106 Effects of belimumab on corticosteroid use in a pivotal phase iii, randomised, placebo controlled study in subjects with systemic lupus erythematosus in north east asia

Background and aims Steroid reduction is an important treatment goal in systemic lupus erythematosus (SLE). The steroid-sparing effects of belimumab were investigated in subjects in North East Asia. Methods This multicentre, 52 week study (1 13 750/NCT01345253) randomised (2:1) subjects (≥18 years) with SELENA-SLEDAI ³8 to intravenous belimumab 10 mg/kg or placebo every 28 days, plus standard SLE therapy. Multiple measures of steroid use (prednisone equivalent) were made, including a secondary endpoint of reduction in dose over 52 weeks among subjects receiving >7.5 mg/day at baseline (number of days≤7.5 mg/day and/or dose reduced by 50% from baseline). The primary endpoint was SLE Responder Index response rate at Week 52 (reported elsewhere). Results Baseline prednisone doses were similar between groups (Table 1). Across the population, cumulative prednisone dose over 52 weeks was significantly lower in the belimumab group versus placebo (p=0.0005; Table 1. For subjects with baseline dose >7.5 mg/day, the median number of days that prednisone dose was ≤7.5 mg/day and/or reduced by 50% was zero in both groups; however, the 75 th percentile was larger for belimumab (213.5 days) versus placebo (172.0), reflecting the subjects who achieved longer durations of reduced steroid use within the belimumab group (p=0.0288; Figure 1). More subjects in the belimumab group had a dose reduction of ≥25% to ≤7.5 mg/day during Weeks 40–52 (belimumab, 15.6%; placebo, 10.9%: p=0.0721). Adverse event incidences were similar (belimumab, 75.7%; placebo, 74.9%). Conclusions These results suggest belimumab is more effective than placebo in reducing steroid use across 52 weeks in this population. Study funded by GSK.