We performed a post hoc analysis of the Belimumab International Study in Lupus 
Nephritis (BLISS-LN), a Phase 3, multinational, double-blind, 104-week trial, in 
which 448 patients with lupus nephritis were randomized to receive intravenous 
belimumab 10 mg/kg or placebo with standard therapy 
(cyclophosphamide/azathioprine or mycophenolate mofetil). Add-on belimumab was 
found to be most effective in improving the primary efficacy kidney response and 
complete kidney response in patients with proliferative lupus nephritis and a 
baseline urine protein/creatinine ratio under 3 g/g. However, there was no 
observed improvement in the kidney response with belimumab treatment in patients 
with lupus nephritis and sub-epithelial deposits or with a baseline 
protein/creatinine ratio of 3 g/g or more. Belimumab significantly reduced the 
risk of kidney-related events or death and lupus nephritis flare in the overall 
population. Belimumab reduced the risk of a sustained 30% or 40% decline in 
estimated glomerular filtration rate (eGFR) versus standard treatment alone and 
attenuated the annual rate of eGFR decline in patients who remained on-study. 
Thus, our data suggest that the addition of belimumab to standard therapy could 
attenuate the risk of lupus nephritis flare and eGFR decline in a broad spectrum 
of patients with lupus nephritis.