THE EFFECT OF BELIMUMAB ON SRI-4 RESPONSE IN MULTIPLE SUBGROUPS OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: RESULTS OF A LARGE INTEGRATED ANALYSIS

BackgroundBelimumab (BEL) is approved for the treatment of active autoantibody-positive systemic lupus erythematosus (SLE).1 Four Phase 3 studies have consistently demonstrated greater SLE Responder Index (SRI) response rates with BEL vs placebo (PBO).2-5 This robust dataset allows for additional exploration of the onset of efficacy of BEL and response rates by patient (pt) characteristics.ObjectivesTo perform a post hoc analysis evaluating the effect of BEL on SRI-4 response across a large, pooled population and pt subgroups.MethodsThe Belimumab Summary of Lupus Efficacy (Be-SLE) integrated analysis evaluated data from adults with SLE from 5 double-blind, PBO-controlled BEL trials: BLISS-76, BLISS-52, BLISS-NEA, BLISS-SC, and EMBRACE.2-6 Pts were randomised to BEL (monthly intravenous 10 mg/kg or weekly subcutaneous 200 mg) or PBO, plus standard therapy. Data were collected every 4 weeks (wks) from baseline (BL) to Wk 52. The SRI-4 response rate (a composite measure that includes ≥4-point reduction in Safety of Estrogens in Lupus Erythematosus National Assessment - SLE Disease Activity Index [SELENA-SLEDAI] score, stable Physician Global Assessment [PGA] increase of <0.3, and no new British Isles Lupus Assessment Group [BILAG] 1A/2B organ domain scores) by visit and time to first SRI-4 response maintained through Wk 52 were determined for both treatment groups. SRI-4 response rates at Wk 52 were evaluated by BL characteristic subgroups: SELENA-SLEDAI score; SLE International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) score; disease duration; biomarker levels (anti-dsDNA, complement [C]3/C4); glucocorticoid (GC), immunosuppressant (IS), and antimalarial (AM) use.ResultsOverall, 3086 pts were included (BEL, n=1869; PBO, n=1217). Most were female (94.4%); mean (standard deviation [SD]) age was 37.0 (11.6) years. Mean (SD) SLE duration was 6.4 (6.4) years.At Wk 52, in the overall population, significantly more BEL vs PBO pts were SRI-4 responders (Figure 1). A significantly greater proportion of SRI-4 responders was observed with BEL vs PBO as early as Wk 8 (38.4% vs 33.3%; odds ratio, OR [95% confidence interval, CI] 1.25 [1.07, 1.46]; p=0.0060), which continued to increase to Wk 52 (54.8% vs 41.6%; OR [95% CI] 1.70 [1.46, 1.98]; p<0.0001). At Wk 52, more BEL vs PBO pts had a 4-point reduction in SELENA-SLEDAI (56.3% vs 43.1%; OR [95% CI] 1.71 [1.47, 2.00]; p<0.0001), no worsening in PGA (76.6% vs 67.9%; OR [95% CI] 1.52 [1.28, 1.79]; p<0.0001), and no new BILAG 1A/2B organ domain scores (77.1% vs 69.4%; OR [95% CI] 1.47 [1.25, 1.74]; p<0.0001). Pts on BEL were 52% more likely to experience an SRI-4 response that was maintained through Wk 52 (hazard ratio, HR [95% CI] 1.52 [1.36, 1.69]; p<0.0001).Figure 1.SRI-4 response at Wk 52 in the overall population and by BL characteristic subgroups.*OR (95% CI) and p-value are from a logistic regression model for BEL vs PBO comparison with covariates of treatment group, study and BL SELENA-SLEDAI score (≤9 vs ≥10)SRI-4 response rates were significantly higher with BEL vs PBO in most subgroups, with the highest response rates observed in pts with SELENA-SLEDAI score of ≥10, low C3 and/or C4 + anti-dsDNA ≥30 IU/ml, and low C3 and/or C4 at BL (Figure 1).ConclusionSignificantly more pts receiving BEL had SRI-4 response rates that occurred from Wk 8 and were maintained through Wk 52 compared with pts receiving PBO. The efficacy of BEL was consistent across multiple pt subgroups, with higher response rates in pts with SELENA-SLEDAI scores of ≥10, low C3 and/or C4 + anti-dsDNA ≥30 IU/ml and low C3 and/or C4 at BL. These results further substantiate the benefits of BEL in the treatment of adults with SLE.References[1]GlaxoSmithKline. Benlysta US prescribing information. 2021[2]Furie R, et al. Arthritis Rheumatol 2011;63(12):3918–30[3]Navarra SV, et al. Lancet 2011;377(9767):721–31[4]Stohl W, et al. Arthritis Rheum 2017;69(5):1016–27[5]Zhang F, et al. Ann Rheum Dis 2018;77(3):355–63[6] Ginzler E, et al. Arthritis Rheum 2021; doi: 10.1002/art.41900AcknowledgementsThis analysis was funded by GlaxoSmithKline (GSK). Medical writing support was provided by Lulu Hill, MPharmacol, Fishawack Indicia Ltd. UK, part of Fishawack Health, and was funded by GSK.Disclosure of InterestsMichelle A Petri Consultant of: GSK, Grant/research support from: GSK, George Bertsias Speakers bureau: Pfizer, Aenorasis, UCB, Novartis, Lilly, SOBI, Consultant of: Novartis, GSK, AstraZeneca, Grant/research support from: GSK, Pfizer, Mark Daniels Shareholder of: GSK, Employee of: GSK, Norma Lynn Fox Shareholder of: GSK, Employee of: GSK, Bevra H. Hahn Consultant of: UCB, GSK, Anne Hammer Shareholder of: GSK, Employee of: GSK, Julia Harris Shareholder of: GSK, Employee of: GSK, Holly Quasny Shareholder of: GSK, Employee of: GSK, Chiara Tani Speakers bureau: GSK, AstraZeneca, Anca Askanase Consultant of: AstraZeneca, Aurinia Pharmaceuticals Inc., Amgen, AbbVie Inc., BMS, GSK, Grant/research support from: AstraZeneca, Eli Lilly and Company, GSK, Idorsia Pharmaceuticals Ltd, Janssen Pharmaceuticals, Pfizer