Randomised controlled trial of methotrexate for chronic inflammatory demyelinating polyradiculoneuropathy (RMC trial): a pilot, multicentre study

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy is a disease causing progressive or relapsing and remitting weakness and numbness. It is probably due to an autoimmune process. Immunosuppressive or immunomodulatory drugs would be expected to be beneficial.

OBJECTIVES

We aimed to review systematically the evidence from randomised trials of cytotoxic drugs and interferons other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Specialised Register (May 2010), The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2), MEDLINE (January 1977 to May 2010), EMBASE (January 1980 to May 2010), CINAHL (January 1982 to May 2010) and LILACS (January 1982 to May 2010). We contacted the authors of the trials identified and other disease experts seeking other published and unpublished trials.

SELECTION CRITERIA

We sought randomised and quasi-randomised trials of all immunosuppressive agents such as azathioprine, cyclophosphamide, methotrexate, ciclosporin A, mycophenolate mofetil, and rituximab and all immunomodulatory agents such as interferon alfa and interferon beta in participants fulfilling standard diagnostic criteria for chronic inflammatory demyelinating polyradiculoneuropathy.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged their methodological quality and extracted data. We wanted to measure the change in disability after one year as our primary outcome. Our secondary outcomes were change in disability after four or more weeks (from randomisation), change in impairment after at least one year, change in maximum motor nerve conduction velocity and compound muscle action potential amplitude after one year and for those participants who were receiving corticosteroids or intravenous immunoglobulin, the amount of this medication given during at least one year after randomisation. Participants with one or more serious adverse events during the first year was also a secondary outcome.

MAIN RESULTS

Four trials fulfilled the selection criteria, one of azathioprine (27 participants), two of interferon beta-1a (77 participants in total) and one of methotrexate (60 participants). None of these trials showed significant benefit in the primary outcome or secondary outcomes selected for this review.

AUTHORS' CONCLUSIONS

The evidence from randomised trials does not show significant benefit from azathioprine, interferon beta-1a or methotrexate but none of the trials was large enough to rule out small or moderate benefit. The evidence from observational studies is insufficient to avoid the need for randomised controlled trials to discover whether these drugs are beneficial. Future trials should have improved designs, more sensitive outcome measures and longer durations.

Can we face the challenge of expanding use of intravenous immunoglobulin in neurology?

The use of high-dose polyclonal intravenous immunoglobulin (IVIG) in the treatment of autoimmune neurological diseases has expanded over the last decade. Based on controlled clinical trials IVIG can be considered currently as the first-line treatment in Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy, and it may be used as a rescue therapy in worsening myasthenia gravis. IVIG is a second-line therapy in dermatomyositis, stiff-person syndrome and pregnancy-associated or postpartum relapses of multiple sclerosis. Although the biological efficacy of IVIG is due to multiple effects on the immune system, many mechanisms are still unknown. The awareness of risks and complications of IVIG therapy has increased, but severe side effects are still considered rare. Due to increasing costs of this treatment, careful selection of patients who will benefit from IVIG is extremely important.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of chronic inflammatory demyelinating polyradiculoneuropathy: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society - first revision

BACKGROUND

Consensus guidelines on the definition, investigation, and treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) have been previously published in European Journal of Neurology and Journal of the Peripheral Nervous System.

OBJECTIVES

To revise these guidelines.

METHODS

Disease experts, including a representative of patients, considered references retrieved from MEDLINE and Cochrane Systematic Reviews published between August 2004 and July 2009 and prepared statements that were agreed in an iterative fashion.

RECOMMENDATIONS

The Task Force agreed on Good Practice Points to define clinical and electrophysiological diagnostic criteria for CIDP with or without concomitant diseases and investigations to be considered. The principal treatment recommendations were: (i) intravenous immunoglobulin (IVIg) (Recommendation Level A) or corticosteroids (Recommendation Level C) should be considered in sensory and motor CIDP; (ii) IVIg should be considered as the initial treatment in pure motor CIDP (Good Practice Point); (iii) if IVIg and corticosteroids are ineffective, plasma exchange (PE) should be considered (Recommendation Level A); (iv) if the response is inadequate or the maintenance doses of the initial treatment are high, combination treatments or adding an immunosuppressant or immunomodulatory drug should be considered (Good Practice Point); (v) symptomatic treatment and multidisciplinary management should be considered (Good Practice Point).

Intravenous immunoglobulin for the treatment of chronic inflammatory demyelinating polyradiculoneuropathy: a systematic review and meta-analysis

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired immune-mediated inflammatory disorder that targets the myelin sheaths of the peripheral nervous system. Intravenous immunoglobulin (IVIg) is a blood product containing immunoglobulin G pooled from many human donors. In fall 2008, CIDP became an approved indication for IVIg in the United States and Canada.

OBJECTIVE

To evaluate the clinical effectiveness and safety of IVIg for the treatment of CIDP through a systematic review of published randomized controlled trials.

