LAUSR

OBJECTIVES The efficacy of belimumab (BEL) during maintenance therapy in patients with systemic lupus erythematosus (SLE) remains unclear in the real-life clinical setting. This study investigated the efficacy and safety of BEL in patients with SLE during maintenance therapy. METHODS In this retrospective observational study, maintenance therapy was defined as low-dose glucocorticoid (GC) therapy (prednisolone equivalent dose of ≤ 0.2 mg/kg/day) in patients with a Safety of Estrogens in Lupus Erythematosus National Assessment-SLE Disease Activity Index (SELENA-SLEDAI) score <10. Participants comprised patients with SLE on hydroxychloroquine or mycophenolate mofetil (standard-of-care [SoC] group: n = 103) and those on BEL plus SoC (BEL+SoC group: n = 100). Selection bias was minimised using propensity score-based inverse probability of treatment weighting (IPTW). GC dose trajectories were modelled using growth mixture modelling (GMM). The primary endpoint was GC dose at 52 weeks. RESULTS No significant difference was observed in patient characteristics between the two groups after IPTW adjustment. The BEL+SoC group exhibited a significant decrease in GC dose. GC dose at 52 weeks and relapse rate were significantly lower in the BEL+SoC group than in the SoC group. The proportion of patients in one of four groups defined by GMM for which GC dose was tapered to 0 mg within 52 weeks (GC tapering-discontinuation group) was significantly higher in the BEL+SoC group than in the SoC group. In the BEL+SoC group, low SELENA-SLEDAI score and low GC dose at baseline were associated with being GC dose-tapering discontinuation. CONCLUSION The present study suggests that BEL is suitable for patients with SLE during maintenance therapy.