Administration of belimumab prior to standard immunosuppression in patients with early active lupus hinders accrual of new EULAR/ACR criteria within the first 12 months of treatment

Objective To evaluate the effect of early belimumab administration on disease progression in patients with early active SLE.Methods This multicentre observational study included patients with early active SLE, defined as being diagnosed <= 12 months from enrolment in the study, displaying <= 2 clinical European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) 2019 criteria, without major organ involvement but with active serology. Patients were receiving glucocorticoids and hydroxychloroquine as standard of care (SoC) and either belimumab (BEL group) or standard immunosuppression (SoC group). Patients were followed up for 12 months, and accrual of new EULAR/ACR criteria served as a marker of disease progression. Kaplan-Meier survival analysis and log-rank tests were applied to assess differences in criteria-free survival between groups, while Cox regression compared the lag time to criteria accrual.Results 69 patients were included (BEL=33 and SoC=36). Patients receiving early BEL accrued fewer events per 100 patient-years compared with SoC (2.78 vs 12.12, p=0.035). Criteria-free survival was longer in the BEL group (log-rank p=0.04), with a mean time-to-event of 11.8 +/- 1.07 months versus 10.3 +/- 3.33 months in the SoC group (Cox regression, p=0.027). Early BEL was associated with a sixfold higher likelihood of achieving glucocorticoid (GC) discontinuation at 12 months as compared with patients on hydroxychloroquine (HCQ) and GC alone (OR 6.67, p=0.0014).Conclusions Early administration of BEL in active SLE significantly delays disease progression and promotes GC withdrawal. These findings are more striking when limiting SoC to HCQ and GC and underscore the potential of early biologic intervention to modify disease course. Further validation in larger, prospective studies is warranted.