Case Report: Efgartigimod demonstrates significant clinical efficacy in double seropositive myasthenia gravis: a case report of a rare variant and analysis of pathomechanisms

TL;DR

A 68-year-old woman with a rare form of myasthenia gravis showed significant improvement after treatment with efgartigimod, a promising new therapy for this condition.

Contribution

This is the first documented case of efgartigimod's efficacy in treating double seropositive myasthenia gravis.

Findings

The patient showed complete resolution of symptoms after efgartigimod treatment.

Sustained clinical remission was maintained for 6 months post-treatment.

Efgartigimod may offer a viable treatment option when conventional therapies fail.

Abstract

Double Seropositive Myasthenia Gravis (DSP-MG), a rare variant of Myasthenia Gravis (MG), is defined by the simultaneous presence of both anti-acetylcholine receptor (AChR) antibodies and anti-muscle-specific tyrosine kinase (MuSK) antibodies in the serum of affected individuals. Currently, no standardized therapeutic protocol exists for DSP-MG due to its scarcity and clinical heterogeneity. Herein, we report a case of a 68-year-old female patient with DSP-MG who showed significant clinical improvement during an acute exacerbation after treatment with the FcRn antagonist efgartigimod, following the failure of conventional therapy. After a cycle of efgartigimod treatment, complete resolution of myasthenic symptoms was observed. During the 6-month follow-up, with sustained clinical remission and attainment of Minimal Manifestation Status (MMS). This case represents the first documented use of efgartigimod in a DSP-MG patient, providing preliminary clinical evidence for its potential efficacy in this rare and poorly understood subtype. Our findings contribute to the limited literature on DSP-MG and suggest that FcRn inhibition may offer a viable treatment option where conventional therapies fail. Efgartigimod may represent a potential therapeutic agent for DSP-MG.

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