Human Genome Achieves BLISS

HGSI’s Benlysta meets its endpoints in Bliss-52 phase III trial for lupus

Earlier today, Human Genome Sciences, Inc. (HGSI) and GlaxoSmithKline PLC (GSK) announced that Benlysta met the primary endpoint in BLISS-52, the first of two pivotal phase III trials in patients with serologically active systemic lupus erythematosus (SLE).

In the placebo-controlled BLISS-52 study, the results showed that Benlysta 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 Benlysta was generally well tolerated, with adverse event rates comparable between belimumab and placebo treatment groups.

As a reminder, HGSI and GSK is co-developing Benlysta as a potential treatment for SLE. Benlysta is a human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator (BLyS). BLyS is a naturally occurring protein discovered by HGS that is required for the development of B-lymphocyte cells into mature plasma B cells. Plasma B cells produce antibodies, the body’s first line of defense against infection.

In lupus, rheumatoid arthritis and certain other autoimmune diseases, elevated levels of BLyS are believed to contribute to the production of autoantibodies -- antibodies that attack and destroy the body’s own healthy tissues. The presence of autoantibodies appears to correlate with disease severity. Preclinical and clinical studies demonstrate that B-cell antagonists can reduce autoantibody levels and help control autoimmune disease activity.

In August 2006, HGSI entered into a definitive worldwide agreement with GSK for the co-development and commercialization of Benlysta. Pursuant to the agreement, HGS is responsible for conducting the Benlysta phase III trials, with assistance from GSK. The companies will share equally in phase III/IV development costs, sales and marketing expenses, and profits of any product commercialized under the agreement.

In February and May 2007, HGS initiated BLISS-76 and BLISS-52, two pivotal phase III trials of BENLYSTA. Both phase III trials are double-blind, placebo-controlled, multi-center phase III superiority trials to evaluate the efficacy and safety of BENLYSTA plus standard of care, versus placebo plus standard of care, in the treatment of patients with active SLE. The primary efficacy endpoint of both trials is the patient response rate at Week 52, as defined by a reduction from baseline in the SELENA SLEDAI score of at least 4 points, no worsening in Physician’s Global Assessment and no worsening in BILAG.

Important secondary endpoints will include the patient response rate at Week 76, the SF-36 Health Survey physical component summary score, fatigue measures and the percentage of patients with reduction from baseline in average prednisone dose at Weeks 40-52.

HGSI has completed the enrollment and initial dosing of 826 patients in BLISS-76 in August 2008. Data from BLISS-76 are expected in November 2009.

Results from the Bliss-52 study showed 57.6 percent of patients taking a high dose of Benlysta experienced an improvement in their symptoms, compared with 43.6 percent who took a placebo. The result was statistically significant and met the main goal of the clinical trial. Of patients who took a low dose of the drug, which is administered once a month by IV infusion, 51.7 percent showed improvement in their symptoms, a figure that was also statistically significant.

With positive data from the Bliss-52 trial, we are anticipating similar results from the Bliss-76 trial. The positive results reduce the risks greatly associated with Benlysta. It is anticipated that a BLA will be filed in the United States in 1H10. We expect the US approval in early 2011. If approved, we expect Benlysta to become a blockbuster for HGSI.

Positive data from the Bliss-52 study takes the company one step closer to being the first to have a new lupus drug approved in 50 years. Lupus affects about 1.5 million people in the United States and 5 million worldwide.

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