Comparing the Autoantibody Levels and Clinical Efficacy of Double Filtration Plasmapheresis, Immunoadsorption, and Intravenous Immunoglobulin for the Treatment of Late-onset Myasthenia Gravis

Assessing the comparative efficacy of plasmapheresis and Intravenous immunoglobulin in myasthenia gravis treatment: A systematic review and meta-analysis

BACKGROUND

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder characterized by muscle weakness, posing significant challenges to patients' daily lives. Intravenous immunoglobulin (IVIG) and plasmapheresis are two prominent immunomodulatory therapies used in MG management, but the choice between them remains a clinical dilemma. This systematic review and meta-analysis aim to evaluate the comparative efficacy of IVIG versus plasmapheresis in MG management.

METHODS

We adhered to PRISMA guidelines and prospectively registered the review protocol in PROSPERO. Systematic search across electronic databases identified 14 studies meeting inclusion criteria. Data from these studies were extracted, and assessed risk of bias. Primary outcomes included clinical efficacy, while secondary outcomes encompassed hospitalization, ventilation, antibody titers, and treatment-related complications. Statistical analysis was conducted using R software.

RESULTS

The pooled results indicated that patients receiving plasmapheresis had higher odds of any improvement in MG symptoms compared to IVIG. However, change in severity scores did not significantly differ between the two treatments. Hospitalization durations were similar, but IVIG-treated patients tended to have shorter stays. Antibody titers, particularly anti-MUSK antibodies, favored plasmapheresis treatment. Complication rates were comparable between two groups. However, severe complications were more common in plasmapheresis.

CONCLUSION

This comprehensive analysis suggests that plasmapheresis may offer superior short-term symptom improvement in MG compared to IVIG, while IVIG may lead to shorter hospital stays and lower complication rates. The choice between these treatments should be tailored to individual patient needs and disease characteristics. Further research is needed to explore long-term outcomes and mortality rates in MG management.

Pharmacokinetics and pharmacodynamics across infusion rates of intravenously administered nipocalimab: results of a phase 1, placebo-controlled study

Introduction

Nipocalimab is a high-affinity, fully human, aglycosylated, effectorless, immunoglobulin G (IgG) 1 monoclonal antibody that targets the neonatal Fc receptor (FcRn), decreases systemic IgG including autoantibodies, and is under development in several IgG autoantibody- and alloantibody-mediated diseases, including generalized myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, maternal-fetal medicine, and multiple other therapeutic areas. An initial phase 1 study with single and multiple ascending doses of nipocalimab infused intravenously (IV) over 2 h demonstrated dose-dependent serum pharmacokinetics and IgG reductions, with an adverse event (AE) profile comparable to placebo.

Methods

The current investigation evaluates the safety, tolerability, pharmacokinetics, and pharmacodynamics of single doses of nipocalimab across various IV infusion rates in a randomized, double-blind, placebo-controlled, sequential-dose study. Forty participants were randomized to receive nipocalimab 30 mg/kg over 60, 30, 15 or 7.5 min (0.5, 1, 2, or 4 mg/kg/min); nipocalimab 60 mg/kg over 15 min (4 mg/kg/min); or matching placebo.

Results

At doses up to 60 mg/kg and infusion rates up to 4 mg/kg/min (maximum clinically feasible rate), single doses of nipocalimab were tolerable, with 12 (40%) participants experiencing AEs across nipocalimab cohorts compared with 1 (10%) participant in the placebo cohort. AEs deemed treatment related occurred in 6 (20%) participants receiving nipocalimab and 1 (10%) participant receiving placebo. None of the AEs were severe, and no participants discontinued treatment due to AEs. Nipocalimab provided consistent, dose-dependent serum pharmacokinetics and IgG reductions, regardless of infusion rate.

Discussion

This study supports the use of shortened durations of nipocalimab infusion for future studies.

Plasma Exchange versus Intravenous Immunoglobulin in Worsening Myasthenia Gravis: A Systematic Review and Meta-Analysis with Special Attention to Faster Relapse Control

Currently used rescue interventions to prevent rapid myasthenic deterioration are plasma exchange (PLEX) and intravenous immunoglobulin (IVIG). We investigated the evidence to determine whether the two methods were interchangeable or whether one was superior to the other. This review was registered on PROSPERO (CRD42021285985). Only randomized controlled trials (RCTs) comparing the efficacy and safety of PLEX and IVIG in patients with moderate-to-severe myasthenia gravis (MG) were included. Five major databases were systematically searched (PubMed, CENTRAL, Embase, Scopus, and Web of Science). Odds ratios (OR) with 95% confidence intervals (CI) were calculated for adverse events and mean differences (MD) for changes in quantitative myasthenia gravis scores (QMG). Three RCTs met the inclusion criteria. Two investigating 114 patients in total were eligible for meta-analysis to analyze efficacy and safety. For the change in QMG score, the MD was -2.8 (95% CI: -5.614-0.113), with PLEX performing better. For adverse events, an OR of 1.04 was found (95% CI: 0.25-4.27). This study demonstrated a low risk of bias in evaluating treatment efficacy but indicated a high risk of bias in assessing procedural safety outcomes. Although the results did not show any significant difference, there was a tendency indicating faster efficacy of PLEX in the first two weeks of treatment. In such a critical clinical condition, this tendency may be clinically meaningful, but further studies should clarify this benefit.

Efficacy and Safety of Intravenous Immunoglobulin Treatment in Selected Neurological Diseases-One Centre's Experience Based on the Therapy of 141 Patients

BACKGROUND

Intravenous immunoglobulins (IVIg) are the first-choice drugs for the treatment of certain neuroimmune diseases. The aim of this study was to evaluate the efficacy and safety of IVIg in patients with selected nervous system diseases.

METHODS

The study enrolled patients who received IVIg in programmes financed by the National Health Fund in Poland. The status of patients upon inclusion and during treatment was assessed using scales dedicated to specific neurological diseases.

