Real-world implications of efgartigimod in managing refractory myasthenia gravis

Refractory myasthenia gravis (RMG) affects 10-20% of patients with generalized MG (gMG) and is associated with persistent disability, recurrent myasthenic crises, and elevated healthcare costs despite multiple lines of immunosuppressive therapy. Efgartigimod (EFG), an engineered IgG1 Fc fragment that competitively inhibits the neonatal Fc receptor (FcRn), reduces pathogenic IgG and is approved for gMG in more than 30 countries worldwide.

This review synthesizes evidence on EFG in RMG from a literature search of PubMed and Embase (inception to March 2026), covering international refractory definitions, the ADAPT trial, multicenter real-world cohorts, rescue therapy in myasthenic crisis, treatment switching after biologic failure, and safety.

EFG provides consistent symptom relief and substantial corticosteroid-sparing benefits across diverse RMG subtypes, including seronegative patients and those unresponsive to C5 complement inhibitors or B-cell depleting agents. EFG also serves as an effective rapid rescue therapy for refractory myasthenic crises. Despite reducing circulating IgG by approximately 60%, EFG does not increase severe infection rates. Therapeutic limitations include autoantibody rebound and inefficacy against non-IgG pathogenic autoantibodies. Further prospective trials utilizing modernized RMG definitions and validated predictive biomarkers are essential to establish EFG's therapeutic role in this challenging population.