Introduction: Corticosteroids are ubiquitous in the treatment of generalized myasthenia gravis (gMG) despite evidence of adverse effects of long-term corticosteroid use.
Objectives: To evaluate (1) long-term corticosteroid use patterns in adult patients with gMG and (2) corticosteroid dose changes after initiating approved biologic treatments for gMG.
Methods: A retrospective cohort study was conducted using the Definitive Healthcare Atlas claims database. Patients with gMG were identified in US commercial claims data from January 2016 to September 2023. For Objective 1, descriptive statistics and longitudinal figures were used to describe and illustrate corticosteroid utilization over 24 months of follow-up since first gMG claim. For Objective 2, a multivariable regression model was used to estimate changes in corticosteroid dose pre- and post-initiation of C5 inhibitor therapies (C5iTs; eculizumab, ravulizumab) or a neonatal Fc receptor antagonist (FcRn-a; efgartigimod alfa).
Results: Overall, 2237 patients with gMG met inclusion criteria and were allocated to three treatment cohorts: no biologic (n=2006), C5iT (n=125) and FcRn-a (n=106). Steroid dose journey varied widely, but 454 patients (22.6%) started at doses >10 mg and, of those, 194 (42.7%) remained at doses >10 mg at 24 months. In the multivariable analysis, patients had an average reduction in annualized total corticosteroid use of 1562 mg (–36%; p=0.017) following initiation of C5iT and 668 mg (–21%; p=0.08) following initiation of FcRn-a therapy.
Conclusion: Steroid use patterns vary widely in adult patients with gMG, but persistent high-dose corticosteroid use is common, despite adverse effects. This study demonstrated that C5iTs facilitated significant steroid sparing within the first year of their initiation.