Additional Relevant Details
For the primary efficacy endpoint (SLE Responder Index at Week 52), significantly more of the patients on belimumab 10mg/kg administered intravenously (54%) achieved reduced disease activity compared to those on placebo (40%) (Odds Ratio: 2.03; 95% CI: 1.43-2.88; p<0.0001). SRI is a comprehensive composite endpoint measure, the components of which measure reduction in disease activity defined as clinical improvement (³4‑point improvement in SELENA-SLEDAI, [SS]) with no significant worsening in any organ system (BILAG) and no worsening in overall patient condition (PGA).The benefits of belimumab were also seen for all the secondary endpoints in the study. The key secondary endpoint relating to average steroid reduction in patients with baseline dose of >7.5mg/day prednisone was significant (p=0.0228), favouring belimumab. In addition 56% of patients on belimumab achieved a ≥4 point reduction in SS at Week 52 (versus 42% on placebo, p=0.0001); 33% of belimumab patients achieved an SRI7 response rate (versus 23% on placebo, p=0.0099); and the belimumab group had a 50% lower risk of experiencing a severe flare versus placebo, as measured by the Severe Flare Index (p=0.0004).The safety profile of belimumab observed in the study was consistent with that observed in previous IV and subcutaneous belimumab studies, with the overall incidence of adverse events being similar in both the belimumab (75%) versus placebo (76%) groups. Fewer serious adverse events occurred in the belimumab group compared to the placebo group (12% versus 18%). There were no deaths in the belimumab group and 1 in the placebo group. No new safety issues were identified.