should provide definitive answers to questions about the role of IFNs in the pathogenesis of MS, as well as the place of recombinant IFN beta as an effective therapeutic agent.