Two-year treatment with cyclosporine microemulsion for responder myasthenia gravis patients

Background: Cyclosporine (CsA) microemulsion pre-concentrate (MEPC) is a potential steroid-sparing agent for myasthenia gravis (MG) patients; however, there is a paucity of information on the long-term use of CsA MEPC in these patients. Objectives: We examined the efficacy and safety of CsA MEPC therapy administered to MG patients in a 2-year prospective open trial. Methods: From Hanamaki General Hospital and Keio University Hospital, 28 patients provided informed consent. They were enrolled in a prospective open study of CsA MEPC for the initial 6-month observation period; after this 9 were defined as poor responders and excluded from the long-term analysis. Results: The proportion of patients with minimal manifestations or pharmacologic remission status increased significantly. Among 18 patients taking oral prednisolone, 16 (88.9%) achieved a ≥50% reduction in prednisolone dose. Time to attain the minimal quantitative MG (QMG) score (4.2 ± 2.6) was 4.2 ± 4.2 months. Time to attain the minimal dose of prednisolone (2.9 ± 3.1 mg/day) was 9.3 ± 6.9 months. The dose of CsA MEPC was reduced to 2.6 mg/kg/day 2 years after starting the drug. Both total and ocular QMG scores were significantly decreased at 6 months and were generally maintained thereafter. The dose of prednisolone was significantly reduced at 1 year, and further reduced at 2 years. BMI decreased significantly, and 9 of 12 (75%) patients complaining of moon face reported that this had resolved on exit. All patients tolerated CsA MEPC without significant side effects. Conclusion: CsA MEPC therapy in responder MG patients suppressed disease severity, reduced steroid requirements, and alleviated steroid-related side effects. These findings should be confirmed by prospective controlled double-blind trials.