Efficacy of efgartigimod in the treatment of autoimmune encephalitis: a systematic review.

BACKGROUND: Autoimmune encephalitis (AE) encompasses a group of inflammatory disorders of the brain parenchyma mediated by autoimmune mechanisms. Currently, first-line immunotherapy for AE typically involves corticosteroids, intravenous immunoglobulin, and plasma exchange or immune adsorption. However, a subset of patients shows an inadequate response to these treatments, which are also associated with an increased risk of infection and other potential adverse effects. Efgartigimod, a neonatal Fc receptor (FcRn) antagonist, is primarily approved for treating generalized myasthenia gravis. Preliminary observations suggest that efgartigimod may also exhibit therapeutic potential in AE. METHODS: A comprehensive literature search was performed in the PubMed, Web of Science, Embase, and Cochrane Library databases to identify all relevant studies published up to October 30, 2025. The risk of bias in the included studies was evaluated using standardized tools tailored to each study design. Owing to substantial heterogeneity across study designs and outcome measures, a meta-analysis was not deemed feasible; consequently, the findings are synthesized and presented in narrative form. RESULTS: Twelve studies were included, comprising nine case reports or series, two case control studies, and one cross‑sectional study. A total of 77 patients with AE were enrolled. The majority (76/77) demonstrated significant clinical improvement following efgartigimod treatment, and no serious adverse events were observed. CONCLUSION: Efgartigimod holds potential as a safe and effective adjunctive therapy for AE patients, either as adjunctive treatment after inadequate responses to first-line or second-line therapies or as concomitant add-on therapy combined with first-line treatment.