Two-Year, Randomized, Controlled Trial of Belimumab in Lupus Nephritis.

BACKGROUND: In adults with active lupus nephritis, the efficacy and safety of intravenous belimumab as compared with placebo, when added to standard therapy (mycophenolate mofetil or cyclophosphamide-azathioprine), are unknown. METHODS: In a phase 3, multinational, multicenter, randomized, double-blind, placebo-controlled, 104-week trial conducted at 107 sites in 21 countries, we assigned adults with biopsy-proven, active lupus nephritis in a 1:1 ratio to receive intravenous belimumab (at a dose of 10 mg per kilogram of body weight) or matching placebo, in addition to standard therapy. The primary end point at week 104 was a primary efficacy renal response (a ratio of urinary protein to creatinine of ≤0.7, an estimated glomerular filtration rate [eGFR] that was no worse than 20% below the value before the renal flare (pre-flare value) or ≥60 ml per minute per 1.73 m2 of body-surface area, and no use of rescue therapy), and the major secondary end point was a complete renal response (a ratio of urinary protein to creatinine of