Myasthenia gravis (MG) is a neuromuscular disorder characterized by fluctuating muscle weakness. Approved biologic options for generalized MG include complement inhibitors (e.g., ravulizumab ) and FcRn antagonists (e.g., efgartigimod, rozanolixizumab), while B-cell-targeted agents (e.g., rituximab) are used off-label. While safety of these approved agents has been characterized in clinical trials, additional real-world evidence is needed to evaluate longer-term infection risks. The objective of this study is to estimate and compare the real-world infection rates associated with gMG treatments.
This study was a retrospective longitudinal cohort study of patients with MG using the Veeva Compass claims database from January 2017 to August 2025. Patients with MG initiating ravulizumab, efgartigimod, rozanolixizumab, or rituximab were identified, with index date as first treatment initiation. Infections were identified by diagnosis code, excluding duplicates using date of service, pathogen, and affected organ system. Baseline characteristics and crude infection rates were summarized by treatment. Negative-binomial generalized estimating equations was used to compare annual infection rates across cohort, with adjustment for known and suspected confounders , including concomitant corticosteroids, non-steroidal immunosuppressive therapies, and Charlson Comorbidity Index.
Of 1,515 patients, 689 (46.1%) initiated rituximab, 555 (36.6%) efgartigimod, 218 (14.4%) ravulizumab, and 53 (3.5%) rozanolixizumab. After confounder adjustment, both efgartigimod and rituximab showed statistically significantly higher infection rates versus ravulizumab – efgartigimod by 47% (IRR=1.47, 95% CI: 1.17–1.84, p<0.001) and rituximab by 46% (IRR=1.46, 95% CI: 1.23–1.72, p<0.001). Rozanolixizumab suggested a similar trend but was underpowered to detect differences due to small sample size (IRR=1.34, 95% CI: 0.85–2.11, p=0.208).
This study observed lower infection rates in patients receiving ravulizumab compared to those receiving other biologic therapies for gMG. Understanding real-world, long-term infection risk profiles for these drugs could help inform treatment decisions for MG, particularly for patients at higher risk of infection or infection-related complications.