The comparison of modified minimally invasive and open surgical approaches in the treatment of epithelial thymic tumours

OBJECTIVES

Exploring the efficacy of a modified combined minimally invasive approach in patients with thymoma regardless of myasthenia gravis involvement in contrast to open surgery as the mainstay of treatment.

BACKGROUND

Primary epithelial thymic tumours are rare malignancies of the anterior mediastinum, often present with myasthenia gravis, and with good prognosis when assuming complete surgical resection. We present a modified mini-invasive technique (MIT) that is unique in its extent.

METHODS

Fifty-two patients were included in this retrospective study. Two groups of patients who had undergone different types of surgery were compared using the Mann-Whitney test (ordinal variables) and Fisher's exact test (binary variables). Changes after completing the surgical learning curve were observed.

RESULTS

There was a statistical difference when comparing early Masaoka stages (I‒II) with later stages in favour of the mini-invasive method (p=0.013). The duration of surgery was longer in the mini‑invasive group with a median value of 260 vs 133 min (p=0.001). The analysis of operation times revealed that after overcoming the learning curve period, the duration of surgery decreased (2008‒2012: 297 min; 2013‒2018: 199 min; p=0.005). The systemic complication rate was lower in the mini‑invasive method (26.1 % vs 3.4 %; p=0.035).

CONCLUSION

Our results showed the modified maximal minimally invasive thymectomy to be an effective and safe method, and after overcoming the learning curve, even superior to open surgery in cases with lower tumour stages in terms of its extent (Tab. 3, Fig. 1, Ref. 49).

Monoclonal Antibodies as Neurological Therapeutics

Over the last 30 years the role of monoclonal antibodies in therapeutics has increased enormously, revolutionizing treatment in most medical specialties, including neurology. Monoclonal antibodies are key therapeutic agents for several neurological conditions with diverse pathophysiological mechanisms, including multiple sclerosis, migraines and neuromuscular disease. In addition, a great number of monoclonal antibodies against several targets are being investigated for many more neurological diseases, which reflects our advances in understanding the pathogenesis of these diseases. Untangling the molecular mechanisms of disease allows monoclonal antibodies to block disease pathways accurately and efficiently with exceptional target specificity, minimizing non-specific effects. On the other hand, accumulating experience shows that monoclonal antibodies may carry class-specific and target-associated risks. This article provides an overview of different types of monoclonal antibodies and their characteristics and reviews monoclonal antibodies currently in use or under development for neurological disease.

Jitter Remains Stable Throughout a Single Fiber EMG Session in Healthy and Myasthenic Muscles

Fatigability is the hallmark of myasthenia gravis (MG). It is not clear, however, whether there is an analogous increase in jitter during the course of a single fiber electromyography (SFEMG) session. The individual jitter values of all potentials of 76 normal and 44 myasthenic orbicularis oculi muscles were assigned a rank number according to their temporal order in which they were collected and linear regression was performed to determine if the slope of the regression line was significantly different from zero. Control and MG subjects displayed rather flat linear regression lines with non-significant positive or negative slopes. Accordingly, ROC analysis yielded areas under the curve near 0.5. We conclude that there is no systematic jitter increase during the collection of 20 potential pairs in a typical SFEMG session.

Transmembrane Collagens in Neuromuscular Development and Disorders

Neuromuscular development is a multistep process and involves interactions among various extracellular and transmembrane molecules that facilitate the precise targeting of motor axons to synaptogenic regions of the target muscle. Collagenous proteins with transmembrane domains have recently emerged as molecules that play essential roles in multiple aspects of neuromuscular formation. Membrane-associated collagens with interrupted triple helices (MACITs) are classified as an unconventional subtype of the collagen superfamily and have been implicated in cell adhesion in a variety of tissues, including the neuromuscular system. Collagen XXV, the latest member of the MACITs, plays an essential role in motor axon growth within the developing muscle. In humans, loss-of-function mutations of collagen XXV result in developmental ocular motor disorders. In contrast, collagen XIII contributes to the formation and maintenance of neuromuscular junctions (NMJs), and disruption of its function leads to the congenital myasthenic syndrome. Transmembrane collagens are conserved not only in mammals but also in organisms such as C. elegans, where a single MACIT, COL-99, has been documented to function in motor innervation. Furthermore, in C. elegans, a collagen-like transmembrane protein, UNC-122, is implicated in the structural and functional integrity of the NMJ. This review article summarizes recent advances in understanding the roles of transmembrane collagens and underlying molecular mechanisms in multiple aspects of neuromuscular development and disorders.

