Efficacy and safety of belimumab in patients with lupus nephritis: a real-world retrospective observational study.

Objectives: To evaluate the differences in efficacy and safety between Lupus Nephritis (LN) patients who received belimumab plus standard therapy and those who received only standard therapy in real world practice.

Methods: Patients diagnosed with LN at the First Affiliated Hospital of Wenzhou Medical University from November 2012 to July 2023 were identified, and eligible cases were divided into two groups according to whether they received additional treatment with belimumab during the course of the disease.

Results: A total of 1,169 LN patients were identified from our follow-up database. 112 patients receiving add-on treatment with belimumab (BLM group) and 112 control patients matched for relevant baseline characteristics were enrolled in this study. The median duration of treatment with belimumab was 13.82 [7.24, 20.29] months. Compared with the control group, the BLM group had more significant improvement in disease activity indicators such as serum albumin and complement levels, significantly lower B cell count, immunoglobulin, and earlier first attainment of renal remission, but there was no significant improvement in renal function and kidney-related events or death during the 2-year follow-up period. In the BLM group, the treatment effect of belimumab was more prominent in patients with lower levels of proteinuria. The safety profile of belimumab treatment was favorable, with a lower incidence of respiratory tract infection in the BLM group than in the control group during the follow-up period (p= 0.015).

Conclusions: This real-world study revealed that add-on treatment with belimumab provided better disease remission, and the therapeutic effect was more significant in patients with lower proteinuria levels. In addition, it had a favorable safety profile and reduced the risk of respiratory tract infection.