Intravenous Human IgG1 Fc Fragment (Efgartigimod) in Myasthenic Crisis

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 pre