The phase II study results show that LymphoStat-B (belimumab) is safe and well tolerated, biologically active, and reduces the signs and symptoms of rheumatoid arthritis at a level of statistical significance.
The double-blind, placebo-controlled, multi-center phase II clinical trial was designed to evaluate the safety, optimal dosing, and efficacy of LymphoStat-B, a human monoclonal antibody to B-lymphocyte stimulator (BLyS), in patients with rheumatoid arthritis.
Efficacy was evaluated according to the American College of Rheumatology (ACR) criteria. The primary efficacy endpoint was the rate of ACR 20 response at Week 24 (the percentage of patients who achieved at least 20% improvement on the ACR-specified measures of disease activity).
The rate of ACR 20 response at Week 24 was 36% in the 1mg/kg active-treatment cohort, and 31% in all active-treatment groups combined – significantly higher than the 17% rate of improvement observed for the placebo group.
In addition, trends toward a drug benefit were observed in the 4mg/kg treatment group (28% ACR 20 response) and in the 10mg/kg treatment group (29% ACR 20 response).
Safety results show that LymphoStat-B is well tolerated with no clinically significant differences from placebo in adverse events, serious adverse events or laboratory abnormalities.
“Completion of this study marks the achievement of a key 2005 milestone for Human Genome Sciences,” said CEO Thomas Watkins. “The next milestone for LymphoStat-B is completion of the phase II trial in systemic lupus erythematosus, which we expect to achieve in the fall.”