The D uke myasthenia gravis clinic registry: I . D escription and demographics

Epidemiology of paraneoplastic neurologic syndromes

Paraneoplastic neurologic syndromes (PNS), initially depicted as seemingly cryptic remote manifestations of malignancy, were first described clinically in the early 20th century, with pathophysiologic correlates becoming better elucidated in the latter half of the century. There remain many questions not only about the pathophysiology but also regarding the epidemiology of these conditions. The continuous discovery of novel autoantigens and related neurologic disease has broadened the association in classical PNS to include conditions such as paraneoplastic cerebellar degeneration. It has also brought into focus several other neurologic syndromes with a putative neoplastic association. These conditions are overall rare, making it difficult to capture large numbers of patients to study, and raising the question of whether incidence is increasing over time or improved identification is driving the increased numbers of cases. With the rise and increasing use of immunotherapy for cancer treatment, the incidence of these conditions is additionally expected to rise and may present with various clinical symptoms. As we enter an era of clinical trial intervention in these conditions, much work is needed to capture more granular data on population groups defined by socioeconomic characteristics such as age, ethnicity, economic resources, and gender to optimize care and clinical trial planning.

Ravulizumab in Myasthenia Gravis: A Review of the Current Evidence

The terminal complement C5 inhibitor ravulizumab was engineered from the humanized monoclonal antibody eculizumab to have an extended half-life and duration of action. It binds to human terminal complement protein C5, inhibiting its cleavage into C5a and C5b, thus preventing the cascade of events that lead to architectural destruction of the postsynaptic neuromuscular junction membrane by the membrane attack complex, and consequent muscle weakness in patients with anti-acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG). The 26-week randomized, placebo-controlled period (RCP) of the phase 3 CHAMPION MG study demonstrated the rapid efficacy of ravulizumab in reducing MG symptoms. Weight-based dosing of ravulizumab every 8 weeks provided sustained efficacy, in terms of patient-reported (Myasthenia Gravis-Activities of Daily Living) and clinician-reported (Quantitative Myasthenia Gravis) endpoints in patients with anti-AChR antibody-positive gMG. Pharmacokinetic and pharmacodynamic analyses showed therapeutic serum ravulizumab concentrations (>175 µg/mL) were achieved immediately after the first dose and were maintained throughout 26 weeks, irrespective of patient body weight; inhibition of serum free C5 was immediate, complete (<0.5 μg/mL), and sustained in all patients. Interim results from the open-label extension (OLE) showed that after 60 weeks, efficacy was maintained in patients continuing on ravulizumab. Rapid and sustained improvements in efficacy, similar to those seen in patients initiating ravulizumab in the RCP, were observed after initiation of ravulizumab treatment in patients who switched from placebo in the RCP to ravulizumab in the OLE. The findings from the RCP and OLE support ravulizumab's favorable safety profile. In conclusion, ravulizumab has a simple weight-based administration and long dosing interval. Its targeted mechanism of action without generalized immunosuppression is reflected in its rapid onset of symptom improvement, sustained efficacy and good safety profile in the treatment of patients with anti-AChR antibody-positive gMG.

Pregnancy in Seronegative Myasthenia Gravis: A Single-Center Case Series

INTRODUCTION

The course of double-seronegative myasthenia gravis (DSNMG) during and after pregnancy has not been well described.

OBJECTIVE

To assess the course of DSNMG during pregnancy and within 6 months postpartum.

METHODS

A retrospective cohort study of women with DSNMG seen in the Duke Myasthenia gravis (MG) Clinic after 2003.

RESULTS

Review of the Duke MG Clinic Registry and electronic medical record identified 8 patients who became pregnant after MG onset; the mean age at disease onset was 17.6 (SD = 10.0) years. Increased MG symptoms were observed in the first and third trimester and, most commonly, postpartum in 6 of 18 pregnancies. Except for 1 infant who developed respiratory distress that required neonatal intensive care admission, all the newborns were healthy at birth.

CONCLUSIONS

As in seropositive MG, increased MG symptoms during pregnancy and within 6 months postpartum is also seen in women with DSNMG.

