Clinical Experience with Eculizumab in Treatment-Refractory Acetylcholine Receptor Antibody-Positive Generalized Myasthenia Gravis

Measuring Human Memory B Cells in Autoimmunity Using Enzyme-Linked ImmunoSpot

The measurement of serum antibodies that specifically recognize self-antigens is a critical diagnostic in autoimmunity. A limitation of such an approach is sensitivity to detect the antibody, particularly when abundant self-antigens in the body may bind and sequester circulating specific antibodies. The presence of specific memory B cells (Bmem) may provide a more sensitive and robust indicator of an autoimmune response, as is suggested for certain anti-viral responses. B cell enzyme-linked ImmunoSpot (ELISPOT) is capable of detecting antigen-specific Bmem cells in blood at the single cell level, following stimulation of peripheral blood mononuclear cells (PBMCs) to expand and differentiate the Bmem cells into functional antibody-secreting cells (ASCs). While this assay has been widely utilized in infectious diseases and vaccination, detection is more difficult for autoantigens due to self-tolerance and specific tissue compartmentalization of immune responses, making autoantigen-specific B cells rare in the circulation. The cycles of re-activation of Bmem cells to become ASCs, that may reflect disease flare-ups in autoimmunity, are not well defined. For several autoimmune diseases (ADs), the targeting of B cells via depleting monoclonal antibodies has proven to be an effective treatment, where Bmem cells are likely being targeted. The measurement of autoantigen-reactive Bmem cells may aid in diagnosis and staging of clinical severity, or be a metric for efficacious treatments, thus providing an additional informative biomarker of ADs. How B cell ELISPOT has been utilized to characterize Bmem cells in human ADs is described here, including the advantages and disadvantages of the assay.

The role of complement in the immunopathogenesis of acetylcholine receptor antibody-positive generalized myasthenia gravis: bystander or key player?

The complement system is a key component of the innate immune system. In antiacetylcholine receptor (AChR) antibody-positive (Ab+) generalized myasthenia gravis (MG), complement activation has long been considered a principal driver of pathology. Understanding the role of complement in AChR-Ab+ generalized MG has gained increasing importance in recent years, as anticomplement drugs have been approved for clinical use or are undergoing phase II/III clinical trials. This review aims to discuss recent and previous findings on the role of complement in AChR-Ab+ MG pathology, including its interaction with pathogenic antibodies and mechanisms beyond the classical pathway activation.

C5 complement inhibition versus FcRn modulation in generalised myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular junctions, leading to fluctuating muscle weakness. While many patients respond well to standard immunosuppression, a substantial subgroup faces ongoing disease activity. Emerging treatments such as complement factor C5 inhibition (C5IT) and neonatal Fc receptor (FcRn) antagonism hold promise for these patients. However, the current landscape is hindered by a paucity of comparative data that is crucial for treatment decisions.

OBJECTIVE

This study aims to compare the effectiveness and safety of C5IT and FcRn antagonists in a real-world setting.

METHODS

A retrospective analysis of 153 MG patients from 8 German specialised MG centres receiving either C5IT (26 eculizumab, 80 ravulizumab) or efgartigimod (47 patients) was conducted. Propensity score matching (PSM) was employed to compare changes in MG-specific outcome parameters within the first 6 months after treatment initiation, along with safety profiles and concomitant MG therapy.

RESULTS

Both treatment strategies led to rapid clinical improvements and substantial reductions in prednisolone doses. However, insufficient response was noted in 20%-49.1% of patients based on Quantitative MG and MG Activities of Daily Living (MG-ADL) scores. We did not identify any new safety concerns. After PSM, 40 patients remained in each group. In both cohorts, reductions in MG-ADL as prespecified primary study endpoint were comparable. Moreover, analyses of secondary outcome parameters demonstrated similar results for C5IT versus FcRn.

CONCLUSION

In contrast to current meta-analyses and indirect comparisons of clinical trial data, our real-world study demonstrates comparable efficacy and safety of C5IT and FcRn antagonism in MG.

