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

A systematic review of efgartigimod as an effective treatment for myasthenic crisis

Efgartigimod is a neonatal Fc receptor (FcRn) inhibitor that primarily diminishes antibody levels by inhibiting antibody (IgG) reabsorption and is noted for its rapid onset of action and low immunogenicity. Currently, efgartigimod is approved for the treatment of anti-acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG), yet there are no relevant clinical trials for myasthenic crisis (MC). Consequently, we performed a systematic review of the available literature to evaluate the clinical efficacy of efgartigimod for the treatment of MC. We conducted a search of the PubMed, Web of science, Embase, and Scopus databases for all observational studies published until September 30, 2024. Risk of bias was assessed using the Joanna Briggs Institute (JBI) Case Report and Series Critical Assessment Checklist for quality assessment of included studies. A total of nine case reports/series, all observational studies, were included. Twenty MC patients were included, all of whom exhibited clinically significant improvement after treatment with Efgartigimod, with a sustained decrease in AChR antibody serum titers and a significant decrease in IgG levels throughout the treatment cycle. Efgartigimod demonstrates favorable clinical efficacy. Efgartigimod may serve as an effective treatment for patients with MC. However, further studies are required to clarify the efficacy of Efgartigimod alone. PROSPERO registration number: CRD42023430032.

First line treatment with subcutaneous efgartigimod in impending myasthenic crisis: a case report

In acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG), neonatal Fc-receptor (FcRn) inhibition has broadened the therapeutic spectrum. Myasthenic crisis (MC), heralded by an impending myasthenic crisis (iMC), is a critical condition requiring treatments with rapid onset and sustained efficacy. Currently treatments used for iMC, including intravenous immunoglobulins and plasma exchange/immunoadsorption, have limitations, such as delayed onset of action and potential side effects. So far, there is limited data on the use of FcRn inhibitors in the management of impending or manifest MC (mMC). Here, we present a case of AChR antibody-positive gMG with iMC, where subcutaneous administration of the FcRn inhibitor efgartigimod resulted in rapid clinical remission. Within 24 h of administration, the patient exhibited significant improvement in respiratory and bulbar muscle function, preventing progression to manifest MC and the need for mechanical ventilation. This rapid response was accompanied by a marked reduction in AChR antibody level by 89.8% within 4 weeks. This case supports the potential of efgartigimod as a fast-acting and effective treatment option for managing iMC, offering an alternative to existing therapies.

Efgartigimod as a fast-acting add-on therapy in manifest and impending myasthenic crisis: A single-center case series

Efgartigimod was the first-in-class neonatal Fc receptor antagonist approved for the treatment of acetylcholine receptor antibody positive (AChR+), Myasthenia Gravis Foundation of America (MGFA) Class II-IV generalized myasthenia gravis (gMG) patients. As a novel therapy, the clinical experiences are still lacking, especially for the use of efgartigimod in manifest and impending myasthenic crisis (IMC). We reported three AChR+, gMG patients, two with myasthenic crisis (MC) and one with IMC, treated with efgartigimod. MGFA class, MG-Activity of Daily Living score (MG-ADL), Quantitative MG score (QMG), and Muscle Research Council sum score (MRC), concentration of anti-AChR antibody, IgG, globulin, and albumin, subsets of T and B lymphocyte were evaluated or measured before, during and after efgartigimod treatment. All patients showed fast and robust response to efgartigimod with marked improvement in MGFA, MG-ADL, QMG, and MRC scores. Patient 1 did not respond effectively to IVIg but was successfully rescued by add-on efgartigimod. She extubated at 7 days after the first infusion and got rid of NIV after 14-days treatment. Patient 2 and patient 3 directly used efgartigimod when symptoms were not ameliorated by adjusting of oral drugs. Patient 2 wean from BiPAP at seven days after the first infusion. Patient 3 in IMC status, overcame the severe dysphagia at three days after the first infusion. Clinical symptoms continued to improve 1-2 weeks after discharge. Concentration of anti-AChR antibody, IgG and globulin were remarkably reduced by efgartigimod treatment. Our study supported that efgartigimod could act as a fast-acting rescue therapy for patients with MC or IMC. Larger studies from multicenter are required to provide further evidence.

