The 104-week, randomized, double-blind, placebo-controlled trial compared the efficacy and safety of belimumab 10mg/kg intravenous (IV) plus standard therapy (mycophenolate mofetil for induction and maintenance, or cyclophosphamide for induction followed by azathioprine for maintenance, plus steroids) with placebo plus standard therapy in 448 adult patients with lupus nephritis. The primary outcome measure was primary efficacy renal response (PERR), defined as eGFR ≥60mL/min/1.73m2 or no decrease in eGFR from pre-flare of >20%; and urinary protein: creatinine ratio (uPCR) ≤0.7; and not a treatment failure.
Results showed that the belimumab treatment arm met the primary end point with a significantly greater number of patients achieving PERR over 2 years compared with placebo (43% vs 32%; odds ratio [95% CI] 1.55 [1.04, 2.32]; P =.0311). Moreover, belimumab demonstrated statistical significance for all 4 key secondary end points, which included complete renal response after 2 years, ordinal renal response after 2 years, PERR after 1 year, and the time to death or renal-related event.
With regard to safety, adverse events were observed to be similar between the belimumab and placebo groups and consistent with the safety profile for belimumab.
Full detailed results will be submitted for future presentation at upcoming scientific meetings and in peer-reviewed publications. The Company plans to submit regulatory applications in the first half of 2020 to seek approval for the lupus nephritis indication.
Belimumab (Benlysta), a B-Lymphocyte stimulator (BLyS)-specific inhibitor, is already indicated for the treatment of active, autoantibody-positive systemic lupus erythematosus in patients aged ≥5 years receiving standard therapy.
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