Pronounced Ptosis in Myasthenia Gravis-A New Bedside Clinical Sign

We report three cases of myasthenia gravis in whom the asymmetrical ptosis at presentation became more pronounced with the described bedside technique. Pronounced ptosis could be elicited by making the patient speak continuously for up to 2 minutes. Pauses for breathing and natural blinking were allowed. The sign is best elicited in newly diagnosed and treatment-naive patients. The loss of compensation for ptosis by frontalis muscle due to speech-induced fatigue may be responsible for the observed effect. Patients’ symptoms abated on treatment with acetylcholine esterase inhibitors, steroids, and steroid-sparing agents.

Anti-MuSK Positive Myasthenia Gravis with Anti-Lrp4 and Anti-titin Antibodies

In addition to muscle nicotinic acetylcholine receptor (AChR) and muscle-specific kinase (MuSK), low-density lipoprotein receptor (Lrp4) has recently been discovered to be a novel target antigen among patients with seronegative myasthenia gravis (MG). We herein report the findings of a 62-year-old patient who showed positivity for anti-MuSK, anti-Lrp4, and anti-titin antibodies. The patient developed MG crisis following a 10-year history of intermittent double vision with ptosis, and a 7-year history of dropped head. Our detailed clinical, laboratory, and therapeutic descriptions highlight its unique characteristics of anti-MuSK-antibody positive MG accompanied by anti-Lrp4 and anti-titin antibodies.

Clinical Evaluation of the Efficacy and Safety of Co-Administration of Wuzhi Capsule and Tacrolimus in Adult Chinese Patients with Myasthenia Gravis

BACKGROUND

Tacrolimus has been recommended as an effective immunosuppressant for patients with myasthenia gravis (MG), while the high price, variable bioavailability, and narrow therapeutic window restrict its clinical application. Wuzhi capsule (WZC) could improve tacrolimus blood concentration by inhibiting the metabolism of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp). There are few studies focused on the coadministration of WZC and tacrolimus in autoimmune diseases. This study was aimed at quantifying the efficacy and safety of coadministration of WZC and tacrolimus in adult Chinese patients with MG.

METHODS

In this retrospective study, 122 patients with MG on tacrolimus were enrolled. The initial tacrolimus dose was 2 mg/d. Patients with standard initial tacrolimus concentration were classified into group A (standard-dose group). Those failed to reach target concentration were divided into group B (high-dose group) and group C (co-administering WZC group), according to treatment adjustment of increasing tacrolimus dose and co-administration of WZC, respectively. A logistic analysis was used to identify factors associated with clinical outcome. Adverse drug reactions (ADRs) were recorded for safety analysis.

RESULTS

The tacrolimus concentration after coadministration of WZC was remarkably increased. It was higher compared with simply increasing the tacrolimus dose (p<0.001). The multivariate logistic analysis indicated that the baseline quantitative MG score was a predictive factor for clinical outcomes (OR=0.189; 95% CI 0.082-0.436; p<0.001). Fourteen patients (11.5%) reported ADRs after tacrolimus therapy. ADRs incidence was not related to WZC coadministration.

CONCLUSION

The coadministration of WZC and tacrolimus can substantially elevate the tacrolimus concentration. It is a safe and economic treatment for adult Chinese patients with MG. Patients with a worse disease condition tend to present a better clinical outcome after tacrolimus therapy.

Association of polycythemia vera with positive JAK2V617F mutation and myasthenia gravis: A report of two cases

Screening for MG in patients with PV positive for JAK2V617F mutation can help in early diagnosis and treatment, resulting in a significant reduction in morbidity and mortality.

