Disease Control and Safety of Belimumab Plus Standard Therapy Over 7 Years in Patients with Systemic Lupus Erythematosus

Objective. To evaluate the efficacy/safety of belimumab plus standard therapy in patients (n = 449) with active systemic lupus erythematosus (SLE) treated up to 7 years (n = 177 currently ongoing). Methods. Patients (n = 345) who completed a double-blind, placebo-controlled, 52-week study of belimumab 1, 4, or 10 mg/kg and 24-week extension of belimumab (placebo switched to 10 mg/kg; belimumab same dose or switched to 10 mg/kg) could receive belimumab 10 mg/kg in an open-label continuation study (n = 296). Disease activity was analyzed in patients with active SLE at baseline of the initial study. Biomarker and SLE medication changes were evaluated, and adverse events (AE) were monitored throughout the study. Results. Total belimumab exposure over 7 years (double-blind and open-label periods): 1746 patient-years. SLE Responder Index (SRI) response rates at Week 52 in autoantibody-positive patients: placebo, 29%; belimumab, 46% (p < 0.05). In the continuation study, 57% of auto-antibody-positive patients had an SRI response by Year 2 and 65% by Year 7; severe flares occurred in 19% with placebo and 17% with belimumab during the first year, with the annual rate declining to 2%–9% during years 2–7. Anti-dsDNA autoantibodies in patients positive for them at baseline had a progressive decline of 40%–60% from baseline over 2–7 years with belimumab. Corticosteroid use decreased over time with ≥ 50–55% reduction in median dose during years 5–7. Serious and overall annual AE rates, including infections, were generally stable or decreased during 7-year treatment. Conclusion. Disease control and safety profile were maintained in patients with active SLE taking belimumab plus standard therapy for up to 7 years. [ ClinicalTrials.gov numbers: NCT00071487 and NCT00583362 ]