Real-world evidence on utilization and clinical outcomes of efgartigimod in patients with generalized myasthenia gravis.

Conventional therapies for acetylcholine receptor antibody-positive (AChR-Ab+) generalized Myasthenia Gravis (gMG) often provide inadequate disease control. Although neonatal Fc receptor (FcRn) inhibitors have proven effective in clinical trials, real-world evidence on their use and effectiveness in heterogeneous patient populations is still limited. This study evaluates clinical outcomes, steroid-sparing effects, and treatment utilization of efgartigimod in patients with refractory AChR-Ab+ gMG. We conducted a retrospective analysis of 27 adult patients with AChR-Ab+ gMG treated with efgartigimod. Effectiveness, treatment utilization and long-term outcomes were evaluated over seven treatment cycles using longitudinal Myasthenia Gravis Activities of Daily Living (MG-ADL) scores, inter-cycle interval duration, daily corticosteroid dosing, need for rescue therapies, and transition to other advanced therapies. In total, 130 treatment cycles were analyzed. Overall, the patients showed rapid and sustained clinical improvement. Baseline MG-ADL scores (EMM = 8.48) significantly decreased by 2.96 points by cycle-2 (p < 0.001), reaching maximum reduction of 3.95 points by cycle-6. Severe impairment (MG-ADL ≥ 10) decreased from 41% at baseline to 0% by cycle-5, while 66% of patients achieved mild symptoms (MG-ADL 2-4) or Minimal Symptom Expression by cycle-7. Significant corticosteroid-sparing effect occurred by cycle-3 (p = 0.023), with mean daily methylprednisolone doses decreasing from 5.8 mg at baseline to 2.3 mg by cycle-5. Four patients (15%) were non-responders and transitioned to complement inhibition therapy. Real-world efgartigimod use provides rapid symptomatic relief and significant corticosteroid reduction in patients with refractory AChR-Ab+ gMG. While most achieve sustained improvement, non-responders and patients with history of myasthenic crises require close monitoring and potential transition to alternative advanced therapies.