Remission of severe myasthenia gravis after autologous stem cell transplantation

OBJECTIVE

Myasthenia gravis (MG) is an autoantibody-mediated neuromuscular junction disorder involving the acetylcholine receptors on the motor endplate. The safety and response to high-dose chemotherapy (HDIT) and autologous hematopoietic cell transplantation (HCT) were assessed in a patient with severe refractory MG.

METHODS

As part of a pilot study of HDIT/HCT for patients with treatment-resistant autoimmune neurological disorders, a patient with severe refractory MG underwent treatment. After mobilization of hematopoietic stem cells with rituximab, prednisone, and G-CSF, the patient had HDIT consisting of carmustine, etoposide, cytarabine, melphalan, and rabbit antithymocyte globulin, followed by autologous HCT. The effect of treatment on the autoantibody to the acetylcholine receptor (AChR) was assessed.

RESULTS

The patient had been diagnosed with AChR antibody-positive MG 14 years before HDIT/HCT and had failed thymectomy, therapeutic plasma exchange, and multiple immunomodulatory agents. The Myasthenia Gravis Foundation of America (MGFA) clinical classification was IVb before HDIT/HCT. She tolerated HDIT/HCT well and started to improve clinically within days of treatment. At both 1 and 2 years after HDIT/HCT, patients remained symptom-free. After HDIT/HCT, AChR-binding autoantibodies persisted, and the relative frequency of immune cell subtypes shifted.

INTERPRETATION

HDIT/HCT induced a complete response of disease activity in a patient with severe refractory MG. This response may suggest that a cell-mediated etiology may be a significant contributing factor in refractory MG cases. A phase 2 clinical trial is warranted to establish if HDIT/HCT can be an effective therapy for severe refractory MG and to gain a further understanding of disease pathogenesis.

Therapeutic and prognostic features in myasthenia gravis patients followed in a tertiary neuromuscular diseases center in Turkey

Introduction

In this study, we aim to evaluate the treatment responses and prognostic characteristics of Myasthenia Gravis (MG) patients followed in a tertiary neuromuscular diseases center in Turkey.

Methods

One hundred seventy four MG patients (between years 2011 and 2022) in Antalya, Turkey were diagnosed, and evaluated on a classification of MG was based on Myasthenia. Gravis Foundation of America (MGFA) clinical classification. Exclusion of other possible diseases in the differential diagnosis and support by beneficial response to treatment with acetylcholinesterase inhibitors were also taken into consideration.

Results

Mean age of participants was 54.86 (SD = 14.856; min-max = 22-84). Ninety (51.7%) were female. MG was more common in women under the age of 65 (58%) and in men over the age of 65 (64%). Generalized MG was seen in 75.3% of the patients. Anti-AChR positivities were detected in 52.3%, Anti-MuSK positivity in 4.6%, and seronegativity in 22.4%. Thymoma was detected in nearly 9.8% and thymectomy was performed in 28.7 percent. Most of the patients (57.5%) were using corticosteroids. Azathioprine was used by 39% and mycophenolate mofetil by 10.3% of patients. Mortality was higher and disease was more severe in late-onset (>50 years) MG patients (especially in the COVID-19 pandemic). Eight patients (four women, four men, mean age 75.5 years) died during follow-up. None of them died due to myasthenic worsening, two died due to malignancy and two due to infection. During the COVID pandemic, 16 patients (9.2%) had COVID infection. Four patients died due to COVID-19 infection, these four patients had serious comorbidities, and three of them were elderly (>75 years).

Conclusion

In conclusion, MG is more common in women between the ages of 20-40 and in men over the age of 65. The use of corticosteroids was more common under the age of 50, and the use of non-steroidal immunosuppressant agents was more common over the age of 50. Thymectomy is still an important supportive treatment approach in anti-AChR positive and seronegative generalized patients under 50 years of age. IVIG and plasmapheresis are effective treatments during acute exacerbations and bridging periods of treatments. Specific treatments are needed especially for resistant group of patients.

