Efgartigimod improves non-AChR generalized Myasthenia Gravis: a real world experience

IntroductionThe neonatal Fc receptor (FcRn) inhibitor Efgartigimod (EFG) has been approved for treatment of generalized Myasthenia Gravis (gMG) with anti-AChR antibodies. Information on the effect of EFG in non-AChR MG is limited. We investigated the efficacy of EFG in non-AChR gMG along a clinical follow-up of 2 years.MethodsWe treated 13 patients with gMG without anti-AChR antibodies: 5 MuSK+, 2 LRP4 + and 6 triple-negative (confirmed by live CBA). EFG was administered according to the GENERATIVE protocol (consisting of a Fixed period of 2 treatment cycles of 4 infusions at weekly intervals, followed by a Flexible period during which EFG was given in case of initial worsening) starting from November 2021. Outcomes were evaluated by means of the MG-ADL, QMG, MGC and MGQoL15r scales.ResultsThe mean follow-up was 21 +/- 5.3 months. Meaningful improvement was observed with the clinical scores adopted. The number of cycles/year was 3.92 +/- 0.9. The interval between cycles was 10.1 +/- 3.6 weeks. MG-ADL improvement of at least 5 points was recorded in 58% of cycles. 46% of patients required hospitalization during the two years before treament with EFG and 70% plasmaexchange/IVIG; during EFG none of the patients was hospitalized or required immunomodulation. No major side effects or infusion related reactions occurred.ConclusionEFG was effective in non-AChR gMG and modified significantly the course of the disease. Our experience strengthens the role of FcRn inhibition as a new therapeutic tool for MG without anti-AChR antibodies.