New and Emerging Biological Therapies for Myasthenia Gravis: A Focussed Review for Clinical Decision-Making

Myasthenia gravis (MG) is a rare autoimmune disease characterised by exertion-induced muscle weakness that can lead to potentially life-threatening myasthenic crises. Detectable antibodies are directed against specific postsynaptic structures of the neuromuscular junction. MG is a chronic condition that can be improved through therapies, but to date, not cured. Standard treatment has been unchanged for decades and includes symptomatic treatment with acetylcholine-esterase inhibitors and disease-modifying treatment with steroids, steroid-sparing immunosuppressants and thymectomy. Overall, a relevant proportion of patients does not achieve a satisfactory clinical improvement under standard treatment. Additionally, long-term therapy with steroids can cause significant side effects and latency to clinical improvement with standard steroid-sparing immunosuppressants and after thymectomy can take months to years. In recent years, treatment of MG has changed fundamentally due to improved evidence from phase 3 trials and the regulatory approval of complement inhibitors and FcRn inhibitors as add-on treatment options. This provides new optimism for substantially more patients reaching minimal manifestation status and has led to a shift in treatment strategy with more targeted therapies being employed early in the course of the disease, especially in patients with high disease activity. In this focussed review, we provide an overview of the diagnosis, classification and standard treatment of MG, followed by data from randomised controlled trials on the modern drugs already available for therapy and those still in the final stages of clinical development. In the second part, we provide an overview of real-world data for already approved therapies and outline how the availability of new biologicals is changing both clinical decision-making and patient journey.

Eculizumab in refractory myasthenia gravis: a real-world single-center experience

INTRODUCTION

Immunosuppressive treatment is effective in most Myasthenia gravis patients, but 10-15% of patients areconsidered refractory due to inadequate response or intolerance to therapy. Eculizumab, a humanized monoclonalantibody directed against C5 complement protein, was approved in Italy to treat Ab-AchR generalized refractoryMG (rMG) in October 2022.

AIM

We aim to describe a real-world Italian experience in a population of refractory myasthenia gravis patients with oneyear follow up.

METHODS

A retrospective data analysis was conducted on patients with refractory generalized MG treated with eculizumabbetween November 2022 and May 2024. Clinical assessment through specific scales (MG ADL - QMG - MGFA -PIS), rescue, and background therapy was recorded after one, three, six, and twelve months.

RESULTS

21 rMG patients were treated with eculizumab with a medium follow up of 10.4 months and 14 patients had at leastone year follow up. A clinically meaningful reduction in total MG-ADL and QMG scores was achieved in the firstmonth. It was maintained throughout the first, third, sixth, and twelfth month along with concomitant reduction ofimmunosuppressive treatments. A drastic reduction of myasthenic exacerbations and crisis was observed duringfollow up and intravenous immunoglobulin treatment was discontinued in all patients except one. The total dailydose of prednisone was significantly reduced.

DISCUSSION

This single-center real-world study confirmes safety and effectiveness of eculizumab. Eculizumab improved rapidlyall clinical outcome measures, leading to discontinuation of intravenous immunoglobulin treatment and remarkable immunosuppressant-sparing benefits.

US Clinical Practice Experience with Eculizumab in Myasthenia Gravis: Acute Clinical Events and Healthcare Resource Utilization

BACKGROUND AND OBJECTIVE

The terminal complement inhibitor eculizumab is approved in the USA for the treatment of patients with acetylcholine receptor antibody-positive generalized myasthenia gravis (MG). The ELEVATE study aimed to examine clinical-practice outcome data on eculizumab effectiveness in US adults with MG (generalized or ocular). This paper reports the findings on MG exacerbations and crises and associated healthcare resource utilization, and the use of rescue therapy.

METHODS

A retrospective chart review was conducted of US adults with MG who initiated eculizumab. Outcomes assessed for up to 2 years before and after eculizumab initiation included percentages and rates per patient per year (PPPY) of exacerbations and crises (the latter defined as intubation/impending intubation), healthcare resource utilization, and rescue therapy administration.

