Human Genome Sciences, Inc announced the presentation of results from a long-term phase-2 continuation trial showing that Benlysta (belimumab, formerly LymphoStat-B) was associated with sustained improvement in disease activity across multiple clinical measures, decreased frequency of disease flares, and was generally well tolerated through four years on treatment in combination with standard of care in patients with serologically active systemic lupus erythematosus (SLE). The results were presented in Copenhagen at the 2009 Congress of the European League Against Rheumatism (EULAR).

"Based on the results presented at EULAR 2009, the apparent durability of clinical effect and the favourable safety profile observed for belimumab suggest that belimumab has the potential to become an important new treatment for patients with SLE," said Joan T Merrill, a study investigator, programme chair, Clinical Pharmacology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, and professor, Department of Medicine, University of Oklahoma Health Sciences Center.

SLE is a chronic, life-threatening autoimmune disease. It is estimated that approximately 1.5 million people in the United States and approximately five million worldwide suffer from various forms of lupus, including SLE.

"We are encouraged by the sustained improvement in serologically active SLE patients treated with belimumab through four years," said William W Freimuth, vice president, Clinical Research - Immunology, Rheumatology and Infectious Diseases. "We are also encouraged by the safety data presented at EULAR. The incidence rates per 100 patient years of all adverse event categories, including serious adverse events, overall adverse events, and serious infections were similar for belimumab and placebo during the 52-week double-blind period, and remained the same or decreased over four years of continuous treatment. Belimumab could represent a significant advance in the treatment of SLE if phase-2 results are confirmed in the phase-3 trials that are currently ongoing."
Benlysta Selected as Belimumab Brand Name; phase-3 Results Expected in July and November 2009

HGS and GlaxoSmithKline (GSK) have selected Benlysta as the brand name for belimumab (formerly known as LymphoStat-B). HGS and GSK expect to report the first phase-3 data for Benlysta in July 2009 from the BLISS-52 trial, with results from BLISS-76 anticipated in November 2009. BLISS-52 and BLISS-76 are the largest clinical trials ever conducted in lupus patients. Benlysta is being developed by HGS and GSK under a co-development and commercialization agreement entered into in August 2006.
The data presented at EULAR 2009 showed that continued treatment with belimumab (Benlysta) is associated with sustained improvement or stabilization of SLE disease activity and with decreased frequency of SLE disease flares in serologically active patients through four years of treatment. The overall incidence of adverse events (in general and by system organ class), serious adverse events, infections, malignancies and laboratory abnormalities decreased or stabilized over time from Week 52 to Week 208.

The data presented at EULAR 2009 suggest that belimumab was generally well tolerated and may be safely administered long-term in patients with SLE. By Week 208, overall belimumab exposure was 1192 patient years. The incidence rates per 100 patients in all adverse event categories, including serious adverse events, overall adverse events, and serious infections, were similar for belimumab and placebo during the 52-week double-blind period, and remained the same or decreased over four years of continuous treatment.

Benlysta is a human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, or BLyS.