Thymomatous myasthenia gravis: 10-year experience of a single center

OBJECTIVES

To summarize the clinical features of thymomatous myasthenia gravis (T-MG), examine the association between MG and thymoma, and identify the related factors or predictors for long-term prognosis of T-MG.

METHODS

A retrospective, observational study was conducted on 100 patients with T-MG and 96 patients with non-T-MG (NT-MG) between January 1, 2009 and December 31, 2019. The baseline characteristics were recorded for each patient. Logistic regression was used to measure the association between all clinical variables and T-MG prognosis.

RESULTS

Between the T-MG and NT-MG groups, age at onset (45.66 ± 11.53 years vs 39.06 ± 14.39 years); age >40 years (72.0% vs. 40.6%); AChR-Ab positive rate (100.0% vs. 83.3%); Myasthenia Gravis Foundation of America (MGFA) classification at the worst condition (≥grade III, 61.0% vs. 33.0%); thyroid dysfunction (7.0% vs. 20.8%); and outcome (complete stable remission + pharmacologic remission + improvement, 74.0% vs. 93.7%) were statistically significant (P < .05). Presence of thymoma (OR = 0.196, 95%CI = 0.076-0.511, P = .001) was a risk factor for MG. Male sex, post-operative complications, higher grade of MGFA classification, and thymoma Masaoka-Koga pathological stage were risk predictors for long-term prognosis of T-MG (P < .1). Use of preoperative anticholinesterase drugs (OR = 5.504, 95%CI = 1.424-21.284, P = .013) was identified as an independent predictor for T-MG.

CONCLUSION

T-MG is clinically different from NT-MG, and thymoma is considered a risk factor for MG. Preoperative anticholinesterase drug use is a protective factor for long-term prognosis of T-MG. A comprehensive understanding of the characteristics of T-MG will likely help improve its prognosis.

The feasibility of quantitative MRI of extra-ocular muscles in myasthenia gravis and Graves' orbitopathy

Although quantitative MRI can be instrumental in the diagnosis and assessment of disease progression in orbital diseases involving the extra-ocular muscles (EOM), acquisition can be challenging as EOM are small and prone to eye-motion artefacts. We explored the feasibility of assessing fat fractions (FF), muscle volumes and water T2 (T2_water ) of EOM in healthy controls (HC), myasthenia gravis (MG) and Graves' orbitopathy (GO) patients. FF, EOM volumes and T2_water values were determined in 12 HC (aged 22-65 years), 11 MG (aged 28-71 years) and six GO (aged 28-64 years) patients at 7 T using Dixon and multi-echo spin-echo sequences. The EOM were semi-automatically 3D-segmented by two independent observers. MANOVA and t-tests were used to assess differences in FF, T2_water and volume of EOM between groups (P < .05). Bland-Altman limits of agreement (LoA) were used to assess the reproducibility of segmentations and Dixon scans. The scans were well tolerated by all subjects. The bias in FF between the repeated Dixon scans was -0.7% (LoA: ±2.1%) for the different observers; the bias in FF was -0.3% (LoA: ±2.8%) and 0.03 cm³ (LoA: ± 0.36 cm³ ) for volume. Mean FF of EOM in MG (14.1% ± 1.6%) was higher than in HC (10.4% ± 2.5%). Mean muscle volume was higher in both GO (1.2 ± 0.4 cm³ ) and MG (0.8 ± 0.2 cm³ ) compared with HC (0.6 ± 0.2 cm³ ). The average T2_water for all EOM was 24.6 ± 4.0 ms for HC, 24.0 ± 4.7 ms for MG patients and 27.4 ± 4.2 ms for the GO patient. Quantitative MRI at 7 T is feasible for measuring FF and muscle volumes of EOM in HC, MG and GO patients. The measured T2_water was on average comparable with skeletal muscle, although with higher variation between subjects. The increased FF in the EOM in MG patients suggests that EOM involvement in MG is accompanied by fat replacement. The unexpected EOM volume increase in MG may provide novel insights into underlying pathophysiological processes.