RESULTS

The study enrolled 141 patients aged 56.28 ± 14.72 (51.77% female): 21 patients with myasthenia gravis (MG), 65 with chronic inflammatory demyelinating polyneuropathy (CIDP), 30 with Guillain-Barré syndrome (GBS), 12 with neuromyelitis optica spectrum disorder (NMOSD) and 13 patients with autoimmune encephalitis (AE). Neurological improvement was found in 14 (66.66%) MG patients (with a reduction of at least three points on the Quantitative Myasthenia Gravis Score (QMGS) within 14 days from the completion of the cycle), and in 34 (52.3%) GBS patients (with a reduction of at least one point on the Medical Research Council Scale within 14 days from the completion of the cycle). The parameters with the strongest effect on clinical improvement in MG patients were age [OR 1.033, CI 95% [0.09-1.09], p = 0.049] and baseline QMGS [OR 0.505; CI 95% [0.24-0.87], p = 0.038]. In the majority of CIDP patients (27, 97%) and NMOSD patients (6, 50%), neurological stabilisation was observed (without clinical improvement, defined for CIDP patients as an increase of at least two points on the Lovett Scale after three courses of IVIg were administered, and for NMOSD patients as an increase of at least one point on the Medical Research Council Scale and/or a shift of at least 0.3 logMAR after three courses of treatment). Deep-vein thrombosis was only one serious adverse event in the total group of patients treated with IVIg.

CONCLUSIONS

The use of IVIg in patients with MG and GBS mostly results in neurological improvement, while in patients with NMOSD and CIDP, it mostly results in disease stabilisation. This could indicate the predominant anti-idiotypic antibody activity of IVIg in acute neuroimmune diseases or during exacerbations in chronic autoimmune diseases. The therapy of AE in comorbid neoplastic disease is burdened with an elevated risk of failure for IVIg. The results of our study confirm the improved safety of IVIg for selected neurological diseases.

The impact of thymectomy in subgroups of Myasthenia gravis patients: a single center longitudinal observation

BACKGROUND

Myasthenia gravis (MG) is a rare neuromuscular disorder. Symptoms can range from ptosis only to life threatening myasthenic crisis. Thymectomy is recommended for anti-acetylcholine receptor-antibody positive patients with early-onset MG. Here, we investigated prognostic factors shaping therapeutic outcomes of thymectomy to improve patient stratification.

METHODS

We retrospectively collected single-center data from a specialized center for MG from all consecutive adult patients that underwent thymectomy from 01/2012 to 12/2020. We selected patients with thymoma-associated and non-thymomatous MG for further investigations. We analyzed the patient collective regarding perioperative parameters in relation to the surgical approach. Furthermore, we investigated the dynamics of the anti-acetylcholine receptor-antibody titers and concurrent immunosuppressive therapies, as well as the therapeutic outcomes in dependence of clinical classifications.

RESULTS

Of 137 patients 94 were included for further analysis. We used a minimally invasive approach in 73 patients, whereas 21 patients underwent sternotomy. A total of 45 patients were classified as early-onset MG (EOMG), 28 as late-onset MG (LOMG) and 21 as thymoma-associated MG (TAMG). The groups differed in terms of age at diagnosis (EOMG: 31.1 ± 12.2 years; LOMG: 59.8 ± 13.7 years; TAMG: 58.6 ± 16.7 years; p < 0.001). Patients with EOMG and TAMG were more often female than patients in the LOMG group (EOMG: 75.6%; LOMG: 42.9%; TAMG: 61.9%; p = 0.018). There were no significant differences in outcome scores (quantitative MG; MG activities of daily living; MG Quality of Live) with a median follow-up of 46 months. However, Complete Stable Remission was achieved significantly more frequently in the EOMG group than in the other two groups (p = 0.031). At the same time, symptoms seem to improve similarly in all three groups (p = 0.25).

CONCLUSION

Our study confirms the benefit of thymectomy in the therapy of MG. Both, the concentration of acetylcholine receptor antibodies and the necessary dosage of cortisone therapy show a continuous regression after thymectomy in the overall cohort. Beyond EOMG, groups of LOMG and thymomatous MG responded to thymectomy as well, but therapy success was less pronounced and delayed compared to the EOMG subgroup. Thymectomy is a mainstay of MG therapy to be considered in all subgroups of MG patients investigated.

Real-world application of plasmapheresis for neurological disease: Results from the Japan-Plasmapheresis Outcome and Practice Patterns Study

INTRODUCTION

Plasmapheresis is a well-recognized treatment for autoimmune neurological diseases in Japan. However, the practice varies depending on the facility, and the actual treatment conditions are unclear.

METHODS

To clarify real-world conditions, a prospective observational study was conducted on patients with neurological diseases who were scheduled to receive plasmapheresis. A dataset was analyzed that included 887 treatments from 210 patients with myasthenia gravis (MG), multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and other diseases for 82, 30, 24, and 74 patients, respectively.

RESULTS

The types of plasmapheresis performed included immunoadsorption plasmapheresis, plasma exchange, and double filtration plasmapheresis with 620, 213, and 54 treatments, respectively. Approximately, 60% of the treatments were performed using peripheral blood access alone. Non-serious adverse events were observed in 10 patients.

CONCLUSIONS

A statistically significant improvement was observed after plasmapheresis in patients with MG, MS, and NMOSD. These were evaluated using the modified Rankin Scale.

Comparison of IVIg and TPE efficacy in the treatment of neurological disorders: a systematic literature review

Background:

Intravenous immunoglobulin (IVIg) and therapeutic plasma exchange (TPE) are among the main immunotherapies for neurological disorders. Their benefit is greatest in immune-mediated conditions, but their distinct efficacy cannot be simply explained.

Objectives:

This review aimed to systematically identify studies comparing the efficacy of TPE and IVIg treatments for selected autoimmune neurological disorders and identify optimal therapies for each condition.

Data Sources and Methods:

PubMed, MEDLINE and Embase databases were searched for original publications from 1990 to 2021. Additional publications were identified via expert recommendations. Conference abstracts older than 2017, review articles and articles without information on TPE and IVIg comparison in title and abstract were excluded. Risks of bias were descriptively addressed, without a meta-analysis.

Results:

Forty-four studies were included on Guillain–Barré syndrome (20 studies – 12 adult, 5 paediatric, 3 all ages), myasthenia gravis (11 studies –8 adult, 3 paediatric), chronic immune–mediated polyradiculoneuropathy (3 studies –1 adult, 2 paediatric), encephalitis (1 study in adults), neuromyelitis optica spectrum disorders (5 studies –2 adult, 3 all ages) and other conditions (4 studies – all ages). TPE and IVIg were mostly similarly efficacious, measured by clinical outcomes and disease severity scores. Some studies recommended IVIg as easy to administer. TPE procedures, however, have been simplified and the safety has been improved. TPE is currently recommended for management of neuromyelitis optica spectrum disorder relapses and some myasthenia gravis subtypes, in which rapid removal of autoantibodies is crucial.

