Efgartigimod as Rescue Treatment in Acute Phase of Neuromyelitis Optica Spectrum Disorder: A Case Report

Introduction Neuromyelitis optica spectrum disorder (NMOSD) is a central nervous system demyelinating disease. Current therapy methods, however, have limited effect on acute NMOSD attacks except for intravenous methylprednisolone (IVMP). Efgartigimod is a first-in-class novel human immunoglobulin G1 (IgG1) Fc fragment approved for the treatment of generalized myasthenia gravis. Its capacity to rapidly decrease serum IgG levels, including pathogenic autoantibodies, positions it as a potentially effective option for managing the acute phase of NMOSD. Case Presentation We report the case of a 59-year-old female patient with acute NMOSD, presenting with vision loss and numbness in all four limbs. Despite an initial inadequate response to intravenous methylprednisolone (IVMP), the addition of Efgartigimod to her treatment regimen led to rapid improvement, notably including a significant reduction in serum aquaporin-4 antibody titers, total IgG levels, and inflammation related cytokine levels. Furthermore, no adverse events were reported during a four-month follow-up period. Conclusion As an adjunct to glucocorticoid therapy, Efgartigimod has proven effective and safe for this patient. However, to ascertain its potential as a novel therapeutic option for acute NMOSD, larger-scale prospective clinical trials are required.