Effect of belimumab treatment on renal outcomes: results from the phase 3 belimumab clinical trials in patients with SLE

A pooled post-hoc analysis of the phase 3, randomized, placebo-controlled BLISS trials (1684 patients with active systemic lupus erythematosus (SLE)) was performed to evaluate the effect of belimumab on renal parameters in patients with renal involvement at baseline, and to explore whether belimumab offered additional renal benefit to patients receiving mycophenolate mofetil at baseline. In addition to belimumab or placebo, all patients received standard SLE therapy. Patients with severe active lupus nephritis were excluded from the trials. Over 52 weeks, rates of renal flare, renal remission, renal organ disease improvement (assessed by Safety of Estrogens in Lupus Erythematosus National Assessment–Systemic Lupus Erythematosus Disease Activity Index and British Isles Lupus Assessment Group), proteinuria reduction, grade 3/4 proteinuria, and serologic activity favored belimumab, although the between-group differences in most renal outcomes were not significant. Among the 267 patients with renal involvement at baseline, those receiving mycophenolate mofetil or with serologic activity at baseline had greater renal organ disease improvement with belimumab than with placebo. Limitations of this analysis included the small patient numbers and the post-hoc nature of this pooled analysis. The results suggest that belimumab may offer renal benefit in patients with SLE. Further study is warranted in patients with severe active lupus nephritis.