Human Genome Sciences, Inc and GlaxoSmithKline PLC (GSK) announced that Benlysta (belimumab, formerly LymphoStat-B) met the primary endpoint in BLISS-52, the first of two pivotal phase-3 trials in patients with serologically active systemic lupus erythematosus (SLE). In the placebo-controlled BLISS-52 study, the results showed that belimumab plus standard of care achieved a clinically and statistically significant improvement in patient response rate at Week 52, compared with standard of care alone. Study results also showed that belimumab was generally well tolerated, with adverse event rates comparable between belimumab and placebo treatment groups.

"The BLISS-52 results demonstrated 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. "Given the limited treatment options currently available, patients would benefit greatly from potential new treatments. Benlysta is an outstanding example of the type of treatment HGS is working to develop and bring to patients. Assuming positive results in November from our second phase-3 trial of Benlysta, we and GSK plan to submit marketing applications in the United States, Europe and other regions in the first half of 2010."

Belimumab is an investigational drug and the first in a new class of drugs called BLyS-specific inhibitors. No new drug for lupus has been approved by regulatory authorities in more than 50 years. Belimumab is being developed by HGS and GSK under a co-development and commercialization agreement entered into in August 2006.

"Lupus is a chronic, often debilitating, and sometimes fatal illness that affects an estimated five million people worldwide and can have a devastating effect on both patients living with the disease and their families," said Carlo Russo, senior vice president, Biopharm Development, GSK. "Benlysta is the first medicine being developed specifically for lupus that has reached this late stage of clinical development with positive results. We look forward to completing the pivotal studies, with the hope of bringing this potentially important therapeutic advance to patients suffering from SLE."

"The BLISS-52 results support and extend the findings that emerged in the serologically active subgroup of SLE patients at week 52 in our phase-2 trial," said David C Stump, executive vice president, Research and Development, HGS. "We are delighted to report that the efficacy of treatment with Benlysta plus standard of care was superior in this study to that of placebo plus standard of care, while the safety profile was comparable overall to placebo. Benlysta met the primary endpoint in this phase-3 study at a robust level of statistical significance. Benlysta also significantly reduced SLE disease activity versus placebo based on a number of other measures, including Selena Sledai and Physician's Global Assessment. Of note, a greater percentage of patients receiving Benlysta achieved a clinically meaningful reduction in steroid dose. We hope to have a full presentation of BLISS-52 results at an appropriate scientific meeting later in 2009."

Professor Sandra V Navarra, a principal investigator and head of Rheumatology at the University of Santo Tomas, Manila, The Philippines, said, "Given the limitations of available therapies, there is a great need for well tolerated and effective treatments for lupus. We are very encouraged by the findings of BLISS-52, and look forward to presenting these results later in the year. We also look forward to the results of BLISS-76 later this year."

The phase-3 development program for belimumab includes two double-blind, placebo-controlled, multi-center phase-3 superiority trials - BLISS-52 and BLISS-76 - to evaluate the efficacy and safety of belimumab plus standard of care, versus placebo plus standard of care, in serologically active (i.e., autoantibody-positive) patients with SLE.

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

The mission of HGS is to apply great science and great medicine to bring innovative drugs to patients with unmet medical needs.