RESULTS

A total of 119 patients diagnosed with MG were enrolled in the study; 92 patients had ≥ 3 months of data both before and during eculizumab therapy and were included in the analyses. The mean rate of MG exacerbations decreased from 0.385 PPPY before eculizumab initiation to 0.152 PPPY during eculizumab treatment (p = 0.0034); the mean rate of MG crises decreased from 0.411 to 0.056 PPPY (p = 0.0018). Rates of healthcare resource utilization and rescue therapy use also decreased significantly during eculizumab treatment.

CONCLUSIONS

This retrospective chart review analysis provides evidence for a beneficial impact of eculizumab treatment on the incidence of MG exacerbations and crises and associated healthcare resource utilization in clinical practice, and on rescue therapy use. These data further support the therapeutic benefits of eculizumab in patients with MG.

Visualization and characterization of complement activation in acetylcholine receptor antibody seropositive myasthenia gravis

INTRODUCTION/AIMS

There are no blood biomarkers to monitor treatment effects in myasthenia gravis (MG) or studies visualizing the acetylcholine receptor (AChR) antibody-induced membrane attack complex (MAC) at the human muscle membrane. This study aimed to compare levels of complement activation products and native complement components in MG patients and healthy controls (HCs) and to model the AChR antibody-mediated attacks in human muscle cells.

METHODS

We assessed the complement components and activation product levels with enzyme-linked immunosorbent assay and magnetic bead-based sandwich assays in plasma and sera of 23 MG patients and matched HCs. Receiver operator characteristic (ROC) curve analysis evaluated the diagnostic accuracy. Complement levels were correlated with the myasthenia gravis composite (MGC) scores. AChR+ MG modeling in human muscle cells used sera from nine MG patients and three HCs.

RESULTS

MG patients had significantly higher plasma levels of C3a (p < .0001), C5 (p = .0003), and soluble C5b-9 (sC5b-9; p < .0001) than HCs. The ROC curve analysis showed a clear separation between MG patients and HCs for plasma C3a (AUC = 0.9720; p < .0001) and sC5b-9 (AUC = 0.8917, p < .0001). MG patients had higher levels of plasma complement Factor I (FI; p = .0002) and lower properdin levels (p < .0001). The MGC had moderate correlations with plasma Factor B (FB), FI, and Factor H. AChR+ MG patient sera triggered the deposition of MAC and reduced AChRs.

DISCUSSION

We suggest validating plasma C3a and sC5b-9 as blood biomarkers for complement activation in MG. Further, the in vitro study allowed visualization of MAC deposition after applying AChR+ MG sera on human muscle cells.

A real-life experience with eculizumab and efgartigimod in generalized myasthenia gravis patients

INTRODUCTION

Eculizumab, a complement active antibody, and efgartigimod, an Fc fragment that blocks neonatal Fc receptor, are both approved to treat generalized myasthenia gravis (gMG) patients. The objective of this study is to describe the clinical response to both treatments in a real-life setting.

METHODS

We collected baseline and follow-up clinical data using the Myasthenia Gravis-Activities of Daily Living (MG-ADL), and Quantitative Myasthenia Gravis (QMG). We included 63 patients, 32 treated with eculizumab and 31 with efgartigimod. Of the efgartigimod-treated patients, 22 were anti-acetylcholine receptor antibody-positive (AChR-Ab +) and 9 were AChR-Ab- (3 MuSK-Ab + and 6 seronegative).

RESULTS

Both treatments showed similar efficacy relative to the MG-ADL scale reduction (p = 0.237). Efgartigimod had a similar effect on both AChR-Ab + and AChR-Ab- (p = 0.280). Eculizumab was superior to efgartigimod relative to the QMG score reduction for the entire dataset (p = 0.003) and was more likely to achieve a clinical response at the QMG compared to efgartigimod (OR 1.373; p = 0.016). Steroid-sparing effect was higher for eculizumab than efgartigimod ( - 16.7 vs  - 5.2 mg of the baseline daily dose at follow-up; p = 0.001). Mean speed of prednisone reduction was  - 13.1 mg of the daily dose for each month of follow-up for eculizumab-treated patients and  - 3.2 for efgartigimod (p = 0.001). We found three serious events, all not related to treatment in the investigator's opinion. One eculizumab-treated patient experienced a severe pneumonia and died despite treatment.