Conclusion:

Despite some limitations (e.g. the low evidence levels), this review provides an extensive 30-year-long overview of treatments for various conditions. Both IVIg and TPE are usually comparably efficacious options for autoimmune neurological disorders, with few exceptions. Treatment choices should be patient-tailored and based on available clinical resources. Better designed studies are needed to provide higher-level quality of evidence regarding clinical efficacy of TPE and IVIg treatments.

Role of autoantibody levels as biomarkers in the management of patients with myasthenia gravis: A systematic review and expert appraisal

BACKGROUND AND PURPOSE

Although myasthenia gravis (MG) is recognized as an immunoglobulin G autoantibody-mediated disease, the relationship between autoantibody levels and disease activity in MG is unclear. We sought to evaluate this landscape through systematically assessing the evidence, testing the impact of predefined variables on any relationship, and augmenting with expert opinion.

METHODS

In October 2020, a forum of leading clinicians and researchers in neurology from across Europe (Expert Forum for Rare Autoantibodies in Neurology in Myasthenia Gravis) participated in a series of virtual meetings that took place alongside the conduct of a systematic literature review (SLR).

RESULTS

Forty-two studies were identified meeting inclusion criteria. Of these, 10 reported some correlation between a patient's autoantibody level and disease severity. Generally, decreased autoantibody levels (acetylcholine receptor, muscle-specific kinase, and titin) were positively and significantly correlated with improvements in disease severity (Quantitative Myasthenia Gravis score, Myasthenia Gravis Composite score, Myasthenia Gravis Activities of Daily Living score, Myasthenia Gravis Foundation of America classification). Given the limited evidence, testing the impact of predefined variables was not feasible.

CONCLUSIONS

This first SLR to assess whether a correlation exists between autoantibody levels and disease activity in patients with MG has indicated a potential positive correlation, which could have clinical implications in guiding treatment decisions. However, in light of the limited and variable evidence, we cannot currently recommend routine clinical use of autoantibody level testing in this context. For now, patient's characteristics, clinical disease course, and laboratory data (e.g., autoantibody status, thymus histology) should inform management, alongside patient-reported outcomes. We highlight the need for future studies to reach more definitive conclusions on this relationship.

Changes in Water Properties in Human Tissue after Double Filtration Plasmapheresis-A Case Study

Double-filtration plasmapheresis (DFPP) is a blood cleaning technique that enables the removal of unwanted substances from the blood. In our case study, we performed near-infrared (NIR) spectroscopy measurements on the human hand tissue before and after a specific DFPP treatment (INUSpheresis with a TKM58 filter), along with NIR measurements of the substances extracted via DFPP (eluate). The spectral data were analyzed using the aquaphotomics approach. The analysis showed that the water properties in the tissue change after DFPP treatment, i.e., an increase in small water clusters, free water molecules and a decrease in hydroxylated water as well as superoxide in hydration shells was noted. The opposite effect was observed in the eluates of both DFPP treatments. Our study is the first that documents changes in water spectral properties after DFPP treatments in human tissue. The changes in tissue water demonstrated by our case study suggest that the positive physiological effects of DFPP in general, and of INUSpheresis with the TKM58 filter in particular, may be associated with improvements in water quality in blood and tissues.

Lymphoplasma Exchange Improves Myasthenia Gravis Exacerbations: A Retrospective Study in a Chinese Center

Background

Lymphoplasma exchange (LPE), a technique combining plasma exchange with leukapheresis, is emerging as promising treatment for autoimmune diseases. Data on the efficacy and safety of LPE in myasthenia gravis (MG) therapy are scarce. In this study, we aimed to comprehensively review the clinical efficacy, safety, and immunological characteristics of LPE therapy in MG patients.

Study Design and Methods

A Chinese cohort of 276 generalized MG patients in state of exacerbation, including impeding crisis, myasthenia crisis, and preparation for thoracic exsection between January 2014 and December 2020, were evaluated in this study.

Results

A total of 276 patients with a median age of 45.5 ± 16.7 years underwent a total of 635 LPE sessions. Clinical scales of Quantitative Myasthenia Gravis (QMG) scores, Myasthenia Gravis Specific Manual Muscle Testing (MMT) scores, activities of daily living (ADL) scores, and quality of life (QOL) scores were improved during 4 weeks’ follow-up. Adverse effects occurred in 20 out of 276 patients, with 14 patients having one adverse event each. Independent predictive factors for good response to LPE therapy were symptom onset before LPE therapy ≤3 days and age on LPE therapy <50 years of age. LPE decreased the serum levels of antibodies, immunoglobulins, and complements 4 weeks after the first replacement, with decreased levels of interleukin (IL)-17A and interferon (IFN)-γ and increased level of IL-10.

Conclusion

LPE is an effective treatment for MG patients in state of exacerbation and preparation for thymectomy. Early use of LPE on early-onset MG may have good therapeutic effects. The potential mechanism for LPE is the polarization of cytokines from IL-17A, IFN-γ, into IL-10.

Therapeutic Plasma Exchange: For Cancer Patients

Therapeutic plasma exchange is used as a trial method for the treatment of cancer patients. Therapeutic plasma exchange uses in vitro technology to remove pathogenic factors in the plasma, returning the replacement and remaining components to the patient to facilitate cure. In the effort to explore new methods of cancer treatment, the introduction of therapeutic plasma exchange brings new hope for cancer treatment; however, the current evidence supporting therapeutic plasma exchange is controversial, and most of the evidence comes from observational studies, lacking large prospective randomized trials. Therefore, this review attempts to focus on the main indications of therapeutic plasma exchange for the treatment of tumors and their complications, including hematological tumors (multiple myeloma cast nephropathy and hyperviscosity syndrome), nervous system tumors (myasthenia gravis associated with thymoma, paraneoplastic neurological syndrome, Lambert–Eaton myasthenia syndrome, and anti-N-methyl-D-aspartate receptor encephalitis), overdose of chemotherapy drugs. In addition, the issues of side-effects and safety in the use of therapeutic plasma exchange are also discussed. However, well-designed prospective trials are needed to better define the role of therapeutic plasma exchange in cancer.

