To evaluate long-term clinical outcomes, treatment patterns, and predictors of efficacy of efgartigimod in acetylcholine receptor antibody–positive generalize myasthenia gravis (gMG).

Efgartigimod, a neonatal Fc receptor antagonist, lowers pathogenic IgG and has shown efficacy in gMG. Real-world data on long-term outcomes, steroid-sparing, bridging strategies, and predictors of response remain limited. 

This multicenter retrospective study included 46 adult patients treated across 7 tertiary centers between April 2022 and March 2025. Data on demographics, clinical features, treatments, and outcomes were collected. The primary endpoints were improvement in MG-ADL scores and achievement of minimal symptom expression (MSE). Secondary endpoints included corticosteroid dose reduction, successful use of efgartigimod as short-term bridging therapy for disease stabilization, and safety outcomes.

The patients received 197 cycles (mean 4.3 per patient) at a mean interval of 9.8 weeks. 40 (86.9%) patients achieved a ≥2-point improvement in MG-ADL and 20 (43.5%) patients reached MSE after the first cycle, while 24 (52.2%) achieved MSE at any point. Overall 36 (78.3%) patients maintained a ≥2-point improvement in MG-ADL, with response patterns ranging from cyclical benefit to sustained remission, although 14 (35.9%) patients discontinued treatment due to insufficient efficacy. The prednisone dose was reduced in 17 of the 29 (58.6%) treated patients (from a mean of 30.9 to 16.8 mg/day, p=0.001), with a shorter disease duration independently predicting success. Bridging therapy was successful in a subset of 5 patients, particularly among the those receiving azathioprine or mycophenolate (OR=15.0, p=0.040). Adverse events were mild and occurred in 10 (21.7%) patients, only 1 of whom discontinued therapy.