CONCLUSIONS

Our study provides evidence that eculizumab and efgartigimod can be used in clinical practice to reduce disability in gMG patients. Eculizumab-treated patients had a higher QMG response and steroid sparing effect. Efgartigimod may offer a more flexible schedule due to its cyclical use, no need for vaccination, and efficacy in AChR-Ab- patients.

Expert consensus recommendations for improving and standardising the assessment of patients with generalised myasthenia gravis

BACKGROUND

Regular and consistent disease assessment could provide a clearer picture of burden in generalised myasthenia gravis (gMG) and improve patient care; however, the use of assessment tools in practice lacks standardisation. This modified Delphi approach was taken to review current evidence on assessment tool use in gMG and develop expert-derived consensus recommendations for good practice.

METHODS

A European expert panel of 15 experienced gMG neurologists contributed to development of this consensus, four of whom formed a lead Sub-committee. The PICO (Population, Intervention, Control, Outcomes) framework was used to define six clinical questions on gMG assessment tools, a systematic literature review was conducted, and evidence-based statements were developed. According to a modified Delphi voting process, consensus was reached when ≥70% of the experts rated agreement with a statement as ≥8 on a scale of 1-10.

RESULTS

Eighteen expert- and evidence-based consensus statements based on six themes were developed. Key recommendations include: consistent use of the Myasthenia Gravis Activities of Daily Living score (MG-ADL) across clinical settings, followed by a simple question (e.g., Patient Acceptable Symptom State [PASS]) or scale to determine patient satisfaction in clinical practice; use of a Quantitative Myasthenia Gravis [QMG] or quality of life [QoL] assessment when the MG-ADL indicates disease worsening; and consideration of symptom state to determine the timing and frequency of recommended assessments. Expert panel consensus was reached on all 18 statements after two voting rounds.

CONCLUSIONS

This process provided evidence- and expert consensus-based recommendations for the use of objective and subjective assessment tools across gMG research and care to improve management and outcomes for patients.

Myasthenia Gravis Treatment: From Old Drugs to Innovative Therapies with a Glimpse into the Future

Myasthenia gravis (MG) is a rare autoimmune disease that causes debilitating muscle weakness due to impaired neuromuscular transmission. Since most (about 80-90%) MG patients present autoantibodies against the acetylcholine receptor, standard medical therapy consists of symptomatic treatment with acetylcholinesterase inhibitors (e.g., pyridostigmine). In addition, considering the autoimmune basis of MG, standard therapy includes immunomodulating agents, such as corticosteroids, azathioprine, cyclosporine A, and cyclophosphamide. New strategies have been proposed for the treatment of MG and include complement blockade (i.e., eculizumab, ravulizumab, and zilucoplan) and neonatal Fc receptor antagonism (i.e., efgartigimod and rozanolixizumab). The aim of this review is to provide a detailed overview of the pre- and post-marketing evidence on the five pharmacological treatments most recently approved for the treatment of MG, by identifying both preclinical and clinical studies registered in clinicaltrials.gov. A description of the molecules currently under evaluation for the treatment of MG is also provided.

Refractory generalized myasthenia gravis with myasthenic incomplete ophthalmoplegia successfully treated with eculizumab

Purpose

This is a case of myasthenic incomplete ophthalmoplegia mimicking a partial cranial nerve 3 palsy both subjectively and objectively improving after treatment with eculizumab.

Observations

We chronicle a case of severe generalized myasthenia gravis including myasthenia masquerading as a partial cranial nerve 3 palsy, refractory to pyridostigmine, mycophenolate, prednisone, intravenous immunoglobulin and plasma exchange but responsive to eculizumab.

Conclusions and importance

This case demonstrates ocular and generalized myasthenia gravis refractory to several other therapies but amenable to eculizumab infusions, suggesting this medication may be of significant value in these difficult cases, and should be further explored for refractory ocular myasthenia gravis.