Efficacy of intravenous immunoglobulin in autoimmune neurological diseases. Literature systematic review and meta-analysis

BACKGROUND

Corticosteroids are the first-line treatment for several common autoimmune neurological diseases. Other therapeutic approaches, including intravenous immunoglobulin (IVIg) and plasmapheresis, have shown mixed results in patient improvement.

OBJECTIVE

To compare the efficacy of IVIg administration with that of corticosteroids, plasmapheresis, and placebo in autoimmune neurological diseases like Guillain-Barré syndrome, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, optic neuritis, and multiple sclerosis.

METHODS

A systematic review was performed on the databases PubMed, MEDLINE, Embase, and Cochrane. Controlled, randomized studies comparing the efficacy of IVIg with placebo, plasmapheresis, and/or glucocorticoid administration were selected. Only studies reporting the number of patients who improved after treatment were included, irrespective of language or publication year. In total, 23 reports were included in the meta-analysis study.

RESULTS

Our meta-analysis showed a beneficial effect of IVIg administration on patient improvement over placebo (OR = 2.79, CI [95%] = 1.40-5.55, P = 0.01). Meanwhile, IVIg administration showed virtually identical effects to plasmapheresis (OR = 0.83, CI [95%] = 0.45-1.55, P < 0.01). Finally, no significant differences were found in the efficacy of IVIg and glucocorticoid administration (OR = 0.98, Cl [95%] = 0.58-1.68, P = 0.13).

CONCLUSION

IVIg can be regarded as a viable therapeutic approach, either as a first- or second-line therapy, and as an adjuvant therapy for autoimmune neurological diseases.

Immunoadsorption apheresis versus intravenous immunoglobulin therapy for exacerbation of myasthenia gravis

Immunoadsorption apheresis (IA) or intravenous immunoglobulin (IVIg) is used to treat exacerbation of myasthenia gravis (MG). This study aimed to compare the efficacy and safety between IA and IVIg for MG patients with anti-acetylcholine receptor (AChR) antibodies. We retrospectively studied 19 AChR antibody-positive generalized MG patients who underwent IA (n = 9) or IVIg treatment (n = 10). We reviewed the MG activities of daily living profile (MG-ADL) scores at baseline, 1 and 3 months after the treatment. Adverse events during the treatment period were also reviewed. The MG-ADL scores showed significantly greater improvement from the baseline in the IA group than in the IVIg group (1 month: -7 vs -3, P = .035; 3 months -9 vs -2.5, P = .016). An adverse event that led to the discontinuation of the treatment was observed in only one patient in the IVIg group (anaphylactic reaction). Our data suggest that the IA treatment is safe and more efficacious than the IVIg treatment for aggravation of anti-AChR-positive MG. Larger prospective studies are required to confirm the finding.

IgG regulation through FcRn blocking: A novel mechanism for the treatment of myasthenia gravis

The neonatal Fc receptor (FcRn) is an MHC class I-like molecule that is widely distributed in mammalian organs, tissues, and cells. FcRn is critical to maintaining immunoglobulin G (IgG) and albumin levels through rescuing these molecules from lysosomal degradation. IgG autoantibodies are associated with many autoimmune diseases, including myasthenia gravis (MG), a rare neuromuscular autoimmune disease that causes debilitating and, in its generalized form (gMG), potentially life-threatening muscle weakness. IgG autoantibodies are directly pathogenic in MG and target neuromuscular junction proteins, causing neuromuscular transmission failure. Treatment approaches that reduce autoantibody levels, such as therapeutic plasma exchange and intravenous immunoglobulin, have been shown to be effective for gMG patients but are not indicated as ongoing maintenance therapies and can be associated with burdensome side effects. Agents that block FcRn-mediated recycling of IgG represent a rational and promising approach for the treatment of gMG. Blocking FcRn allows targeted reduction of all IgG subtypes without decreasing concentrations of other Ig isotypes; therefore, FcRn blocking could be a safe and effective treatment strategy for a broad population of gMG patients. Several FcRn-blocking antibodies and one antibody Fc fragment have been developed and are currently in various stages of clinical development. This article describes the mechanism of FcRn blockade as a novel approach for IgG-mediated disease therapy and reviews promising clinical data using such FcRn blockers for the treatment of gMG.

Safety, efficacy, and tolerability of efgartigimod in patients with generalised myasthenia gravis (ADAPT): a multicentre, randomised, placebo-controlled, phase 3 trial

BACKGROUND

There is an unmet need for treatment options for generalised myasthenia gravis that are effective, targeted, well tolerated, and can be used in a broad population of patients. We aimed to assess the safety and efficacy of efgartigimod (ARGX-113), a human IgG1 antibody Fc fragment engineered to reduce pathogenic IgG autoantibody levels, in patients with generalised myasthenia gravis.

METHODS

ADAPT was a randomised, double-blind, placebo-controlled, phase 3 trial done at 56 neuromuscular academic and community centres in 15 countries in North America, Europe, and Japan. Patients aged at least 18 years with generalised myasthenia gravis were eligible to participate in the study, regardless of anti-acetylcholine receptor antibody status, if they had a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of at least 5 (>50% non-ocular), and were on a stable dose of at least one treatment for generalised myasthenia gravis. Patients were randomly assigned by interactive response technology (1:1) to efgartigimod (10 mg/kg) or matching placebo, administered as four infusions per cycle (one infusion per week), repeated as needed depending on clinical response no sooner than 8 weeks after initiation of the previous cycle. Patients, investigators, and clinical site staff were all masked to treatment allocation. The primary endpoint was proportion of acetylcholine receptor antibody-positive patients who were MG-ADL responders (≥2-point MG-ADL improvement sustained for ≥4 weeks) in the first treatment cycle. The primary analysis was done in the modified intention-to-treat population of all acetylcholine receptor antibody-positive patients who had a valid baseline MG-ADL assessment and at least one post-baseline MG-ADL assessment. The safety analysis included all randomly assigned patients who received at least one dose or part dose of efgartigimod or placebo. This trial is registered at ClinicalTrials.gov (NCT03669588); an open-label extension is ongoing (ADAPT+, NCT03770403).

