Low disease activity-irrespective of serologic status at baseline-associated with reduction of corticosteroid dose and number of flares in patients with systemic lupus erythematosus treated with belimumab: A real-life observational study.

BACKGROUND: Low disease activity is a validated target of current systemic lupus erythematosus (SLE) therapy. The aim of this study was to assess the ability of belimumab to achieve low disease activity states in real-life settings. METHODS: Multicentre prospective observational study of consecutive SLE patients receiving belimumab for at least 3 months, due to active disease refractory to at least one conventional immunosuppressant. Disease activity, including the recently defined lupus low disease activity state (LLDAS) and remission (clinical SLEDAI-2K = 0), accrual of organ damage, flares and side effects were documented. RESULTS: Ninety-one patients were included [94.5% women, mean (SD) age 45.9 (12.5) years]. Most frequent manifestations were arthritis (76.7%), rash (72.5%), serologic activity (low C3/C4 and/or high anti-dsDNA; 54.9%), hair loss (47.2%) and mucosal ulcers (27.5%). Median (range) duration of treatment was 10.5 (3.0-42.1) months. Belimumab significantly decreased average SLEDAI-2K, physician global assessment (PGA) and daily prednisone dose over time, as early as 3 months after initiation, with over 20% of patients discontinuing corticosteroids. Although reduction in clinical (i.e., excluding serology) SLEDAI-2K was more pronounced in patients who were serologically active (from 8 to 1.5 at 12 months) as compared to serologically inactive (from 6 to 4) at baseline, attainment of LLDAS did not differ between the two groups and was reached by more than 40% of completer patients after 9-12 months. In addition, the number of flares and severe flares was reduced by 62% and 50%, respectively, during the first 12 months of treatment. Twenty patients (22.0%) discontinued treatment due to inadequate response and two due to side effects potentially related to the drug. CONCLUSIONS: In real-life, belimumab is efficacious in achieving low disease activity in over 40% of unselected patients, in combination with reduction of corticosteroid dosage and number of flares. Both serologically active and inactive patients respond to the drug.