Role of complement in myasthenia gravis

Myasthenia gravis is a prototypic neuroimmune disorder with autoantibodies targeting the acetylcholine receptor complex at the neuromuscular junction. Patients present with mainly ocular muscle weakness and tend to have a generalized muscle weakness later in the clinical course. The weakness can be severe and fatal when bulbar muscles are heavily involved. Acetylcholine receptor antibodies are present in the majority of patients and are of IgG1 and IgG3 subtypes which can activate the complement system. The complement involvement plays a major role in the neuromuscular junction damage and the supporting evidence in the literature is described in this article. Complement therapies were initially studied and approved for paroxysmal nocturnal hemoglobinuria and in the past decade, those have also been studied in myasthenia gravis. The currently available randomized control trial and real-world data on the efficacy and safety of the approved and investigational complement therapies are summarized in this review.

Single count breath test for the evaluation of respiratory function in Myasthenia Gravis: A systematic review

BACKGROUND

Myasthenia gravis (MG) can have a variety of respiratory presentations, ranging from mild symptoms through to respiratory failure. The evaluation of respiratory function in MG can be limited by accessibility to testing facilities, availability of medical equipment, and facial weakness. The single count breath test (SCBT) may be a useful adjunct in the evaluation of respiratory function in MG.

METHOD

A systematic review of the databases PubMed, EMBASE, and the Cochrane Library was conducted from inception to October 2022 in accordance with PRISMA guidelines and was registered on PROSPERO.

RESULTS

There were 6 studies that fulfilled the inclusion criteria. The described method of evaluating SCBT involves inhaling deeply, then counting at two counts per second, in English or Spanish, sitting upright, with normal vocal register, until another breath needs to be taken. The identified studies support that the SCBT has a moderate correlation with forced vital capacity. These results also support that SCBT can assist the identification of MG exacerbation, including via assessment over the telephone. The included studies support a threshold count of ≥ 25 as consistent with normal respiratory muscle function. Although further analysis is needed, the included studies describe the SCBT as a quick bedside tool that is inexpensive and well tolerated.

CONCLUSIONS

The results of this review support the clinical utility of the SCBT in assessing respiratory function in MG and describe the most current and effective methods of administration.

Practical Management for Use of Eculizumab in the Treatment of Severe, Refractory, Non-Thymomatous, AChR + Generalized Myasthenia Gravis: A Systematic Review

Myasthenia gravis (MG) is a rare autoimmune disorder caused by specific autoantibodies at the neuromuscular junction. MG is classified by the antigen specificity of these antibodies. Acetylcholine receptor (AChR) antibodies are the most common type (74–88%), followed by anti-muscle specific kinase (MuSK) and other antibodies. While all these antibodies lead to neuromuscular transmission failure, the immuno-pathogenic mechanisms are distinct. Complement activation is a primary driver of AChR antibody-positive MG (AChR+ MG) pathogenesis. This leads to the formation of the membrane attack complex and destruction of AChR receptors and the postsynaptic membrane resulting in impaired neurotransmission and muscle weakness characteristic of MG. Broad-based immune-suppressants like corticosteroids are effective in controlling MG; however, their long-term use can be associated with significant adverse effects. Advances in translational research have led to the development of more directed therapeutic agents that are likely to alter the future of MG treatment. Eculizumab is a humanized monoclonal antibody that inhibits the cleavage of complement protein C5 and is approved for use in generalized MG. In this review, we discuss the pathophysiology of MG; the therapeutic efficacy and tolerability of eculizumab, as well as the practical guidelines for its use in MG; future studies exploring the role of eculizumab in different stages and subtypes of MG subtypes; the optimal duration of therapy and its discontinuation; the characterization of non-responder patients; and the use of biomarkers for monitoring therapy are highlighted. Based on the pathophysiologic mechanisms, emerging therapies and new therapeutic targets are also reviewed.

Safety and outcomes of eculizumab for acetylcholine receptor-positive generalized myasthenia gravis in clinical practice

INTRODUCTION/AIMS

Safety and outcomes data on eculizumab for generalized myasthenia gravis (gMG) in clinical practice remain limited. Outcomes and concomitant medication use may differ in practice compared with clinical trials. We analyzed the clinical and safety outcomes of patients who received eculizumab at our institutions.

