Long-term steroid-sparing effect of belimumab in systemic lupus erythematosus: Post hoc pooled analysis of OBSErve multi-country cohort data

ObjectiveBelimumab, a B-cell modulator, targets the central immunopathogenic pathway in systemic lupus erythematosus (SLE) by selectively inhibiting B lymphocyte stimulator (BLyS) and reducing the autoreactive B cells that drive disease activity. Its effectiveness in reducing disease activity and its steroid-sparing potential have been well-documented in both clinical trials and real-world studies. This study evaluated belimumab's long-term effectiveness in reducing oral glucocorticoid (OGC) use based on updated European Alliance of Associations for Rheumatology (EULAR) recommendations, and in attaining low disease activity and remission in adults with SLE.MethodsThis post hoc descriptive analysis (GSK Study 219649) utilized pooled data from individual OBSErve studies conducted in eight countries, collected at belimumab initiation and 6 months (all countries), and 6 to 24 months (USA and Argentina) post-initiation. Endpoints included percentages of patients achieving ≤5 mg/day OGC; maintaining 0 and ≤5 mg/day OGC beyond 6 months; attaining low disease activity (modified Lupus Low Disease Activity State [mLLDAS]: SLE Disease Activity Index [SLEDAI] score ≤4, OGC dose ≤7.5 mg/day) and remission (modified Definition Of Remission In SLE [mDORIS]: SLEDAI score = 0, OGC dose ≤5 mg/day) over time. The sample size in this study was fixed by available data from the OBSErve studies.ResultsData from 959 patients were included (mean [SD] age: 41.5 [12.4] years; 89.5% female; 52.2% from the USA). Of patients prescribed OGC at index, percentages receiving ≤5 mg/day increased from 16.1% at belimumab initiation to 51.6% at 6 months and 87.5% at 24 months; 8.2% discontinued OGC at 6 months and 44.4% at 24 months post-initiation. Of patients achieving 0 and ≤5 mg/day OGC at 6 months, 87.9% and 92.9% maintained this dose for 24 months. Percentage attaining mLLDAS/mDORIS increased from 0.4%/0.2% at belimumab initiation to 11.1%/7.4% at 6 months and 18.2%/12.9% at 24 months post-initiation.ConclusionsThese results from a real-world clinical setting suggest that belimumab treatment supports patients in achieving EULAR-recommended OGC taper goals, with sustained OGC dose reductions observed alongside an increased percentage of patients attaining low disease activity and remission as early as 6 months following belimumab initiation.