FINDINGS

Between Sept 5, 2018, and Nov 26, 2019, 167 patients (84 in the efgartigimod group and 83 in the placebo group) were enrolled, randomly assigned, and treated. 129 (77%) were acetylcholine receptor antibody-positive. Of these patients, more of those in the efgartigimod group were MG-ADL responders (44 [68%] of 65) in cycle 1 than in the placebo group (19 [30%] of 64), with an odds ratio of 4·95 (95% CI 2·21-11·53, p<0·0001). 65 (77%) of 84 patients in the efgartigimod group and 70 (84%) of 83 in the placebo group had treatment-emergent adverse events, with the most frequent being headache (efgartigimod 24 [29%] vs placebo 23 [28%]) and nasopharyngitis (efgartigimod ten [12%] vs placebo 15 [18%]). Four (5%) efgartigimod-treated patients and seven (8%) patients in the placebo group had a serious adverse event. Three patients in each treatment group (4%) discontinued treatment during the study. There were no deaths.

INTERPRETATION

Efgartigimod was well tolerated and efficacious in patients with generalised myasthenia gravis. The individualised dosing based on clinical response was a unique feature of ADAPT, and translation to clinical practice with longer term safety and efficacy data will be further informed by the ongoing open-label extension.

FUNDING

argenx.

Protein A immunoadsorption for the treatment of refractory anti-N-methyl-d-aspartate receptor encephalitis: A single-center prospective study

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of protein A immunoadsorption (IA) for anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis resistant to intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIG).

METHODS

We prospectively evaluated patients with refractory anti-NMDAR encephalitis, treated with protein A IA. Demographic data, clinical characteristics, modified Rankin Score (mRS), and anti-NMDAR antibodies were documented before and after IA and at follow-up. Clinical improvement was defined as a decrease of mRS ≥1. Adverse events were recorded throughout the study.

RESULTS

Ten patients with mRS ≥3 were enrolled and treated with protein A IA; treatment was performed for an average of 5.2 times per patient. Among the nine patients with positive serum anti-NMDAR, the titer decreased in seven patients, of which two became negative. The cerebrospinal fluid (CSF) anti-NMDAR titer decreased in all patients, and one became negative. Anti-NMDAR levels were tested in two patients at follow-up and found to have declined continuously. All patients exhibited clinical improvement with a mRS decline ≥1 after IA treatment (median mRS: 5.0 [range, 3.0-5.0] vs. 4.0 [range, 2.0-4.0], p = 0.014), and the median mRS decreased to 1.0 (range, 0-3.0) at follow-up. After IA, all patients exhibited accelerated recovery. No adverse events were observed during IA treatment.

CONCLUSION

Protein A IA may be effective for treating IVMP/IVIG-resistant anti-NMDAR encephalitis and well tolerated. It is necessary to initiate larger-scale prospective controlled studies to validate the efficacy and safety of protein A IA in anti-NMDAR encephalitis.

Efficacy and safety of double-filtration plasmapheresis treatment of myasthenia gravis: A systematic review and meta-analysis

OBJECTIVES

To evaluate the efficacy of double-filtration plasmapheresis (DFPP) treatment of myasthenia gravis (MG) through a systematic review and meta-analysis.

METHODS

PubMed, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals Database (VIP), and Wanfang databases were searched for randomized controlled trials (RCTs) and clinical controlled trials (CCTs) on DFPP for MG from database establishment to June 2019. Two researchers independently screened the articles, extracted the data, and cross checked the results. RevMan 5.3 was used for statistical analyses.

RESULTS

Seven RCTs and 2 CCTs were found comprising 329 patients. The results showed that clinical MG remission rate after DFPP treatment was significantly higher (OR = 4.33; 95% confidence interval [CI], 1.97-9.53; P < .001) and the serum levels of antititin antibody was significantly decreased (standardized mean difference [SMD] = 9.30; 95% CI, 7.51-11.08; P < .001). In addition, the quantitative MG (QMG) score, hospital stay and time to remission of MG symptoms, and acetylcholine receptor antibody (AchRAb) decreased in the DFPP treatment group; however, these outcomes had high heterogeneity among the studies. Only one study has reported on the adverse effects, including hypotension and hematoma.

CONCLUSION

This meta-analysis suggests that DFPP can be recommended for the short-term mitigation of MG. Because our review was limited by the quantity and quality of the included studies, the above conclusions should be verified by additional high-quality studies.

Treatment of refractory myasthenia gravis by double-filtration plasmapheresis and rituximab: A case series of nine patients and literature review

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease mediated by circulating autoantibodies (anti-AchR, anti-MuSK, etc.). More than 20% of myasthenic patients are refractory to conventional treatments (plasma exchange, IVIg, steroids, azathioprine, mycophenolate mofetil). Rituximab (B-lymphocyte-depleting anti-CD20) and apheresis (double-filtration plasmapheresis [DFPP] and immunoadsorption [IA]) are interesting therapeutic alternatives.

METHODS

This monocentric pilot study included nine refractory myasthenic patients (March 2018 to May 2020) treated by DFPP and/or IA associated with rituximab (375 mg/m² ). Clinical responses were assessed using the Myasthenia Gravis Foundation of America (MGFA) score.

RESULTS

Average age of patients was 53 ± 17 years. Gender ratio (M/F) was 3:6. The combination of apheresis and rituximab reduced median MGFA score from IV to II after 12 months of follow-up. Clinical improvement assessed by MGFA score was sustained in the long-term for all patients, during an average follow-up of 14 ± 9 months, allowing them to be self-sufficient and out sick-leave. The median number of apheresis sessions was 7 (5-30). The dose of prednisolone was reduced in two patients from 40 mg/d and 30 mg/d to 7.5 mg/d and 10 mg/d, respectively. It was stopped in a patient who was taking 30 mg/d. No infectious, bleeding, or thrombosis complications were noted.

CONCLUSION

The combination of rituximab and DFPP was effective to treat refractory MG.