METHODS

Patients with acetylcholine receptor antibody positive (AChR+) gMG, who received ≥1 dose of eculizumab and had ≥1 follow-up before December 10, 2021, were identified. Data were abstracted by chart review. Outcomes included MG Foundation of America Post Intervention Status (MGFA-PIS), Clinical Classification (MGFA-CC), MG-Activities of Daily Living (MG-ADL), concurrent immunomodulatory therapy use, and adverse events.

RESULTS

Twelve patients were included. Mean age at eculizumab initiation was 57.4 y (range, 21-77). Eight had refractory MG. Four had history of thymoma and thymectomy. A mean of 3.2 (range, 2-5) immunomodulatory therapies were previously tried. Mean follow-up duration was 18 mo (range, 2-21.6). Clinical improvement occurred rapidly; MGFA-PIS was improved in 80%, and MGFA-CC improved in 83% at 1 mo. Mean MG-ADL decreased from 8.7 to 2.8 at 1 mo, and remained ≤ 3 $$ \le 3 $$ .5 over 1.5 y. Mean daily prednisone dose decreased from 22.5 mg to 7.2 mg at 1.5 y. Five of 7 patients discontinued maintenance IVIG or PLEX. No patients had meningococcal infections and adverse events were mild.

DISCUSSION

Clinical improvement occurred in most patients after eculizumab initiation, beginning as quickly as 1 mo. Steroids were tapered and maintenance IVIG and PLEX were discontinued in most. Eculizumab had a favorable safety profile even when combined with other immunosuppressants.

Anti-complement Agents for Autoimmune Neurological Disease

In recent years, there has been increasing recognition of the diversity of autoimmune neurological diseases affecting all levels of the nervous system. A growing understanding of disease pathogenesis has enabled us to better target specific elements of the immune system responsible for the cell dysfunction and cell destruction seen in these diseases. This is no better demonstrated than in the development of complement directed therapies for the treatment of complement mediated autoimmune neurological conditions. Herein, we describe the basic elements of the complement cascade, provide an overview of select autoimmune neurological diseases whose pathogenesis is mediated by complement, the effector system of autoantigen bound autoantibodies, and discuss the complement directed therapies trialed in the treatment of these diseases. Several complement-directed therapies have demonstrated benefit in the treatment of autoimmune neurological diseases; we also review the trials resulting in the approval of these therapies for the treatment of AChR Ab-positive myasthenia gravis (MG) and neuromyelitis spectrum disorder. Finally, on the heels of the recent successes described, we discuss possibilities for the future, including additional targeted therapies with greater ease of administration, improved risk profiles, and other possible uses for therapeutics targeting elements of the complement cascade.

Eculizumab treatment for myasthenia gravis subgroups: 2021 update

Eculizumab is a recombinant humanized monoclonal antibody that targets the complement protein C5, inhibiting its cleavage into C5a and C5b and ultimately preventing the formation of C5b-9 membrane attack complex (MACs), thereby protecting the neuromuscular junction from the damage of complement activation. In 2017, eculizumab became the second FDA-approved medication for AchR-positive generalized myasthenia gravis (gMG) patients based on the successful results of a randomized, double-blinded, placebo-controlled, phase 2, phase 3 study (the REGAIN trial) and its open-label extension study. Despite the efficacy of eculizumab in treating AchR antibody-positive refractory gMG was demonstrated in the REGAIN study, there is few information on its efficacy in other subgroup of MG patients including seronegative MG, thymoma-associated MG and MG crisis. This narrative review summarizes current clinical studies of eculizumab in these refractory gMG patients, with a focus on the therapeutic efficacy and tolerability in different subgroup of MG.

Efficacy and Safety of Immunotherapies in Refractory Myasthenia Gravis: A Systematic Review and Meta-Analysis

Introduction: Approximately 10–20% of patients WITH myasthenia gravis (MG) are refractory to conventional immunotherapies. The purpose of this study was to conduct a systematic review and meta-analysis to explore the optimal therapies for refractory MG.