METHODS

We searched the MEDLINE (1996-2009, including in-process and other non-indexed citations), Embase (1996-2009) and other databases through the Ovid interface. We applied a methodological filter to limit retrieval to controlled clinical trials, meta-analyses and systematic reviews, and health technology assessments. Retrieval was limited to studies involving humans, and no language restrictions were employed. We pooled extracted data to estimate the effect size of IVIg treatment based on the random-effects model.

RESULTS

We identified 9 unique randomized controlled trials. Of these, 3 compared IVIg therapy with an active comparator (plasma exchange, plasma exchange using extracorporeal immunoadsorption, oral prednisolone, respectively); the other 6 trials had placebo controls. No incremental benefit was seen in terms of primary outcomes for comparisons of IVIg therapy and an active comparator. Data from 4 of the 6 placebo-controlled trials were included in a meta-analysis. A significant improvement in disability (i.e., reduction in disability score) was found, with a standardized mean difference of 0.65 (95% confidence interval [CI] 0.23 to 1.08) in favour of IVIg. A pooled analysis of the proportion of patients with a response to treatment, as defined by the investigators of each of the trials, resulted in a risk ratio of 2.74 (95% CI 1.80 to 4.15) favouring IVIg.

INTERPRETATION

IVIg therapy was statistically superior to placebo in reducing disability and impairment among patients with CIDP. The effectiveness of IVIg was similar to that of the alternative treatment strategies of plasma exchange and oral prednisolone.

Restless legs syndrome in chronic inflammatory demyelinating polyneuropathy

The prevalence of restless legs syndrome (RLS) is unknown in chronic inflammatory demyelinating polyneuropathy (CIDP). We prospectively studied 28 patients with CIDP. Prevalence of RLS in CIDP was ascertained by face-to-face interview using validated criteria and compared with that in 28 age- and gender-matched controls. Eleven (39.3%) CIDP patients were diagnosed with RLS, compared with 2 (7.1%) controls (P < 0.01). A significant correlation was ascertained between presence of RLS and lower limb weakness, functional disability, and summated compound muscle action potential (CMAP). The prevalence of RLS in CIDP was significantly higher than in controls in our study population, approaching 40%. Screening for RLS in CIDP patients may be appropriate, particularly in those with weakness, disability, and motor axonal loss in the lower limbs. Our findings may otherwise suggest the existence of peripheral components to the pathophysiology of RLS in patients with CIDP.

[Advances and perspectives in treatment for refractory neuropathies with special reference to immune-mediated neuropathies and Crow-Fukase syndrome]

There are significant advances in immune-modulating treatments for Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) in the past 20 years. GBS, however, is still a serious disease with a mortality rate of 8% and 20% of the patients being unable to walk independently a year after onset For CIDP and related disorders such as multifocal motor neuropathy, and demyeinating neuropathy with anti-myelin-associated-glycoprotein (MAG) antibody, treatments should be based on individual pathophysiology. Rituximab could be a promising agent for the subtypes of CIDP refractory to conventional immune treatments. Crow-Fukase syndrome is a rare cause of demyelinating neuropathy with multiorgan involvement Overproduction of vascular endothelial growth factor (VEGF), probably mediated by monoclonal proliferation of plasma cells, is likely to be responsible for most of the characteristic symptoms. There is no established treatment regimen for Crow-Fukase syndrome. In appropriate candidates, high-dose chemotherapies with autologous peripheral blood stem cell transplantation is highly recommended, because this treatment could result in obvious improvement in neuropathy as well as other symptoms. Indication of this treatment has not yet been established, and long-term prognosis is unclear at present. Treatments that should be considered as future therapy against Crow-Fukase syndrome include thalidomide, and anti-VEGF monoclonal antibody (bevacizumab).

Treatment in inflammatory neuropathies

This review focuses on recent developments in the treatment of inflammatory neuropathies arising from immune dysregulation, rather than from infectious causes. The dysimmune inflammatory neuropathies are diseases of the peripheral nerves that have varying etiologies and may respond to immunomodulatory therapies. They are characterized by inflammatory changes in the nerve with associated destruction of myelin and axons. The underlying immune mechanisms are better understood in some of these conditions than others. Correct diagnosis and treatment is important to prevent clinical progression. Randomized controlled trials of some treatments in the more common inflammatory neuropathies have clarified their effectiveness; however, there are still groups of patients who are resistant to currently available treatments and for whom little effective treatment is available. Newer, targeted biologics and larger controlled trials of existing and novel therapies in these conditions offer promise of improved morbidity and mortality in this group of diseases.