Blocking FcRn in humans reduces circulating IgG levels and inhibits IgG immune complex-mediated immune responses

The neonatal crystallizable fragment receptor (FcRn) functions as an intracellular protection receptor for immunoglobulin G (IgG). Recently, several clinical studies have reported the lowering of circulating monomeric IgG levels through FcRn blockade for the potential treatment of autoimmune diseases. Many autoimmune diseases, however, are derived from the effects of IgG immune complexes (ICs). We generated, characterized, and assessed the effects of SYNT001, a FcRn-blocking monoclonal antibody, in mice, nonhuman primates (NHPs), and humans. SYNT001 decreased all IgG subtypes and IgG ICs in the circulation of humans, as we show in a first-in-human phase 1, single ascending dose study. In addition, IgG IC induction of inflammatory pathways was dependent on FcRn and inhibited by SYNT001. These studies expand the role of FcRn in humans by showing that it controls not only IgG protection from catabolism but also inflammatory pathways associated with IgG ICs involved in a variety of autoimmune diseases.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Clinical outcome measures following plasma exchange for MG exacerbation

Our objective is to report longitudinal results of the MG‐ADL, MG‐Composite, MG‐MMT, and MG‐QoL15 in an open‐label trial of therapeutic plasma exchange in myasthenia gravis. Ten MG patients experiencing exacerbation had assessments prior to, immediately following, and at selected time points post‐TPE. Changes from baseline to 2 weeks post‐TPE were: MG‐ADL median −5.0, P < 0.0033, MG‐QoL15 median −13.0, P < 0.001, MG‐MMT median −10.0, P < 0.0001, and MG‐Composite median −10.0, P < 0.005. TPE produced a rapid, clinically significant change in all instruments, indicating these outcome measures are robust endpoints for clinical trials of rapidly efficacious MG therapies.

[Myasthenia gravis]

Myasthenia gravis (MG) is an autoimmune disorder caused by antibodies against acetylcholine receptors (AChR) or other structural proteins of the neuromuscular junction. This diminishes cholinergic transmission, thus leading to exercise-induced fatigue and sometimes manifest muscle weakness, including the bulbar and ocular musculature. Whereas ocular MG is as a rule initially symptomatically treated with acetylcholine esterase inhibitors, generalized MG requires long-term immunosuppression. The thymus plays a particular role in the pathophysiology of AChR antibody-positive MG, which can also manifest as a paraneoplastic disorder in the context of a thymoma. This article reviews the basic and advanced treatment options of the different disease subtypes including plasma exchange and immunoglobulins for treatment in a myasthenic crisis. Recently, clinical approval of eculizumab, a complement inhibitor, enriched the pharmacological armamentarium for AChR antibody-positive MG patients not appropriately responding to immunosuppression alone.

Randomized phase 2 study of FcRn antagonist efgartigimod in generalized myasthenia gravis

OBJECTIVE

To investigate safety and explore efficacy of efgartigimod (ARGX-113), an anti-neonatal Fc receptor immunoglobulin G1 Fc fragment, in patients with generalized myasthenia gravis (gMG) with a history of anti-acetylcholine receptor (AChR) autoantibodies, who were on stable standard-of-care myasthenia gravis (MG) treatment.

METHODS

A phase 2, exploratory, randomized, double-blind, placebo-controlled, 15-center study is described. Eligible patients were randomly assigned (1:1) to receive 4 doses over a 3-week period of either 10 mg/kg IV efgartigimod or matched placebo combined with their standard-of-care therapy. Primary endpoints were safety and tolerability. Secondary endpoints included efficacy (change from baseline to week 11 of Myasthenia Gravis Activities of Daily Living, Quantitative Myasthenia Gravis, and Myasthenia Gravis Composite disease severity scores, and of the revised 15-item Myasthenia Gravis Quality of Life scale), pharmacokinetics, pharmacodynamics, and immunogenicity.

RESULTS

Of the 35 screened patients, 24 were enrolled and randomized: 12 received efgartigimod and 12 placebo. Efgartigimod was well-tolerated in all patients, with no serious or severe adverse events reported, no relevant changes in vital signs or ECG findings observed, and no difference in adverse events between efgartigimod and placebo treatment. All patients treated with efgartigimod showed a rapid decrease in total immunoglobulin G (IgG) and anti-AChR autoantibody levels, and assessment using all 4 efficacy scales consistently demonstrated that 75% showed a rapid and long-lasting disease improvement.

CONCLUSIONS

Efgartigimod was safe and well-tolerated. The correlation between reduction of levels of pathogenic IgG autoantibodies and disease improvement suggests that reducing pathogenic autoantibodies with efgartigimod may offer an innovative approach to treat MG.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that efgartigimod is safe and well-tolerated in patients with gMG.

M281, an Anti-FcRn Antibody: Pharmacodynamics, Pharmacokinetics, and Safety Across the Full Range of IgG Reduction in a First-in-Human Study

M281 is a fully human, anti-neonatal Fc receptor (FcRn) antibody that inhibits FcRn-mediated immunoglobulin G (IgG) recycling to decrease pathogenic IgG while preserving IgG production. A randomized, double-blind, placebo-controlled, first-in-human study with 50 normal healthy volunteers was designed to probe safety and the physiological maximum for reduction of IgG. Intravenous infusion of single ascending doses up to 60 mg/kg induced dose-dependent serum IgG reductions, which were similar across all IgG subclasses. Multiple weekly doses of 15 or 30 mg/kg achieved mean IgG reductions of ≈85% from baseline and maintained IgG reductions ≥75% from baseline for up to 24 days. M281 was well tolerated, with no serious or severe adverse events (AEs), few moderate AEs, and a low incidence of infection-related AEs similar to placebo treatment. The tolerability and consistency of M281 pharmacokinetics and pharmacodynamics support further evaluation of M281 in diseases mediated by pathogenic IgG.

Neonatal Fc receptor antagonist efgartigimod safely and sustainably reduces IgGs in humans

BACKGROUND

Intravenous Ig (IVIg), plasma exchange, and immunoadsorption are frequently used in the management of severe autoimmune diseases mediated by pathogenic IgG autoantibodies. These approaches modulating IgG levels can, however, be associated with some severe adverse reactions and a substantial burden to patients. Targeting the neonatal Fc receptor (FcRn) presents an innovative and potentially more effective, safer, and more convenient alternative for clearing pathogenic IgGs.

METHODS

A randomized, double-blind, placebo-controlled first-in-human study was conducted in 62 healthy volunteers to explore single and multiple ascending intravenous doses of the FcRn antagonist efgartigimod. The study objectives were to assess safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity. The findings of this study were compared with the pharmacodynamics profile elicited by efgartigimod in cynomolgus monkeys.