The Duke Myasthenia Gravis Clinic Registry: II. Analysis of outcomes

INTRODUCTION/AIMS

The Duke Myasthenia Gravis (MG) Clinic Registry contains comprehensive physician-derived data on patients with MG seen in the Duke MG Clinic since 1980. The aim of this study was to report outcomes in patients seen in the clinic and treated according to the International Consensus Guidance statements.

METHODS

This is a retrospective cohort study of patients initially seen after 2000 and followed for at least 2 years in the clinic. Treatment goal (TG) was defined as achieving MGFA post-intervention status of "minimal manifestations" or better; PIS was determined by the treating neurologist. Time-to-event analysis, including Cox proportional hazards modeling, was performed to assess the effect of sex, acetylcholine receptor antibody (AChR-Ab) status, age at disease onset, distribution (ocular vs generalized), thymectomy, and thymoma on the time to achieve TG.

RESULTS

Among the 367 cohort patients, 72% achieved TG (median time less than 2 years). A greater proportion of patients with AChR-Abs and thymectomy achieved TG and they did so sooner than patients without these antibodies or thymectomy. Otherwise, there were no significant differences in these findings within the tested subgroups. The disease duration at the first Duke Clinic visit was shorter in patients who achieved TG than in those who did not.

DISCUSSION

These results demonstrate outcomes that can be achieved in patients with MG treated according to the current Consensus Guidance statements. Among other things, they can be used to determine the added value and potential role of new treatment modalities developed since 2018.

Current management of myasthenia gravis in Belgium: a single-center experience

INTRODUCTION

As new treatments are becoming available for patients with myasthenia gravis (MG), it is worth reflecting on the actual status of MG treatment to determine which patients would most likely benefit from the new treatments.

METHODS

We reviewed the clinical files of all MG patients seen at the Department of Neurology of the Antwerp University Hospital during the years 2019, 2020 and 2021.

RESULTS

163 patients were included. Age at diagnosis varied from the first to the eighth decades, with a peak of incidence from 60 to 70 years for both genders, and an additional peak from 20 to 30 years in women. Diplopia and ptosis were by far the most common onset symptom. At maximum disease severity, 24% of the patients still had purely ocular symptoms and 4% needed mechanical ventilation. 97% of the patients received a treatment with pyridostigmine and 68% with corticosteroids, often in combination with immunosuppressants. More than half reported side effects. At the latest visit, 50% of the patients were symptom-free. Also, half of the symptomatic patients were fulltime at work or retired with no or mild limitations in daily living. The remaining patients were working part-time, on sick leave, or retired with severe limitations.

DISCUSSION AND CONCLUSION

The majority of MG patients are doing well with currently available treatments, but often at the cost of side effects in the short and in the long term. A significant group is in need of better treatments.

One-year follow-up of disease burden and medication changes in patients with myasthenia gravis: From the MG Patient Registry

INTRODUCTION/AIMS

We studied the progression of myasthenia gravis (MG) disease burden and medication adjustment among MG Patient Registry participants.

METHODS

Participants diagnosed with MG (age ≥18 years), registered between July 1, 2013 and July 31, 2018 and completing both 6- and 12-month follow-up surveys, were included in this investigation. Participants were grouped into high-burden (Myasthenia Gravis Activity of Daily Living scale [MG-ADL] score ≥6) and low-burden (MG-ADL <6) groups based on MG-ADL scores at enrollment. Demographics and disease history were compared between groups. MG-ADL score change and medication changes (escalation, no change, de-escalation) between enrollment and 12-month follow-up were compared between groups. Minimal symptom expression (MSE, MG-ADL <2) at 12 months was compared between groups. Logistic regression analysis was performed to study factors associated with MSE at 12 months.

RESULTS

In total, 520 participants (56% female) were included in high-burden (n = 248) and low-burden (n = 272) groups. Those in the high-burden group were more likely to be younger, female, and have shorter disease duration. At 12 months, MSE was achieved in 6% of the high-burden group and newly achieved (42 of 201, 21%) or maintained (52 of 71, 73%) in the low-burden group. In the multivariable analysis, being in the high-burden group and use of pyridostigmine were associated with less likelihood of MSE, whereas MG-ADL score improvement (>2 or >20%) at 6 months significantly increased the likelihood of achieving MSE at 12 months (P = .0004).

