GlaxoSmithKline PLC (GSK) and Human Genome Sciences (HGS), Inc announced that Benlysta (belimumab) met the primary endpoint in BLISS-76, the second of two pivotal phase-3 trials in seropositive patients with systemic lupus erythematosus (SLE). BLISS-76 study results through 52 weeks showed that belimumab 10 mg/kg plus standard of care achieved a statistically significant improvement in patient response rate as measured by the SLE Responder Index at Week 52, compared with placebo plus standard of care. Study results also showed that belimumab was generally well tolerated, as demonstrated by a similar rate of discontinuations due to adverse events across treatment groups, with overall adverse event rates comparable between belimumab and placebo treatment groups.

"The BLISS-76 results confirm our view that Benlysta has the potential to become the first new approved drug in decades for people living with systemic lupus," said H Thomas Watkins, president and chief executive officer, HGS. "We take great pride in the innovation and scientific rigour that has made it possible to bring Benlysta to this point. We plan to submit marketing applications in the first half of 2010, following discussions with regulatory authorities in the United States, Europe and other regions. We will continue to work with GSK to advance this drug to the market where it may benefit patients with significant need."

Carlo Russo, senior vice president, Biopharm Development, GSK, said, "The results from this second pivotal phase 3 trial reinforce our belief that belimumab could deliver a significant therapeutic option for patients with lupus who have had no new treatment in 50 years. We look forward to continuing our collaboration with HGS in order to bring this important medicine to patients."

The data from the BLISS-76 study were analysed after 52 weeks, in accordance with the study protocol, in support of a potential Biologics License Application in the United States and Marketing Authorisation Applications in Europe and other regions. However, the BLISS-76 study is ongoing and will continue for 24 more weeks. Additional data will be available following completion of the full 76-week study period. Belimumab is an investigational drug and the first in a new class of drugs called BLyS-specific inhibitors. Belimumab is being developed by HGS and GSK under a co-development and commercialisation agreement entered into in August 2006.

"We are delighted that the efficacy of treatment with belimumab plus standard of care was superior to placebo plus standard of care in both BLISS-52 and BLISS-76, with overall adverse event rates comparable to placebo plus standard of care," said David C Stump, executive vice president, Research and Development, HGS. "Belimumab met the primary endpoint in both pivotal phase-3 trials, as specified by the Special Protocol Assessment Agreement with the FDA. We look forward to the full presentation of the BLISS-76 52-week results at an appropriate scientific meeting, hopefully in the first half of 2010."

"The lupus community has waited for decades for one positive Phase 3 trial of an investigative drug developed for lupus. Now we have two. Based on the data we now have in hand, we have cause for hope that belimumab may emerge as a significant new treatment for lupus," said Joan T Merrill, a study investigator, programme chair, Clinical Pharmacology Research Programme, Oklahoma Medical Research Foundation, Oklahoma City, and Professor, Department of Medicine, University of Oklahoma Health Sciences Centre.

Belimumab is an investigational human monoclonal antibody drug that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, or BLyS.

Systemic lupus erythematosus (SLE) is a chronic, life-threatening autoimmune disease.