Assessing Efgartigimod Dosing Patterns and Myasthenia Gravis Activities of Daily Living Outcomes in Clinical Practice: Results From a Large Patient Support Program Database in the United States
Pushpa Narayanaswami1, Martina Orlovic2, Cynthia Qi2, Ratna Bhavaraju-Sanka3, A. Gordon Smith4, Matthew Jefferson2, Deborah Gelinas2, Rohit Menon5, Mai Sato5, Gil Wolfe6
1Beth Israel Deaconess Medical Center, 2argenx, 3UT Health Science Center @ San Antonio, 4Virginia Commonwealth University, 5ZS Associates, 6Univ. At Buffalo, SUNY
Objective:
Evaluate dosing patterns and Myasthenia Gravis Activities of Daily Living (MG-ADL) responses following efgartigimod initiation among patients with generalized myasthenia gravis (gMG) in the United States (US).
Background:
Efgartigimod is an engineered human Fc-fragment that is approved globally for treatment of anti-acetylcholinesterase receptor antibody positive (and regardless of antibody status in Japan) gMG. Each efgartigimod cycle consists of 1 infusion each week for 4 weeks; intervals between cycles vary based on individual response, enabling adaptability for heterogeneous phenotypes.
Design/Methods:
US adults (aged ≥18 years) with gMG who initiated efgartigimod by April 1, 2025, and enrolled in the My VYVGART Path patient support program were included. Efgartigimod infusion dates and MG-ADL scores were captured through phone contact. Patients with both baseline (pre-efgartigimod) and ≥4 MG-ADL scores captured post-efgartigimod initiation were included. To assess dosing patterns, weeks between treatment cycles were analyzed. To analyze outcomes, lowest MG-ADL scores post-efgartigimod initiation were compared with baseline scores for each patient, then averaged at the population level.
Results:
2648 patients were included; mean (SD) age was 67.5 (15) years and 1132 (43%) were female. Among all efgartigimod cycles, 4 weeks was the most common interval (28% of all identified intervals). At the population level, mean (SD) baseline MG-ADL score was 8.2 (3.7). Mean largest MG-ADL improvement from baseline after efgartigimod initiation was 5.8 points, with 91% of patients experiencing clinically meaningful improvement (CMI; 2-point improvement in MG-ADL). At any time after efgartigimod initiation, 83% (n=2185) achieved mild disease state of MG-ADL ≤4, and 45% (n=1188) achieved minimal symptom expression (MSE; MG-ADL of 0 or 1).
Conclusions:
Among patients who initiated efgartigimod in clinical practice, intervals between cycles were most commonly 4 weeks, with substantial proportion achieving CMI and almost half achieving MSE. Limitations include some potential selection bias with patients enrolled in the PSP.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.