“Introduction: We report real-world data on the use of Efgartigimod, a neonatal Fc-receptor antagonist, in AChR-positive generalized Myasthenia Gravis (gMG).

Methods: We reviewed the medical records of seven AChR+ gMG patients treated with Efgartigimod at IRCCS San Raffaele Scientific Institute from October 2022 to March 2024.

Results: Seven patients(male=3) with a mean age of 75.5(41-82) years were reviewed. Indications included: refractory gMG(n=1), insufficient control post-Azathioprine(n=2), immunosuppressive therapy(IST) contraindications(n=3), and refractory dysphagia despite rescue therapy(n=1). The median disease duration before Efgartigimod was 36(1-340) months. The median baseline Myasthenia Gravis Activities of Daily Living (MG-ADL) was 10.5(7-12), Quantitative Myasthenia Gravis(QMG) was 13(11-28) and Myasthenia Gravis Quality-of-Life-15(MG-QoL15) was 23(14-44); Myasthenia Gravis Foundation of America(MGFA) classification ranged from IIb to IVb. Patients underwent four-weekly cycles of treatment: one patient completed three cycles, three patients completed two cycles and two patients completed one cycle. One patient completed five cycles, after which treatment schedule was adjusted to biweekly administrations based on symptom progression. All patients showed clinical improvement during treatment. The proportion of MG-ADL responders(2-points reduction) and QMG(3-points reduction) responders after the first treatment cycle was 85%. The remaining 15%, partial responders, did not exhibit meaningful improvement after the following cycles administered at standard schedule. Three elderly patients reported respiratory adverse events, including one pneumococcal pneumonia that required hospitalization.

Discussion: These real-world longitudinal data show that Efgartigimod determines a rapid and significant clinical improvement in AChR+ gMG patients. However, safety in elderly patients should be carefully evaluated and optimal treatment frequency for symptom control needs to be further explored.”