Possible implications of dysregulated nicotinic acetylcholine receptor diffusion and nanocluster formation in myasthenia gravis

Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles. The classical form of this autoimmune disease is characterized by the presence of antibodies against the most abundant protein in the neuromuscular junction, the nicotinic acetylcholine receptor. Other variants of the disease involve autoimmune attack of non-receptor scaffolding proteins or enzymes essential for building or maintaining the integrity of this peripheral synapse. This review summarizes the participation of the above proteins in building the neuromuscular junction and the destruction of this cholinergic synapse by autoimmune aggression in myasthenia gravis. The review also covers the application of a powerful biophysical technique, superresolution optical microscopy, to image the nicotinic receptor in live cells and follow its motional dynamics. The hypothesis is entertained that anomalous nanocluster formation by antibody crosslinking may lead to accelerated endocytic internalization and elevated turnover of the receptor, as observed in myasthenia gravis.

The epidemiology of myasthenia gravis

Neuromuscular junction (NMJ) disorders include several dysfunctions that ultimately lead to muscle weakness. Myasthenia gravis (MG) is the most prevalent NMJ disorder with a highly polymorphic clinical presentation and many different faces. Being an autoimmune disease, MG correlates with the presence of detectable antibodies directed against the acetylcholine receptor, muscle-specific kinase, lipoprotein-related protein 4, agrin, titin, and ryanodine in the postsynaptic membrane at the NMJ. MG has become a prototype serving to understand both autoimmunity and the function of the NMJ better. The aim of this review is to synthesize some of the epidemiological data available. Epidemiological data regarding MG are important for postulating hypotheses regarding its etiology and facilitating the description of MG subtypes. Thus, adequate documentation through broad databases is essential. The incidence and prevalence of MG reported around the globe have been rising steadily and consistently over the past decades. Ethnic aspects, gender-related differences, and environmental risk factors have been described, implying that these might contribute to a specific phenotype, further suggesting that MG may be considered an umbrella term that covers several clinical entities.

Evaluating an In-House Cell-Based Assay for Detecting Antibodies Against Muscle-Specific Tyrosine Kinase in Myasthenia Gravis

Background and Purpose

Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cell-based assay (CBA) to detect MuSK Abs.

Methods

A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA).

Results

The MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen's kappa=0.880, p<0.001) and ELISA (Cohen's kappa=0.982, p<0.001).

Conclusions

The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.

Myasthenia Gravis and Myeloproliferative Neoplasms - Mere Association or Paraneoplastic Neurologic Syndrome: A Mini-Review

Myasthenia Gravis (MG) is a rare neurological condition characterized by muscle weakness that worsens after use. Myeloproliferative Neoplasms (MPNs) are disorders due to stem-cell hyperplasia characterized by an increased peripheral blood cell count, overactive bone marrow, and proliferation of mature hematopoietic cells. MPNs may be Philadelphia (Ph) chromosome-positive or Negative .A systematic review of case reports was conducted by searching PubMed, Scopus, and Google scholar to identify case reports in which there is an association between MG and MPN and know whether MG can be considered a possible neurological paraneoplastic syndrome in patients with MPNs. A total of 13 cases of MPNs associated with MG were identified. The most common type of MPN associated with MG was chronic myeloid leukemia (CML) (10 out of 13 patients).  In most of the patients, MG symptoms appeared after a diagnosis of MPN was made. Considering that 10 out of the 13 patients in our cohort had positive auto-antibodies though only 4 of them had thymic hyperplasia, we hypothesize that bone marrow proliferation was responsible for the production of autoantibodies in these patients.As the clonal cell population cannot be eliminated entirely in the bone marrow even after treatment with tyrosine kinase inhibitors (TKI) in Ph +ve MPNs and JAK2 inhibitors in Ph -ve MPNS, MG can occur even in patients who are treated with these agents. A high index of suspicion is needed to diagnose it early, and treatment should be initiated immediately with steroids and anticholinergic agents.

Performance of different criteria for refractory myasthenia gravis

BACKGROUND AND PURPOSE

Defining refractory myasthenia gravis is important, as this can drive clinical decision making, for example, by escalating treatments in refractory individuals. There are several definitions of refractory myasthenia, and their performances have not been compared. Having valid and reliable criteria can help select patients in whom more aggressive treatments may be needed.

