Human Genome Sciences and GlaxoSmithKline announced that Benlysta (belimumab, formerly LymphoStat-B) met the primary endpoint in BLISS-76, the second of two pivotal Phase 3 trials in seropositive patients with systemic lupus erythematosus (SLE). This study was a double-blind, placebo-controlled, multi-center of 819 patients at 136 clinical sites in 19 countries, primarily in North America and Europe. The primary efficacy endpoint of BLISS-76 (and an earlier study BLISS-52) was the patient response rate at Week 52 as measured by the SLE Responder Index, which is defined by: (1) a reduction from baseline of at least 4 points on the SELENA SLEDAI disease activity scale (which indicates a clinically important reduction in SLE disease activity); (2) no worsening of disease as measured by the Physician’s Global Assessment (worsening defined as an increase of 0.30 points or more from baseline); (3) no new BILAG A organ domain score (which indicates a severe flare of lupus disease activity) and no more than one new BILAG B organ domain score (which indicates a moderate flare of disease activity).
Based on an intention-to-treat (ITT) analysis, a statistically significant improvement was shown in patient response rate for belimumab 10 mg/kg plus standard of care, vs. placebo plus standard of care, as measured by the SLE Responder Index at Week 52: 43.2% for 10 mg/kg belimumab, 40.6% for 1 mg/kg belimumab, and 33.8% for placebo (p=0.021 and p=0.10 for 10 mg/kg and 1 mg/kg belimumab, respectively vs. placebo). The 1 mg/kg dose plus standard of care did not achieve statistically significant improvement in the current study. The SLE Responder Index defines patient response as an improvement in SELENA SLEDAI score of 4 points or greater, with no clinically significant BILAG worsening and no clinically significant worsening in Physician’s Global Assessment.
Benlysta is a human monoclonal antibody drug that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator (BLyS). BLyS is a naturally occurring protein required for the development of B-lymphocyte cells into mature plasma B cells that produce antibodies. In SLE, elevated levels of BLyS are believed to contribute to the production of autoantibodies.