Real-World Utilization Patterns of Intravenous Immunoglobulin in Adults With Generalized Myasthenia Gravis in the United States

Abstract

Objective To evaluate real-world utilization patterns of intravenous immunoglobulin (IVIg) among patients with generalized myasthenia gravis (gMG) over 3 years post-IVIg initiation. Background gMG is a rare autoimmune neuromuscular disorder with no known cure. Although IVIg is the most commonly used add-on therapy after standard of care treatments in gMG, it is currently unclear whether it is more commonly used as a “one-off” treatment to manage exacerbations, or as maintenance therapy aimed at reducing or replacing steroid use. Design/Methods Patients with gMG who initiated IVIg treatment were identified from a US claims database (Symphony Health, an ICON plc Company, Integrated Dataverse [IDV]®, January 1, 2014-December 31, 2019). The frequency of subsequent IVIg treatment and associated cost during the first 12 months post-IVIg initiation were analyzed. Usage patterns of concomitant gMG treatments during the year preceding and 3 years post-IVIg initiation were compared. Results Among 1225 patients with gMG who initiated IVIg treatment, 706 patients (57.6%) received 1 to 5 IVIg treatment courses (intermittent IVIg users), and 519 patients (42.4%) received = 6 IVIg treatment courses (chronic IVIg users) within the subsequent year. Mean annual medical cost per patient was nearly 2.5-fold higher for chronic vs intermittent IVIg users ($161,478 vs $64,888, p < 0.001). Usage frequency of other immunotherapy treatments did not decrease over the follow-up period, even for patients who continued annual chronic IVIg for 3 consecutive years post-initiation. Conclusions Nearly half of patients with gMG received chronic and multiple IVIg treatment courses within the first year once initiating IVIg treatment, indicating higher usage than expected. For all IVIg initiators, usage frequency of other immunotherapy treatments did not decrease over 3 years despite IVIg initiation.