METHODS

We applied five different refractory myasthenia criteria (Drachman, Mantegazza, Suh, the International Consensus Guideline (ICG), and the randomised controlled trial of eculizumab in refractory, anti-acetylcholine receptor positive, generalised myasthenia gravis (REGAIN), to a cohort of 237 patients. We compared the proportion of refractory patients among different criteria and their scores on disease severity, fatigue, and quality-of-life (QoL) scales. We also assessed the agreement for each criterion between two trained assessors.

RESULTS

The Drachman, Mantegazza, and Suh criteria resulted in high proportions of refractory individuals (40.1%, 39.2%, and 38.8%, respectively), compared with the ICG and REGAIN criteria (9.7% and 3.0%, respectively). Refractory patients by the ICG and REGAIN criteria had worse disease severity, QoL, and fatigue scores, compared with patients classified as refractory by other criteria. All criteria had high agreement between raters (between 70% and 100%).

CONCLUSIONS

There is high variability in the proportion of refractory myasthenia gravis patients depending on the criteria used, with ICG and REGAIN criteria capturing patients with worse disease severity. This reflects conceptual differences as to what refractory means. Further multicenter studies are needed to determine appropriate criteria for refractory myasthenia gravis.

[Eclizumab in the treatment of myasthenia gravis crisis complicating invasive thymoma: a case study of efficacy]

A 40-year-old male patient was diagnosed with invasive thymoma and myasthenia gravis in 2015. In 2016 and 2017, he experienced myasthenic crises, with an increase in size of invasive thymoma. In 2018, he received chemotherapy for the invasive thymoma. After 2 months, his symptoms rapidly progressed to myasthenic crisis with severe bulbar and respiratory symptoms, despite the significant effect of chemotherapy for the thymoma. High-dose corticosteroid, multiple plasma exchanges, and intravenous immunoglobulin did not improve the symptoms. Thus, eculizumab was administered, resulting in an improvement in his conditions. To our knowledge, this is the first report showing that eculizumab may improve myasthenic crisis with invasive thymoma.

Reduced plasmablast frequency is associated with seronegative myasthenia gravis

BACKGROUND

The immunopathology of autoimmune seronegative myasthenia gravis (SN MG) is poorly understood. Our objective was to determine immune profiles associated with a diagnosis of SN MG.

METHODS

We performed high-dimensional flow cytometry on blood samples from SN MG patients (N = 68), healthy controls (N = 46), and acetylcholine receptor antibody (AChR+) MG patients (N = 27). We compared 12 immune cell subsets in SN MG to controls using logistic modeling via a discovery-replication design. An exploratory analysis fit a multinomial model comparing AChR+ MG and controls to SN MG.

RESULTS

An increase in CD19⁺ CD20^- CD38^hi plasmablast frequencies was associated with lower odds of being a SN MG case in both the discovery and replication analyses (discovery P-value = .0003, replication P-value = .0021). Interleukin (IL) -21 producing helper T cell frequencies were associated with a diagnosis of AChR+ MG (P = .004).

CONCLUSIONS

Reduced plasmablast frequencies are strongly associated with a SN MG diagnosis and may be a useful diagnostic biomarker in the future.

Outcome Measures in Clinical Trials of Patients With Myasthenia Gravis

Myasthenia gravis (MG) is a heterogeneous disorder whose clinical presentation ranges from mild ocular deficits to severe widespread weakness. This variance poses a challenge when quantifying clinical deficits. Deficits and symptoms are quantified using standardized clinical scales and questionnaires which are often used as outcome measures. The past decades have seen the development of several validated outcome measures in MG, which are used in clinical trials to obtain regulatory approval. In recent years, emphasis has moved from objective assessments to patient-reported outcomes. Despite a growing body of literature on the validity of the MG-specific outcome measures, several unresolved factors remain. As several novel therapeutics are currently in clinical development, knowledge about capabilities and limitations of outcome measures is needed. In the present paper, we describe the most widely used clinical classifications and scales in MG. We highlight the choice of outcome measures in published and ongoing trials, and we denote whether trial efficacy was reached on these outcomes. We discuss advantages and limitations of the individual scales, and discuss some of the unresolved factors relating to outcome assessments in MG.

