Perioperative Safety and Efficacy of Efgartigimod for Thymoma associated Myasthenia Gravis: A Prospective, Multicenter, Phase II Clinical Trial.

Abstract

Introduction: This study reports the primary perioperative outcomes of efgartigimod in patients with thymoma-associated myasthenia gravis (TAMG).

Methods: We conducted a prospective, single-arm clinical trial to evaluate the perioperative use of efgartigimod in acetylcholine receptor antibody-positive (AChR-Ab+) generalized TAMG. Efgartigimod was administered intravenously at a dose of 10 mg/kg on Days 1, 8, 15, and 22, totaling four doses, with thymomectomy performed on Day 9.

Results: Forty patients with TAMG were enrolled, with a median age of 46 years. The predominant thymomectomy approach was T2b minimally invasive thymectomy, performed in 21 of 40 patients (52.5%). All patients were classified as responders on the Myasthenia Gravis Activities of Daily Living (MG-ADL), Quantitative Myasthenia Gravis (QMG), and Myasthenia Gravis Composite (MGC) scale, showing improvement across ocular, bulbar, limb, and respiratory muscle strength. At visit 4, myasthenic symptoms were obvious relieved, with reductions of 4.6 on MG-ADL compared to baseline. Significant reductions were noted in both serum IgG and AChR-Ab levels, without affecting other immunoglobulin classes or complements levels, following efgartigimod administration. The mean total postoperative hospitalization stay was 7.1 days. The total incidence of all-grade treatment-emergent adverse events (TEAEs) was 62.5% and the most TEAEs were reported to be mild. Postoperative myasthenic crisis occurred in 4 patients (10.0%) who underwent extended thymectomy.

Conclusion: The satisfactory outcomes and rapid neurological remission demonstrated efgartigimod had favorable safety and efficacy profiles during the perioperative period of thymomectomy for TAMG. These findings support the potential of efgartigimod as a novel perioperative treatment option for TAMG.