Background/Purpose: Belimumab (BEL) is approved for the treatment of active SLE, and lupus nephritis, with standard therapy.¹ The prevalence and severity of SLE tend to be higher in patients of Black and Asian race, and Hispanic ethnicity, compared with Caucasians.² This large integrated analysis investigated BEL efficacy by race and ethnicity in patients with SLE.

Methods: This Belimumab Summary of Lupus Efficacy (Be-SLE) post hoc analysis pooled data from five BEL trials: BLISS-76³ (GSK study BEL110751); BLISS-52⁴ (BEL110752); NEA⁵ (BEL113750); BLISS-SC⁶ (BEL112341); EMBRACE⁷ (BEL115471; study in patients of self-identified Black race). Included patients received BEL (10 mg/kg/month intravenously or 200 mg/week subcutaneously) or placebo (PBO), plus standard therapy. The proportion of patients with SLE Responder Index-4 (SRI-4) response at Week 52, and time to first severe Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA)-SLEDAI Flare Index (SFI) flare, SFI flare, and BILAG (1A/2B) flare over 52 weeks were analyzed by race (Asian, White, Black African ancestry) and ethnicity (Hispanic/Latino, non-Hispanic/Latino).

Results: Among 3086 patients (BEL, n=1869; PBO, n=1217), 35.7% (BEL, n=697; PBO, n=405) were Asian, 33.4% (BEL, n=596; PBO, n=436) were White, and 20.5% (BEL, n=405; PBO, n=229) were of Black African ancestry. For ethnicity, 27.4% (BEL, n=495; PBO, n=352) were Hispanic/Latino and 72.6% (BEL, n=1374; PBO, n=865) were not Hispanic/Latino. At Week 52, higher proportions of BEL-treated patients were SRI-4 responders and fewer BEL-treated patients experienced severe SFI flares in all subgroups versus PBO, with statistically significant differences in all subgroups except patients of Black African ancestry (Table). Greatest treatment differences were among Hispanic/Latino and White patients. Fewer BEL-treated patients experienced SFI and BILAG (1A/2B) flares in all subgroups versus PBO; however, statistical significance was not reached for SFI in the Black African ancestry subgroup and for BILAG (1A/2B) among the White and Black African ancestry subgroups (Table).

Conclusion: BEL significantly increased SRI-4 response rates at Week 52 and decreased flares versus PBO in most subgroups by race and ethnicity, which was largely consistent with results from the overall populations of the primary trials. Numerical benefit only observed in Black African ancestry patients was consistent with the EMBRACE trial findings,⁷ from which most patients in this subgroup originated. This analysis was limited by low power to detect statistically significant differences in the smallest subgroup. Collectively, this analysis in a large, diverse population of patients with SLE continues to support the efficacy of BEL

Funding: GSK

References
1 GSK. Benlysta US prescribing information. 2023
2 Lewis MJ, Jawad AS. Rheumatol (Oxford) 2017;56:i67–i77
3 Furie R et al. Arthritis Rheumatol 2011;63(12):3918–30
4 Navarra SV et al. Lancet 2011;377(9767):721–31
5 Stohl W et al. Arthritis Rheumatol 2017;69(5):1016–27
6 Zhang F et al. Ann Rheum Dis 2018;77(3):355–63
7 Ginzler E et al. Arthritis Rheumatol 2021;doi:10.1002/art.41900

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/efficacy-of-belimumab-in-patients-with-systemic-lupus-erythematosus-by-race-and-ethnicity-a-large-post-hoc-integrated-analysis-of-five-clinical-trials/