Rapid efficacy of efgartigimod for generalized myasthenia gravis patients in acute exacerbations/worsening: multicenter real-world retrospective study

BACKGROUND AND OBJECTIVES: Acute exacerbations/worsening of generalized myasthenia gravis (gMG) require urgent intervention to prevent progression to life-threatening myasthenic crisis. This multicenter study evaluate the efficacy and safety of efgartigimod in gMG patients experiencing acute exacerbations/worsening to validate its potential as a rapid-acting therapeutic option. METHODS: In this multicenter retrospective study (Jan 2024-Feb 2025), 61 gMG patients with acute exacerbations/worsening received weekly efgartigimod infusions for 4 weeks. Efficacy was assessed at baseline (W0) and weekly throughout the treatment cycle (W1-W7) using Myasthenia Gravis Foundation of America Post-Intervention Status (MGFA-PIS), Quantitative Myasthenia Gravis (QMG), and Myasthenia Gravis Activities of Daily Living (MG-ADL) scores, along with prednisone dosage reductions. Safety assessments were concurrently performed. RESULTS: Median age was 56 years (range: 39-68 years). Pulmonary infection (16/61, 26.2%) was the predominant trigger of myasthenic crisis (MC) red flgs. Median duration from symptom deterioration to efgartigimod initiation was 18 days. Clinical meaningful improvement occurred in 81.9% at W1 (post-single dose), 98.1% at W4, and 91.9% at W7. MG-ADL and QMG scores decreased substantially from baseline (W4: 80.86% and 55.81% reduction; W7: 70.78% and 47.76% reduction), Patients with MC red flags achieved comparable outcomes. Greater MG-ADL imrovements were observed in those with thymoma history, severe MGFA classification, prior MC, or MC red flags. No treatment-related allergic reactions, infections, or serious adverse events were observed. CONCLUSION: Efgartigimod demonstrates rapid, significant efficacy in gMG acute exacerbations/worsening, supporting its role as a valuable therapeutic option for this high-risk population.