RESULTS

Efgartigimod treatment resulted in a rapid and specific clearance of serum IgG levels in both cynomolgus monkeys and healthy volunteers. In humans, single administration of efgartigimod reduced IgG levels up to 50%, while multiple dosing further lowered IgGs on average by 75% of baseline levels. Approximately 8 weeks following the last administration, IgG levels returned to baseline. Efgartigimod did not alter the homeostasis of albumin or Igs other than IgG, and no serious adverse events related to efgartigimod infusion were observed.

CONCLUSION

Antagonizing FcRn using efgartigimod is safe and results in a specific, profound, and sustained reduction of serum IgG levels. These results warrant further evaluation of this therapeutic approach in IgG-driven autoimmune diseases.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03457649.

FUNDING

argenx BVBA.

CTLA-4 methylation regulates the pathogenesis of myasthenia gravis and the expression of related cytokines

BACKGROUND

Myasthenia gravis (MG) is a progressive autoimmune disease that occurs as a result of the failure of neuromuscular transmission and is characterized by muscle weakness. There has been evidence on the correlations between the genetic predisposition of cytotoxic T lymphocyte and the antigen-4 (CTLA-4) and MG. Thus, the present study was conducted to study is designed to examine the effects of CTLA-4 methylation on the pathogenesis of MG and the expressions of related cytokines.

METHODS

The CTLA-4 methylation levels in peripheral blood were quantified in 103 samples collected from MG patients and 86 samples from healthy individiuals. The expression of serum-related cytokines as well as the Treg cell ratio were examined so as to define the contributory role of CTLA-4 methylation in MG and to identify the interaction between CTLA-4 methylation and related factors, the expressions of DNA methyltransferase (DNMT)l, DNMT3A and DNMT3B, CTLA-4, AchR-Ab, Titin-Ab, RyR-Ab, IL-2, IL-10, IFN-γ, and TGF-β, activity of P- acetylcholinesterase (AchE) and E-AchE.

RESULTS

The results indicated that the incidence of CTLA-4 methylation was significantly higher in the control group when compared with the MG group, and CTLA-4 methylation was also found to be associated with the thymus status of MG patients. It was also observed from the experiment data that the expressions of DNMTl, DNMT3A, and DNMT3B, along with the expressions of AchR-Ab, Titin-Ab, RyR-Ab, IL-2, IL-10, IFN-γ and TGF-β, and the activity of P-AchE and E-AchE were all higher in the MG group than in the control group, with a reduction of CTLA-4 expression. Another key finding from this study revealed that methylation interference can lead to the suppression in the expression of AchR-Ab, the activity of E-AchE, the expression of IL-2, IL-10, IFN-γ, and TGF-β and the Treg cell ratio in lymphocytes.

CONCLUSION

In conclusion, the results obtained from the present study highly indicated that CTLA-4 methylation might play a role in facilitating the occurrence of MG and increasing the expressions of related cytokines through the upregulation of AchR-Ab and E-Ach.

Safety Aspects of Immunoadsorption in IgG Removal Using a Single-Use, Multiple-pass Protein A Immunoadsorber (LIGASORB): Clinical Investigation in Healthy Volunteers

Therapeutic apheresis and immunoadsorption are used to deplete efficiently pathogenic autoantibodies in crises in several acute autoimmune driven diseases. This prospective, non-comparative cohort study was conducted at a single study center under standardized conditions in 10 healthy volunteers. Efficient immunoglobulin G (IgG) removal (-86% versus baseline) was achieved after 3 apheresis treatments on 3 consecutive days. The treatments were well tolerated. Safety laboratory parameters did not show unexpected or pathological changes. The effects were transient, with most parameters exhibiting complete recovery between treatments. Minimal complement activation and moderate transient fibrinogen depletion were observed. Immunoadsorption with LIGASORB® provides a safe and effective treatment alternative to TPE in acute episodes of peripheral neurological diseases mediated by pathogenic IgG autoantibodies.

Human Immunoglobulin Versus Plasmapheresis in Guillain-Barre Syndrome and Myasthenia Gravis: A Meta-Analysis

OBJECTIVES

To evaluate the efficacy and safety over a short time period of human intravenous immunoglobulin versus plasma exchange (PE) in the management of some autoimmune neurologic diseases. In addition, length of hospital stay and duration of ventilator support were compared.

METHODS

Randomized controlled trials and analytical observational studies of more than 10 cases were reviewed. Cochrane Neuromuscular Disease Group trials, MEDLINE, EMBASE, HINARI, and Ovid, were searched as data source. Reference lists were examined for further relevant articles. A random-effect model was used to derive a pooled risk ratio.

RESULTS

A total of 552 articles were found and 24 met the criteria for a studied population of 4657 cases: 14 articles were about Guillain-Barré syndrome and 10 of myasthenia gravis. No evidence was found to suggest that PE or intravenous immunoglobulin differed in terms of efficacy or safety to treat any of the 2 diseases. Hospital stay length and ventilatory support time are different in each illness; however, we found no statistical difference in either of the 2 treatments.

CONCLUSIONS

There is no evidence for superiority in the efficacy or safety of immunoglobulin or plasmapheresis in the management of Guillain-Barré syndrome and myasthenia gravis. However, caution should be exercised in the interpretation of these results given the limitations in the quality of the evidence and the heterogeneity of the studies.

Immunoadsorption versus plasma exchange versus combination for treatment of myasthenic deterioration

OBJECTIVES

The goal of this study was to analyze safety and assess the efficacy of standard plasma exchange (PE) compared with immunoadsorption (IA) alone, or an alternating combination of both in deteriorating myasthenia gravis (MG).

METHODS

A total of 72 patients with MG who had received PE procedures for treatment of severe deterioration were retrospectively analyzed. They received either five cycles of PE (1-1.5 plasma volumes), or five cycles of IA in line with plasma separation, or a sequential alternating procedure of one cycle of PE followed by two cycles of IA, which was repeated once or more if needed.

RESULTS

A total of 19 patients received PE, 24 patients IA, and 29 the alternating combination therapy. All groups were equally distributed by sex and mean MG score before treatment. The number of treatment cycles and days on therapy did not differ between the groups. Mean MG scores at discharge were 3.0 (PE), 1.8 (IA) and 1.6 (combination) (p = 0.028 for combination versus PE). Inpatient time was 30.7 days (PE), 22.3 days (IA) and 20.0 days in combination therapy (p < 0.05 for combination versus PE). Side effects such as allergic reactions or hypocoagulability were significantly more frequent in the PE group (37% in PE versus 4% in IA and 3.6% in the alternating combination, p < 0.05).

