Efficacy and safety of belimumab in paediatric and adult patients with systemic lupus erythematosus: an across-study comparison

OBJECTIVE: To assess the efficacy and safety of belimumab in paediatric versus adult patients with systemic lupus erythematosus (SLE). METHODS: We performed across-study comparisons of patients with active SLE who received belimumab or placebo, plus standard therapy, in PLUTO (paediatric phase II) and BLISS-52, BLISS-76, BLISS-NEA and EMBRACE (adult phase III). Analysed efficacy data included Week 52 SLE Responder Index (SRI)-4 response rate (EMBRACE: SRI with modified Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) proteinuria scoring (SRI-S2K)); SRI-4 response rate (EMBRACE: SRI-S2K) according to baseline disease activity indicators (Safety of Estrogens in Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) score; anti-dsDNA/C3/C4 levels); Week 52 SRI-6 response rate; and time to first severe flare (SELENA-SLEDAI Flare Index) over 52 weeks. Safety data were compared for all aforementioned studies along with adult LBSL02 (phase II) and BLISS-SC (phase III). RESULTS: SRI-4 response rates were similar across the paediatric and adult studies; more belimumab-treated patients achieved SRI-4 responses versus placebo (PLUTO: 52.8% vs 43.6%; BLISS-52: 57.6% vs 43.6%; BLISS-76: 43.2% vs 33.8%; BLISS-NEA: 53.8% vs 40.1%; EMBRACE: 48.7% vs 41.6%). Across all studies, SRI-4 response rates were generally greater in patients with baseline SELENA-SLEDAI scores ≥10 than in patients with baseline SELENA-SLEDAI scores ≤9. A similar proportion of belimumab-treated patients achieved SRI-6 across all studies (PLUTO: 41.2%; BLISS-52: 46.2%; BLISS-76: 33.1%; BLISS-NEA: 43.9%; EMBRACE: 37.5%). Belimumab reduced the risk of severe flare versus placebo in all studies. The incidence of adverse events was similar across all studies. CONCLUSIONS: These analyses demonstrate consistent efficacy and safety of belimumab plus standard therapy across paediatric and adult patients with SLE. TRIAL REGISTRATION NUMBERS: PLUTO (NCT01649765); BLISS-52 (NCT00424476); BLISS-76 (NCT00410384); BLISS-NEA (NCT01345253); EMBRACE (NCT01632241); BLISS-SC (NCT01484496); and LBSL02 (NCT00071487).