Effectiveness of belimumab in reducing disease activity in patients with refractory systemic lupus erythematosus: Real-world evidence.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a chronic, heterogeneous, multisystem autoimmune disease associated with high morbidity and mortality rates, as well as significant cumulative organ damage. This is particularly true in patients with persistent disease activity that does not respond to conventional therapy. This study evaluated the use of belimumab in a real-world clinical practice setting. METHODS: This was an ambispective, longitudinal, observational cohort study with an intra-individual analysis. Thirty-three adult patients with refractory SLE were included in the study and followed for up to 18 months. Refractory disease was defined as persistent clinical and/or serological activity despite prior standard therapy. This therapy included glucocorticoids and antimalarials when indicated, either alone or in combination with conventional immunosuppressive therapy. Other inclusion criteria were failure to achieve therapeutic targets, recurrent flares, and an inability to taper corticosteroids. These criteria were determined through a retrospective review of medical records. RESULTS: There was a significant reduction in disease activity, as evidenced by a decrease in the SLEDAI-2K score from 11.4 to 4.0. Additionally, there was a corticosteroid-sparing effect, as demonstrated by a reduction in the mean prednisone dose from 26.5mg to 3.2mg. A favorable longitudinal trend was observed for C3, C4, and anti-dsDNA. However, these biomarker findings should be interpreted in light of the descriptive nature of the available laboratory follow-up. In the subgroup with lupus nephritis, renal parameters remained stable during follow-up. Due to the small sample size and the lack of standardized renal response criteria for all patients, these results should be interpreted with caution and are not indicative of renal efficacy. CONCLUSION: In this real-world cohort of patients with refractory SLE, belimumab use was associated with lower disease activity and reduced prednisone exposure during the follow-up period. Longitudinal trends in immunological biomarkers were favorable.