Single institution experience with efgartigimod in patients with myasthenia gravis: Patient selection, dosing schedules, treatment response, and adverse events

Abstract

Introduction/aims: Efgartigimod is a neonatal Fc receptor blocker and was the first approved medication in its class for the treatment of generalized myasthenia gravis (gMG). As a novel therapy, little is known about the use of efgartigimod in clinical practice. This study aims to describe how efgartigimod is being incorporated into the current therapeutic landscape of MG.

Methods: We reviewed the charts of 17 patients with gMG treated with efgartigimod at the University of Pennsylvania between January 2022 and June 2023.

Results: Efgartigimod was selected mainly for patients who were treatment refractory, had side effects to other treatments, and/or required quick improvement in their symptoms. All patients had been previously treated with at least one medication for MG and had an average baseline Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 9.1. The patients treated with efgartigimod improved their MG-ADL score by an average of 5.5 points at 3 months (p < .001) and 7.1 points by 6 months (p < .001). Forty percent of patients achieved minimal symptom expression. Adverse events (AEs) were reported in 43.7% of patients on efgartigimod, the most common being mild infection (urinary tract infection and thrush). There were no serious AEs.

Discussion: This study found efgartigimod to be efficacious, well tolerated, and safe in patients with MG. Efgartigimod should be considered as an add-on therapy, a bridge therapy, or as a monotherapy if patients have difficulty tolerating other treatments.

Keywords: AChR positive; FcRn inhibitor; MG-ADL; efgartigimod; myasthenia gravis.