CONCLUSION

Semiselective IA in combination with PE, and to a lesser extent IA alone, was associated with a shorter hospital stay and more pronounced reduction of the MG score than PE.

Immunoadsorption in patients with autoimmune ion channel disorders of the peripheral nervous system

Autoimmune ion channel disorders of the peripheral nervous system include myasthenia gravis, the Lambert-Eaton myasthenic syndrome, acquired neuromyotonia and autoimmune autonomic ganglionopathies. These disorders are characterized by the common feature of being mediated by IgG autoantibodies against identified target antigens, i.e. the acetylcholine receptor, the voltage-gated calcium and potassium channels, and the neuronal acetylcholine receptor. Moreover, experimental animal models have been identified for these diseases that respond to immunotherapy and are improved by plasmapheresis. On this basis, autoimmune ion channel disorders represent the ideal candidate for therapeutic apheresis. Immunoadsorption can be the treatment of choice when intensive apheretic protocols or long-term treatments must be performed, in patients needing frequent apheresis to keep a stable clinical condition, in case of unresponsiveness to corticosteroids and immunosuppressive treatments, or failure with TPE or intravenous immunoglobulins, and in patients with severe contraindications to long-term corticosteroids.

Intravenous immunoglobulin for myasthenia gravis

BACKGROUND

Myasthenia gravis is an autoimmune disease in which autoantibodies interfere with neuromuscular transmission. As with other autoimmune diseases, people with myasthenia gravis would be expected to benefit from intravenous immunoglobulin (IVIg). This is an update of a review first published in 2003 and last updated in 2007.

OBJECTIVES

To examine the efficacy of IVIg for treating exacerbations of myasthenia gravis or for chronic myasthenia gravis.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (11 October 2011), CENTRAL (2011, Issue 3), MEDLINE (January 1966 to September 2011) and EMBASE (January 1980 to September 2011) using 'myasthenia gravis' and 'intravenous immunoglobulin' as the search terms.

SELECTION CRITERIA

All randomised controlled trials (RCTs) or quasi-RCTs in which IVIg was compared with no treatment, placebo or plasma exchange, in people with myasthenia gravis.

DATA COLLECTION AND ANALYSIS

One review author extracted the data and two others checked these data. For methodological reasons, no formal meta-analysis was performed.

MAIN RESULTS

We identified seven RCTs. These trials differ in inclusion criteria, comparison with alternative treatment and outcomes. In a trial comparing IVIg with placebo, including 51 participants with myasthenia gravis worsening, the mean difference (MD) in quantitative myasthenia gravis score (QMGS) (MD 95% CI) after 14 days was: -1.60 (95% CI - 3.23 to 0.03) this result being borderline statistically significant in favour of IVIg. In an unblinded study of 87 participants with exacerbation comparing IVIg and plasma exchange there was no difference in myasthenic muscle score (MMS) after 15 days (MD -1.00; 95% CI -7.72 to 5.72). In a study of 84 participants with worsening myasthenia gravis there was no difference in change in QMGS 14 days after IVIg or plasma exchange (MD -1.50; 95% CI -3.43 to 0.43). In a study of 12 participants with moderate or severe myasthenia gravis, which was at high risk of bias from skewed allocation, the mean fall in QMGS both for IVIg and plasma exchange after four weeks was significant (P < 0.05). A study with 15 participants with mild or moderate myasthenia gravis found no difference in change in QMGS 42 days after IVIg or placebo (MD 1.60; 95% CI -1.92 to 5.12). A study included 33 participants with moderate exacerbations of myasthenia gravis and showed no difference in change in QMGS 14 days after IVIg or methylprednisolone (MD -0.42; 95% CI -1.20 to 0.36). All these three smaller studies were underpowered. The last trial, including 168 people with exacerbations, showed no evidence of superiority of IVIg 2 g/kg over IVIg 1 g/kg on the change of MMS after 15 days (MD 3.84; 95% CI -0.98 to 8.66). Adverse events due to IVIg were moderate (fever, nausea, headache), self-limiting and subjectively less severe than with plasma exchange (although, given the available data, no statistical comparison was possible). Other than where specific limitations are mentioned the trials were generally at low risk of bias.

AUTHORS' CONCLUSIONS

In exacerbation of myasthenia gravis, one RCT of IVIg versus placebo showed some evidence of the efficacy of IVIg and two did not show a significant difference between IVIg and plasma exchange. Another showed no significant difference in efficacy between 1 g/kg and 2 g/kg of IVIg. A further, but underpowered, trial showed no significant difference between IVIg and oral methylprednisolone. In chronic myasthenia gravis, there is insufficient evidence from RCTs to determine whether IVIg is efficacious.

Treatment of myasthenia gravis based on its immunopathogenesis

The prognosis of myasthenia gravis (MG) has improved dramatically due to advances in critical-care medicine and symptomatic treatments. Its immunopathogenesis is fundamentally a T-cell-dependent autoimmune process resulting from loss of tolerance toward self-antigens in the thymus. Thymectomy is based on this immunological background. For MG patients who are inadequately controlled with sufficient symptomatic treatment or fail to achieve remission after thymectomy, remission is usually achieved through the addition of other immunotherapies. These immunotherapies can be classified into two groups: rapid induction and long-term maintenance. Rapid induction therapy includes intravenous immunoglobulin (IVIg) and plasma exchange (PE). These produce improvement within a few days after initiation, and so are useful for acute exacerbation including myasthenic crisis or in the perioperative period. High-dose prednisone has been more universally preferred for remission induction, but it acts more slowly than IVIg and PE, commonly only after a delay of several weeks. Slow tapering of steroids after a high-dose pulse offers a method of maintaining the state of remission. However, because of significant side effects, other immunosuppressants (ISs) are frequently added as "steroid-sparing agents". The currently available ISs exert their immunosuppressive effects by three mechanisms: 1) blocking the synthesis of DNA and RNA, 2) inhibiting T-cell activation and 3) depleting the B-cell population. In addition, newer drugs including antisense molecule, tumor necrosis factor alpha receptor blocker and complement inhibitors are currently under investigation to confirm their effectiveness. Until now, the treatment of MG has been based primarily on experience rather than gold-standard evidence from randomized controlled trials. It is hoped that well-organized studies and newer experimental trials will lead to improved treatments.