Switching From Ravulizumab to Zilucoplan in Anti‐Acetylcholine Receptor Antibody–Positive Generalized Myasthenia Gravis: A Case Report

Background Ravulizumab (RAV) is a long‐acting complement C5 inhibitor used to treat anti‐acetylcholine receptor (AChR)‐positive generalized myasthenia gravis (gMG). However, fluctuations in symptoms have been observed in some patients during RAV therapy. Here, we describe a patient with anti‐AChR antibody–positive gMG who developed recurrent worsening symptoms during the latter phase of the RAV dosing interval, and subsequently achieved symptom stabilization after switching to zilucoplan (ZIL). Case Presentation A 58‐year‐old man with anti‐AChR antibody–positive gMG was treated with targeted immunotherapy and followed up longitudinally at our institution. He was diagnosed with gMG at 52 years of age and subsequently experienced repeated exacerbations and remissions. 6 years after disease onset, treatment with RAV was initiated, resulting in clinical improvement. However, after transitioning to the maintenance regimen, symptom recurrence consistently developed approximately 1 week before the next scheduled infusion. After switching to ZIL, these fluctuations resolved and his symptoms remained stable. Conclusions The clinical course of this patient suggests an association between RAV treatment and the periodic worsening of symptoms. In this patient, the symptoms stabilized after switching to ZIL in combination with ongoing immunotherapy.