DISCUSSION

In both groups, but more so in the high-burden group, patients infrequently achieved MSE after 1 year of MG treatment. Baseline low disease burden, improvement at 6 months and no pyridostigmine use were associated with a higher likelihood of MSE at 12 months.

Differences in immunophenotypes between myasthenia gravis patients with and without thyroid antibodies

INTRODUCTION/AIMS

Immunophenotypes are related to the therapeutic efficacy of specific immunomodulating agents in patients with myasthenia gravis (MG), but the relationship of immunophenotype to the presence or absence of thyroid antibodies is unknown. This study aims to evaluate differences in the immunophenotypes between MG patients with and without thyroid antibody (TAb) positivity to provide insight for future targeted immunotherapies.

METHODS

This retrospective observational study included 48 MG patients with acetylcholine receptor antibody (AchR-Ab), of which 15 (31.25%) were TAb positive. Ocular MG (OMG) was defined as ocular-only manifestations for the duration for which records were available. Peripheral lymphocyte subpopulations were measured by flow cytometry.

RESULTS

TAb positive patients appeared to have a higher prevalence of OMG than TAb negative patients (53.33% vs. 24.24%, P  = 0.048). Percentages of B cells (mean difference (MD) = 6.16, 95% confidence interval (CI): 1.91 to 10.40, P = 0.007) and CD8 + CD28+ cells (MD = 15.14, 95%CI: 5.17 to 25.11, P  = 0.013) were higher in TAb positive patients than those in TAb negative patients, while AChR-Ab titers (MD = -6.49 nmol/L, 95%CI: -9.29 to -3.70, P  < 0.001), percentages of T cells (MD = -6.43, 95%CI: -11.92 to -0.94, P = 0.023), CD3 + HLA-DR+ cells (MD = -6.47, 95%CI: -12.31 to -0.63, P  = 0.031) and CD8+ T cells (MD = -6.60, 95%CI: -9.86 to -3.34, P < 0.001) were lower.

DISCUSSION

The immunophenotypes of MG patients with and without TAb positivity were significantly different, suggesting that their sensitivity to immunotherapy may be different. Further studies focused on differences between TAb positive and TAb negative MG patients in their responses to specific immunotherapies are needed to support our exploratory findings. This article is protected by copyright. All rights reserved.

Age at sampling and sex distribution of AChRAb vs. MuSKAb myasthenia gravis in a large Greek population

OBJECTIVE

Myasthenia gravis (MG) is a typical B-cell-mediated neuromuscular junction disease that can be classified into seropositive and seronegative subtypes. Association of patients' age at sampling and sex with the two major seropositive MG subcategories, i.e., MGs linked to antibodies directed against the acetylcholine receptor (AChRAb) and against the muscle-specific kinase (MuSKAb), has not been compared in a large population.

METHODS

We performed a retrospective analysis of samples from patients with MG in Greece who underwent neurochemical diagnostic evaluation between January 2, 2013, and August 31, 2016.

RESULTS

Overall, 1620 adult (623 male and 997 female patients; male-to-female ratio = 0.62) and 51 pediatric patients were found to be seropositive for MG. The distributions in both male and female patients were bimodal in the total and AChRAb MG cases but not in the total MuSKAb MG cases. Significant differences in the age at sampling distribution between the male and female adult patients were observed only in the AChRAb MG subtype. Significant differences between the AChRAb and MuSKAb MG categories were noted in the mean age values (60.10 and 51.49 years, respectively, for female and 65.69 and 56.19 years, respectively, for male adult patients).

CONCLUSION

Our findings confirm an uneven profile of age at sampling and sex between the AChRAb and MuSKAb MG cases in a large population. Future mechanistic studies can elucidate the cause of these differences. Moreover, clinical studies can explore how such differences can affect MG treatment and prognosis.