Comparative Analysis of Intravenous Immunoglobulins (IVIg) vs Plasmapheresis (PLEX) in the Management of Myasthenic Crisis

Myasthenia gravis (MG) is an autoimmune disorder affecting postsynaptic membranes in neuromuscular junctions, presenting as fatigable muscle weakness. Myasthenic crisis is a life-threatening complication characterized by severe respiratory insufficiency necessitating invasive or noninvasive ventilation. Two rapid therapies used to manage myasthenic crises are intravenous immunoglobulins (IVIg) and plasmapheresis (PLEX). Their comparative effectiveness remains equivocal. Our article examines evidence from several clinical trials and observational studies, in order to determine the superiority of one treatment over the other. Multiple factors can complicate the choices between two treatments. We concluded that the choice between PLEX and IVIg is multifaceted, guided by individual patient characteristics, institutional resources, and clinician preference. While PLEX can be considered as first-line for rapid clinical outcomes, it is hard to pick one treatment over the other, and careful consideration of comorbidities and resource availability is crucial. Our article highlights the need for further research to establish definitive guidelines and enhance patient outcomes in myasthenic crisis patients.

Plasma Exchange in Anti-Signal Recognition Particle Myopathy: A Systematic Review and Combined Analysis of Patient Individual Data

Anti-signal recognition particle myopathy (anti-SRP myopathy) is a rare subtype of immune-mediated inflammatory myopathy characterized by muscle weakness and anti-SRP autoantibodies. Although plasma exchange (PE) is used in severe cases, its role remains unclear. A systematic review was conducted following PRISMA guidelines, identifying 23 patients with anti-SRP myopathy treated with PE. Data on demographics, clinical features, laboratory findings, treatments, and outcomes were analyzed combining individual patient data if available. Sixteen (69.6%) patients were male, with muscle weakness as the predominant symptom in 100% of cases. After PE, most patients showed improvement in symptoms, and the proportion of patients with muscle weakness was reduced (p = 0.001). Relapse occurred in 17.4% of the cases. The incidence of adverse events was low (8.7%). Despite limitations, including a small sample size and heterogeneous data, our systematic review suggests that PE may be effective in inducing remission and controlling symptoms in anti-SRP myopathy, particularly in severe cases. Since evidence on PE in anti-SRP myopathy is limited, further research, including prospective multicenter studies, is warranted to understand better its efficacy and safety and establish its role in treatment algorithms.

Case report: Recovery from refractory myasthenic crisis to minimal symptom expression after add-on treatment with efgartigimod

Myasthenic crisis, a life-threatening exacerbation of myasthenia gravis, is a significant clinical challenge, particularly when refractory to standard therapies. Here, we described a case of myasthenic crisis in which the patient transitioned from refractory myasthenic crisis to minimal symptom expression after receiving add-on treatment with efgartigimod, a novel neonatal Fc receptor antagonist. A 54 years-old woman who was diagnosed with anti-acetylcholine receptor antibody-positive myasthenia gravis experienced respiratory failure necessitating mechanical ventilation. Despite aggressive treatment with plasmapheresis, intravenous immunoglobulins, and high-dose corticosteroids, her condition continued to deteriorate, culminating in persistent myasthenic crisis. Efgartigimod was administered as salvage therapy. Remarkable improvement in neuromuscular function was observed within days, allowing for successful weaning from mechanical ventilation. Over the subsequent weeks, the patient's symptoms continued to ameliorate, ultimately reaching a state of minimal symptom expression. Serial assessments of her serum anti-acetylcholine receptor antibody titer showed a consistent decline in parallel with this clinical improvement. This case highlights efgartigimod's potential as an effective therapeutic option for refractory myasthenic crisis, offering new hope for patients facing this life-threatening condition.