Chronic inflammatory demyelinating polyradiculoneuropathy: diagnostic and therapeutic challenges for a treatable condition

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic neuropathy of supposed immune origin. Understanding of its pathophysiology has recently improved, although its causes remain unclear. The classic presentation of CIDP includes sensory and motor symptoms in the distal and proximal segments of the four limbs with areflexia, evolving over more than 8 weeks. Raised protein concentrations in CSF and heterogeneous slowing of nerve conduction are typical of the condition. In addition to this usual phenotype, distribution of symptoms, disease course, and disability can be heterogeneous, leading to underdiagnosis of the disorder. Diagnosis is sometimes challenging and can require use of imaging and nerve biopsy. Steroids and intravenous immunoglobulin are effective, and plasma exchange can be helpful as rescue therapy. The usefulness of immunosuppressants needs to be established. The identification of specific diagnostic markers and new therapeutic strategies with conventional or targeted immunotherapy are needed to improve the outlook for patients with CIDP.

Overview of the pathogenesis and treatment of chronic inflammatory demyelinating polyneuropathy with intravenous immunoglobulins

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired heterogeneous disorder of immune origin affecting the peripheral nerves, causing motor weakness and sensory symptoms and signs. The precise pathophysiology of CIDP remains uncertain although B and T cell mechanisms are believed to be implicated. Intravenous immunoglobulins (IVIg) have been shown in a number of trials to be an effective treatment for CIDP. IVIg is thought to exert its immunomodulatory effects by affecting several components of the immune system including B-cells, T-cells, macrophages and complement. This article provides an overview of the pathogenesis of CIDP and of its treatment with IVIg.

Intravenous immunoglobulin for chronic inflammatory demyelinating polyradiculoneuropathy: the ICE trial

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a potentially disabling autoimmune disease causing progressive or relapsing-remitting weakness with or without sensory loss. Previous small trials demonstrated short-term benefit from intravenous immunoglobulin (IVIg), and international guidelines recommend IVIg as an option. However, evidence had been insufficient to persuade authorities to approve IVIg for use in CIDP. This article aims to review the Immune Globulin Intravenous CIDP Efficacy (ICE) trial, which was a randomized, double-blind, placebo-controlled, response-conditional crossover trial of Gamunex (intravenous immunoglobulin, 10% caprylate/chromatography purified). With 117 participants, it is the largest treatment trial ever conducted in CIDP. The results showed unequivocal short- and long-term benefit from IVIg in confirmation of previous reports. The trial also showed for the first time that continued IVIg infusion 1 g/kg every 3 weeks protected participants from relapse. Adverse events were mostly mild and serious adverse events were not more common with IVIg than with placebo. The results persuaded the US FDA and Health Canada to approve Gamunex for use in CIDP.

Plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy is an uncommon progressive or relapsing paralysing disease caused by inflammation of the peripheral nerves. If the hypothesis that it is due to autoimmunity is correct, removal of autoantibodies in the blood by plasma exchange should be beneficial.

OBJECTIVES

To evaluate the efficacy of plasma exchange in chronic inflammatory demyelinating polyradiculoneuropathy.

SEARCH STRATEGY

We searched the Neuromuscular Disease Group Register (December 2003), and MEDLINE (January 1966 to January 2003), EMBASE (January 1980 to January 2003), CINAHL (January 1982 to December 2002) and LILACS (January 1982 to January 2003). We also scrutinised the bibliographies of the trials, and contacted the trial authors and other disease experts.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials in participants of any age comparing plasma exchange with sham treatment or no treatment. A trial showing no significant difference in the benefit from plasma exchange with intravenous immunoglobulin has been included in a separate Cochrane review.

DATA COLLECTION AND ANALYSIS

Two authors selected the trials, extracted the data and assessed methodological quality independently. Where possible data were combined according to the methods of the Cochrane Neuromuscular Disease Review Group.

PRIMARY OUTCOME MEASURE

one crossover trial including 18 participants showed 2 (95% confidence interval (CI) 0.8 to 3.0) points more improvement after four weeks in an 11-point disability scale with plasma exchange (10 exchanges over four weeks) than with sham exchange. Rapid deterioration after plasma exchange occurred in eight of 12 who had improved.

SECONDARY OUTCOME MEASURES

when the results of this trial and another with 29 participants treated in a parallel group design trial were combined, there were 31 points (95% CI 16 to 45) more improvement in an impairment scale after plasma exchange (six exchanges over three weeks) than after sham exchange. There were significant improvements in both trials in an electrophysiological measure, the proximally evoked compound muscle action potential, after three or four weeks. Non-randomised evidence indicates that plasma exchange induces adverse events in 3% to 17% of procedures. These are sometimes serious.

REVIEWERS' CONCLUSIONS

Evidence from two small trials showed that plasma exchange provides significant short-term benefit in about two-thirds of patients with chronic inflammatory demyelinating polyradiculoneuropathy but rapid deterioration may occur afterwards. Adverse events related to difficulty with venous access, use of citrate and haemodynamic changes are not uncommon. More research is needed to identify agents which will prolong the beneficial action of plasma exchange.