Assessing efgartigimod dosing patterns and Myasthenia Gravis Activities of Daily Living outcomes in clinical practice: results from a large patient support program database

Background: Efgartigimod, a neonatal Fc receptor (FcRn) blocker, is approved for the treatment of generalized myasthenia gravis (gMG). Evidence describing large-scale cohorts in routine United States (US) practice remains limited. Objective: To characterize efgartigimod dosing patterns and Myasthenia Gravis Activities of Daily Living (MG-ADL) outcomes among a US cohort enrolled in the My VYVGART Path patient support program. Methods: This retrospective cohort study analyzed adults with gMG who initiated efgartigimod on or before December 31, 2025, and had a baseline (pre-efgartigimod) MG-ADL score recorded and ≥4 follow-up assessments available. Outcomes included dosing interval distributions, longitudinal MG-ADL trends, durability of clinically meaningful improvement (CMI; ≥2-point reduction), and best observed response. Results: Among 3,326 eligible patients (mean [SD] baseline MG-ADL: 8.2 [3.8]; mean [SD] treatment duration: 18.0 [11.0] months), the most common inter-cycle interval length was 4 weeks, though intervals ranged widely, reflecting individualized care. Patients achieved rapid and sustained clinical improvement, with mean MG-ADL improvement of 3.3 points by Month 1 and 4.5 points by Month 18. Of 2,964 patients achieving CMI, the majority (>75%) maintained CMI for >80% of their available follow-up time. Best observed response analyses showed a mean (SD) improvement from baseline of 5.9 (3.5) points, with 83% achieving MG-ADL score ≤4 and 47% achieving minimal symptom expression (MG-ADL score 0-1). Conclusion: In this large and diverse US cohort, efgartigimod was administered using both proactive (structured) and individualized (flexible) dosing strategies, leading to rapid, deep, and sustained clinically meaningful improvements. These findings support efgartigimod as an effective and adaptable therapy for gMG in routine clinical practice.