Myasthenia Gravis Crisis

This study plans to learn more about if the drug efgartigimod can be used in the hospital to treat exacerbations in participants with myasthenia gravis (MG). Efgartigimod has been approved by the FDA for ongoing (chronic) treatment of generalized MG in adult patients who are anti-acetylcholine receptor (AChR) antibody positive but has not been studied in the treatment of worsening weakness requiring hospital admission (known as "exacerbation"). This investigation aims to see if using efgartigimod in this way improves symptoms and recovery from exacerbation, and how it affects certain MG markers in the blood. The main questions it aims to answer are: * Is efgartigimod effective as a hospital-administered acute therapy for participants with worsening MG (MG exacerbation) who require hospitalization? * Will efgartigimod lead to clinical improvement with a similar reduction in validated research scales, such as the Quantitative MG (QMG) scale, as standard of care therapies? Participants will receive 4 doses of efgartigimod over the course of 4 weeks with an additional follow-up visit at the clinic.

Efgartigimod in Myasthenic Crisis Background Myasthenia gravis (MG) is a prevalent autoimmune disorder affecting neuromuscular junctions, characterized by weakness in skeletal muscles. It is associated with the production of autoantibodies, primarily targeting acetylcholine receptors (AchR), and is often complicated by myasthenic crisis, which can lead to severe respiratory failure. Current treatments primarily involve non-specific immunosuppression, which may not provide rapid relief. Aim This study investigates the therapeutic impact of efgartigimod, an FcRn-targeting Fc fragment, on patients experiencing a myasthenic crisis. We hypothesize that efgartigimod is non-inferior to conventional treatments like intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) in terms of clinical efficacy and safety. Study Rationale Efgartigimod aims to reduce pathogenic IgG autoantibodies implicated in MG by accelerating their degradation. This targeted approach could provide faster symptom relief during acute exacerbations compared to existing therapies. Objectives Primary Objective: To assess the non-inferiority of efgartigimod compared to PLEX and IVIG based on MG-ADL improvements. Secondary Objectives: Evaluate safety, tolerability, length of hospital stay, respiratory parameters, need for additional therapies, and one-year outcomes. Primary Endpoint MG-ADL Improvement: Defined as a ≥3-point improvement post-treatment. The comparison will be made using one-month post-treatment assessments, with follow-ups every three months. Secondary Endpoints Safety and tolerability Length of hospital stay Changes in respiratory function Need for rescue therapy in case of clinical deterioration Sample Size The study will recruit 32 patients (16 historical group and 16 interventional group), calculated to detect significant differences in MG-ADL improvements with a significance level of 0.05 and power of 0.80. Patient Recruitment Patients with a confirmed diagnosis of MG who present to the neurology department will be recruited and randomly assigned to either the efgartigimod treatment group or the historical control group receiving standard care (IVIG/PLEX). Inclusion Criteria Adults \> 18 years Confirmed MG diagnosis with generalized weakness (MGFA class II-V) Positive AchR or MuSK antibodies Evidence of myasthenic crisis Informed consent Exclusion Criteria Contraindications to efgartigimod Significant comorbidities affecting study participation Prior exposure to efgartigimod Ongoing infections or conditions exacerbating MG symptoms Recent major surgery or significant renal/hepatic dysfunction Planned Protocol Administer efgartigimod intravenously at 10 mg/kg weekly for four weeks. Total trial duration: 12 months for enrollment and treatment, followed by a 14-month follow-up.

The goal of this observational study is to learn about the experiences of people living with Myasthenia Gravis (MG) in the United States. The main questions it aims to answer are: * How and when are people with MG diagnosed? * What are the most common symptoms associated with MG? * What treatments are being used to treat MG? * What are the impacts of MG on activities of daily living, employment and quality of life? * What are the experiences with exacerbation, hospitalization and healthcare access for people with MG? Participants will answer a survey to enroll in the study, and be invited to fill out an update survey twice a year.

This study aims to characterize the clinical features, frequency of different subgroups of MG, and identify predictors of treatment responsiveness among different subgroups of MG. The predictors are including primary outcome (percentage of changes in MG scales at baseline at time of enrollment and after 3 months) and secondary outcome (treatment-related adverse events). Also it aims to determine the frequency of patients with refractory MG. This information will be used to understand the trends and mechanisms of disease relapse, and optimal management strategies.