Introduction Patients with systemic lupus erythematosus (SLE) have variable treatment pathways, including antimalarials, glucocorticoids, immunosuppressants, and/or biologics. This study describes differences in clinical outcomes when initiating belimumab (BEL) before and after immunosuppressant use.Methods This real-world, retrospective cohort study (GSK Study 217536) used de-identified administrative claims data from January 2015 to December 2022 in the Komodo Health Database. Adults with moderate/severe SLE initiating BEL (index date) were identified from January 2017 to May 2022, allowing a >= 24-month baseline period. Patients were stratified into those initiating BEL before immunosuppressant use (no immunosuppressant use within 24 months before index) and those initiating BEL after immunosuppressant use (one immunosuppressant used within 24 months before index). Oral glucocorticoid (OGC) use, SLE flares, new organ damage, and all-cause healthcare resource utilization (HCRU) were analyzed descriptively over a 24-month follow-up.Results Baseline SLE severity was similar for patients initiating BEL before (n = 2295) versus after (n = 4114) immunosuppressant use (moderate, 83.1% vs 79.0%; severe, 16.8% vs 21.0%). Patients initiating BEL before versus after immunosuppressant use had lower SLE flare rates and OGC use. Post-index, patients initiating BEL before versus after immunosuppressant use discontinued their OGC sooner (moderate baseline SLE, 4.5 vs 8.9 months; severe baseline SLE, 6.2 vs 11.6 months). Patients initiating BEL before versus after immunosuppressant use had lower SLE flare rates per person-year at all time points (especially severe flare rates in patients with severe baseline SLE, 0.70 vs 1.48 through 24 months post-index). Median time to new organ damage occurrence was longer in patients initiating BEL before versus after immunosuppressant use (moderate baseline SLE, 32.1 vs 26.7 months; severe baseline SLE, 22.7 vs 21.6 months). All-cause HCRU was similar between cohorts.Conclusions These results suggest that patients initiating BEL before versus after immunosuppressant use had more favorable outcomes.
