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* Hui Chen and Yu Wu contributed equally as co-first authors.

Eculizumab is approved for refractory acetylcholine receptor antibody positive (AChR+) generalized myasthenia gravis (gMG). However, real-world evidence remains limited in addressing two critical scenarios: prolonged ventilator-dependent Myasthenia Gravis Foundation of America (MGFA) class V disease and thymoma-associated postoperative crises with multiple autoantibodies.

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Case 1:

A 47-year-old woman with a history of thymoma (treated with CyberKnife in 2019) and follicular thyroid carcinoma (status post thyroidectomy in 2021) presented in March 2024 with limb weakness and dyspnea; she was diagnosed with AChR+ gMG. She exhibited 12-month ventilator dependence and refractoriness to conventional therapies and efgartigimod.

Nevertheless, eculizumab enabled successful extubation within 10 days. Her Myasthenia Gravis–Activities of Daily Living (MG-ADL) score improved from 18 on admission to 0, reflecting functional recovery with independence in daily activities.

Case 2:

A 44-year-old woman presented in 2018 with right eyelid ptosis, mastication weakness, and limb weakness. She was diagnosed with AChR+, titin antibody positive (titin+), ryanodine receptor antibody positive (RyR+) gMG and thymoma. After initial medical management, she underwent resection of type B1 thymoma, with recurrence as type B2 in April 2021. In December 2024, PET-CT showed progressive pleural metastases, and thoracoscopic resection with left lower lobe wedge resection was performed in January 2025. She encountered postoperative crisis despite perioperative therapy with efgartigimod. Eculizumab improved symptoms by reducing MG-ADL scores from 12 to 4 in 10 days, with further improvement to 1 with maintenance therapy.

These cases demonstrate eculizumab's efficacy in liberating long-term ventilator-dependent gMG patients with MGFA class V from respiratory support, as well as resolving postoperative crises in thymoma-associated, multi-antibody positive refractory gMG. Both patients showed improvement in MG-ADL scores, reflecting significant recovery. These findings provide valuable real-world evidence to guide management for high-risk clinical presentations.