Case Report: Dual response to efgartigimod in myasthenia gravis and comorbid autoimmune disorders: a case series

TL;DR

This case series shows that efgartigimod effectively treats myasthenia gravis and related autoimmune diseases by reducing IgG antibodies.

Contribution

Reports four cases showing efgartigimod's efficacy in treating MG with comorbid IgG-mediated autoimmune disorders.

Findings

Efgartigimod improved QMG and MG-ADL scores in patients with MG and overlapping autoimmune diseases.

Patients showed clinical or laboratory improvements in their comorbid IgG-mediated conditions.

The results suggest efgartigimod is a promising treatment for MG with IgG-related autoimmune complications.

Abstract

The coexistence of myasthenia gravis (MG) with other IgG-mediated autoimmune diseases represents a clinically heterogeneous condition, driven by pathogenic autoantibodies. Efgartigimod, a neonatal Fc receptor antagonist, has the ability to clear all IgG subclasses. Here, we report four cases of MG concomitant with IgG-mediated autoimmune diseases, specifically idiopathic inflammatory myopathies (IIM), Isaacs syndrome, autoimmune encephalitis (AE), and IgG4-related disease (IgG4-RD). All of them demonstrated a favorable therapeutic response to efgartigimod, with marked improvement in QMG and MG-ADL scores, along with disease-specific clinical or laboratory manifestations of the overlapping autoimmune conditions. These cases provide preliminary evidence supporting efgartigimod as a promising treatment option for patients with MG complicated by IgG-mediated autoimmune diseases.

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