Method: Correlative studies were performed through a search in PubMed, Cochrane Library, and Embase databases. The primary outcome was defined by changes in the quantitative myasthenia gravis score (QMG). Secondary outcomes were defined by the Myasthenia Gravis Activities of Daily Living Scale (MG-ADL), Myasthenia Gravis Foundation of America (MGFA) post intervention status, adverse events, and disease exacerbation after treatment.

Result: A total of 16 studies were included with 403 patients with refractory MG on therapies with rituximab, eculizumab, tacrolimus, and cladribine. Therapeutic efficacy of rituximab and eculizumab was identified with an estimated reduction in QMG score (4.158 vs. 6.928) and MG-ADL (4.400 vs. 4.344), respectively. No significant changes were revealed in efficacy or exacerbation density between the two independent therapeutic cohorts. The estimated adverse event density of eculizumab was more significant than that in the rituximab group (1.195 vs. 0.134 per patient-year), while the estimated serious event density was similar.

Conclusion: The efficacy and safety of rituximab and eculizumab have been approved in patients with refractory MG. Rituximab had a superior safety profile than eculizumab with a lower incidence of adverse events.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021236818, identifier CRD42021236818.

Clinical Efficacy and Safety of Eculizumab for Treating Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune disease primarily mediated by acetylcholine receptor antibodies (AChR-Ab), cellular immune dependence, and complement system involvement. Since the AChR on the postsynaptic membrane is destroyed by an immune attack, sufficient endplate potential cannot be generated, resulting in the development of a synaptic transmission disorder at the neuromuscular junction and in muscle weakness. The role of the complement system in MG has been demonstrated in animal models and clinical tests, and it has been determined that complement inhibition in patients with MG can prevent disease induction and reverse its progression. Eculizumab is a humanized monoclonal antibody that inhibits the cleavage of complement protein C5 and prevents autoimmune damage; additionally, it has received subsequent approval by the Federal Drug Administration of the United States for MG treatment. However, various concerns regarding the use of eculizumab persist. In this review, we have discussed the treatment time, cost effectiveness, long-term efficacy, and tolerability of eculizumab for MG treatment. We have also summarized historical information and have presented perspectives on this new therapeutic modality.

Clinical experience with maintenance therapeutic plasma exchange in refractory generalized myasthenia gravis

BACKGROUND

Despite the availability of several immunomodulatory therapies, about 20% of myasthenia gravis (MG) patients remain refractory to conventional treatments. There is limited evidence to support the use of maintenance therapeutic plasma exchange (TPE) therapy for refractory generalized MG.

METHODS

Retrospective chart review of 14 patients with refractory generalized MG treated for 12 months with maintenance TPE therapy. Outcome measures were myasthenia gravis composite (MGC) score, myasthenia gravis activities of daily living (MG-ADL), number of acute exacerbations, medication changes, and adverse events. Data were collected at 3 monthly intervals for 12 months before and after initiation of TPE therapy.

RESULTS

Clinically meaningful reductions in mean MG-ADL (>2 points) (mean MG-ADL score: 9.9 ± 0.5; 12-month pre-TPE to 5.2 ± 0.9; 12-month post-TPE) and MGC (>3 points) (mean MGC score: 25.2 ± 1.6; 12-month pre-TPE to 11.7 ± 1.4; 12-month post-TPE) were observed at 3 months following initiation of TPE and were maintained up to 12 months in all patients. After 12 months of TPE therapy, all patients had a significant reduction in daily prednisone and pyridostigmine use. Patients previously on IVIG or rituximab therapy were successfully weaned off both treatments. There was a significant reduction in acute MG exacerbations; 7.8 ± 1.1 mean exacerbations/patient (12-month pre-TPE) to 2 ± 1.1 mean exacerbations/patient (12-month post-TPE).

CONCLUSION

Over a period of 12 months, maintenance TPE therapy improved MG-ADL, and MGC with decreased immunosuppressant requirement, while being well-tolerated.