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.

Knowledge and perceptions of the COVID-19 pandemic among patients with myasthenia gravis

BACKGROUND

Patients with myasthenia gravis (MG) may be particularly vulnerable during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic due to risk of worsening disease during infection, potential adverse impacts of coronavirus disease 2019 (COVID-19) treatments on neuromuscular transmission, and a limited ability to fight off infection related to immunosuppressive treatments. Our goal is to understand how patients are experiencing the COVID-19 pandemic, including where they receive relevant information, how it has affected medical care, and what measures they use to protect themselves.

METHODS

This is a prospective online survey study at large academic practice. All patients with a neuromuscular junction disorder diagnosis code in the Duke Health System were invited to participate.

RESULTS

One thousand eight hundred and forty eight patients were approached to participate and 75 completed the survey between 16 April 2020 and 28 May 2020. The most frequently used information sources were non-presidential federal government (75%), state government (57%), local healthcare provider (37%), and television news (36%). Non-presidential federal government (80%), local healthcare providers (55%), state government (33%), and patient support organizations (29%) were considered the most trusted information sources. Thirty-three (44%) of survey responders had attended a telemedicine visit. Patients were taking recommended precautions during the pandemic and remained very concerned (69%) about COVID-19. Generalized Anxiety Disorder-7 scores were moderate-severe in 20% of responders.

CONCLUSIONS

Healthcare providers, the government, and patient organizations play a critical role in communicating with the MG patient community. Use of targeted messaging strategies by these groups to convey accurate information may increase effectiveness and lead to more informed patients with reduced anxiety.

Concomitant Immunosuppressive Therapy Use in Eculizumab-Treated Adults With Generalized Myasthenia Gravis During the REGAIN Open-Label Extension Study

Introduction: Chronic, broad-spectrum immunosuppressive therapy (IST) can be associated with side effects in many people with generalized myasthenia gravis (gMG), and treatment guidelines recommend that the IST dose be tapered once patients achieve a stable treatment response. We therefore examined IST use in eculizumab-treated patients with refractory gMG.

Methods: The REGAIN open-label extension (OLE) enrolled 117 adults with refractory anti-acetylcholine receptor antibody-positive gMG who had completed the 6-month, randomized, double-blind, placebo-controlled REGAIN study of eculizumab. Eligible patients had received ≥2 ISTs for ≥1 year or ≥1 IST with intravenous immunoglobulin or plasma exchange ≥4 times in 1 year, without symptom control. During REGAIN, changes in concomitant MG therapies were not permitted; during the OLE, they were permitted at the investigators' discretion. Participants received eculizumab 1,200 mg every 2 weeks for up to 4 years; concomitant prednisone and related corticosteroids (PRED), azathioprine (AZA), and mycophenolate mofetil (MMF) use was recorded. Changes in MG Activities of Daily Living and Quantitative MG total scores, MG exacerbations, and adverse events were also recorded.

Results: At last OLE assessment, 88.0% (103/117) of participants were using ≥1 IST vs. 98.3% (115/117) at OLE baseline. During the OLE, 76.9% (90/117) of patients experienced a total of 719 IST changes. Almost half of participants [48.7% (57/117)] stopped or decreased ≥1 IST owing to MG symptom improvement, representing 38.9% (280/719) of all changes. In patients who decreased and/or stopped ≥1 IST, mean daily doses of PRED, AZA, and MMF decreased between OLE baseline and last assessment by 60.8% [standard deviation (SD), 28.07; P < 0.0001], 89.1% (SD, 25.77; P < 0.0001), and 56.0% (SD, 32.99; P < 0.0001), respectively. Improved clinical outcomes were observed with eculizumab regardless of IST changes during the OLE, and eculizumab's safety profile was similar in patients who used PRED, AZA, and MMF.

Conclusions: Use of ISTs by patients with previously refractory gMG decreased during eculizumab treatment in the REGAIN OLE. Clinical improvements with eculizumab were maintained by patients in all groups, including those who decreased and/or stopped concomitant ISTs.

