Safety and Effectiveness of Eculizumab in Patients With Refractory Ocular or Ocular‐Predominant Myasthenia Gravis: A Case Series

INTRODUCTION/AIMS: Despite conventional immunosuppressive therapy, approximately 5% of generalized myasthenia gravis (MG) patients experience residual ocular symptoms. We investigated the therapeutic effect of eculizumab, a C5 complement inhibitor, in five patients with refractory ocular myasthenia gravis (OMG) or ocular-predominant MG. METHODS: Five patients with acetylcholine receptor antibody-positive (AChR-Ab) refractory ocular or ocular-predominant MG received eculizumab therapy (induction: 900 mg weekly ×4 weeks; maintenance: 1200 mg biweekly) with baseline immunosuppression. Each patient was followed up for 12 weeks. Clinical assessments included ocular Quantitative Myasthenia Gravis (ocular-QMG), Myasthenia Gravis Composite (MGC), and MG activities of daily living (MG-ADL). Serum AChR-Ab titers were measured before and after treatment. RESULTS: All patients experienced rapid symptom improvement within 1 week. After 4 weeks, ocular function normalized in three patients, with four patients achieving MGC ≤ 2 and MG-ADL ≤ 2. The ocular-QMG scores for individual items showed that both ptosis and diplopia improved in most patients. At 12 weeks, four patients maintained stable symptom control. No treatment-related adverse events or significant AChR-Ab+ titer changes were observed. DISCUSSION: In patients with refractory ocular or ocular-predominant MG, eculizumab had a rapid onset of therapeutic effect that was sustained after 12 weeks, regardless of the antibody titer. The favorable safety profile supports its use in treatment-resistant cases of refractory OMG or ocular-predominant MG. Larger randomized controlled trials are needed to establish the long-term effectiveness and optimize treatment protocols.