Chronic low-dose intravenous immunoglobulins as steroid-sparing therapy in myasthenia gravis.

INTRODUCTION: Intravenous immunoglobulin (IVIg) has been proven beneficial in myasthenic crisis, but their role as maintenance therapy is unclear. The aim of this study was to determine if maintenance therapy with low-dose IVIg improves clinical outcome and may be used as a steroid-sparing agent in myasthenia gravis (MG).

METHODS: We retrospectively reviewed charts of all MG patients treated with IVIg from January 2006 to December 2019. Long-term treatment response to IVIg was assessed by improvement in the Myasthenia Gravis Foundation of America (MGFA) clinical classification scale as primary end point, as well as the ability to reduce the time-weighted average required dose of prednisone as secondary end-point, in a follow-up period of 36 months.

RESULTS: 109 patients were treated with IVIg. The mean follow-up time was 34.03 ± 5.5 months. Sixty-seven patients (61.4%) responded to therapy with at least one-point improvement of the MGFA scale. There was no statistical difference in demographic and clinical characteristics between IVIg responders and non-responders. The mean prednisone dose decreased significantly from 33.1 ± 14.5 mg at baseline to 7.2 ± 7.8 mg after 36 months of IVIg treatment (P < 0.0001), with the greatest effect after 6 months (33.1 ± 14.5 mg Vs. 17.9 ± 11.7 mg; P < 0.0001). In the follow-up period of 36 months, most patients (92.5%) remained clinically and pharmacologically stable under chronic IVIg treatment.

CONCLUSION: This retrospective study demonstrates that chronic low-dose IVIg treatment in patients with MG improves clinical outcomes and has a prolonged and significant steroid-sparing effect over a period of 3 years.