Trial registration:www.clinicaltrials.gov: NCT01997229, NCT02301624.

Therapeutic efficacy and immunoregulatory effect of Qiangji Jianli Capsule for patients with myasthenia gravis: Study protocol for a series of randomized, controlled N-of-1 trials

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease in which antibodies directly target components of the neuromuscular junction, causing neuromuscular conduction damage that leads to muscle weakness. The current pharmaceutical treatment for MG is still not ideal to address the problems of disease progression, high recurrence rate, and drug side effects. Clinical observations suggest that traditional Chinese medicine (TCM) can strengthen immunity and improve symptoms of MG patients, delay the progression of the disease, reduce or even prevent the need for immunosuppressive therapy when used in combination with acetylcholinesterase inhibitors or low-dose prednisone, as well as improve the quality of life of patients. The Qiangji Jianli Capsule (QJC) is a combination of medicinal herbs which is used in traditional Chinese medicine. Since MG is a rare disorder, randomized controlled trials comparing large cohorts are difficult to conduct. Therefore, we proposed to aggregate data from a small series of N-of-1 trials to assess the effect of the Chinese medical prescription QJC, which strengthens the spleen and nourishes Qi, as an add-on treatment for MG with spleen and stomach Qi deficiency syndrome.

METHODS AND ANALYSIS

Single-center, randomized, double-blind, multiple crossover N-of-1 studies will compare QJC versus placebo in 5 adult MG patients with spleen and stomach Qi deficiency syndrome. Patients will undergo 3 cycles of two 4-week intervention periods. According to the treatment schedule, patients will continue to be treated with pyridine bromide tablets, prednisone acetate, tablets and/or tacrolimus capsules throughout the entire trial. Each period consisting of 4-week oral add-on treatment with QJC will be compared with 4-week add-on treatment with a placebo. The primary endpoints are quantitative myasthenia gravis (QMG) test; measurement of the amount of Treg cells and cytokines such as interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-17A (IL-17A), and transforming growth factor-β (TGF-β); and corticosteroid or immunosuppressive agent dosage. Secondary outcome measures: Clinical: Evaluation of the effect of TCM syndromes; MG-activities of daily living (MG-ADL) scales; adverse events.

ETHICS AND DISSEMINATION

This study was approved by The First Affiliated Hospital of Guangzhou University of Chinese Medicine (GZUCM), No. ZYYECK[2019]038. The results will be published in a peer-reviewed publication. Regulatory stakeholders will comment on the suitability of the trial for market authorization and reimbursement purposes. Trial registration: Chinese Clinical Trial Register, ID: ChiCTR2000033516. Registered on 3 June 2020, http://www.chictr.org.cn/showprojen.aspx?proj=54618.

Complement Inhibition for the Treatment of Myasthenia Gravis

Generalized myasthenia gravis (gMG) is a rare autoimmune disorder affecting the neuromuscular junction (NMJ). Approximately 80-90% of patients display antibodies directed against the nicotinic acetylcholine receptor (AChR). A major drive of AChR antibody-positive MG pathology is represented by complement activation. The role of the complement cascade has been largely demonstrated in patients and in MG animal models. Complement activation at the NMJ leads to focal lysis of the post-synaptic membrane, disruption of the characteristic folds, and reduction of AChR. Given that the complement system works as an activation cascade, there are many potential targets that can be considered for therapeutic intervention. Preclinical studies have confirmed the efficacy of complement inhibition in ameliorating MG symptoms. Eculizumab, an antibody directed towards C5, has recently been approved for the treatment of AChR antibody-positive gMG. Other complement inhibitors, targeting C5 as well, are currently under phase III study. Complement inhibitors, however, may present prohibitive costs. Therefore, the identification of a subset of patients more or less prone to respond to such therapies would be beneficial. For such purpose, there is a critical need to identify possible biomarkers predictive of therapeutic response, a field not yet sufficiently explored in MG. This review aims to give an overview of the complement cascade involvement in MG, the evolution of complement-inhibiting therapies and possible biomarkers useful to tailor and monitor complement-directed therapies.