Lupus Drug Shows Promise

A treatment for lupus, a chronic disease that causes pain, inflammation, and tissue damage across the body when the immune system goes awry, might finally be on the horizon. Last week, Human Genome Sciences (HGS) and partner GlaxoSmithKline (GSK) said that their lupus drug candidate Benlysta was safe and effective in a late-stage clinical trial.

"Benlysta could be the first true disease-modifying therapy for lupus patients," says Joseph P. Schwartz, a stock analyst at Leerink Swann.

For decades, lupus patients, who are overwhelmingly women, have had to treat the symptoms of their disease with old drugs such as nonsteroidal anti-inflammatories, corticosteroids, antimalarials, or, in severe cases, immunosuppressive drugs.

Benlysta is a human monoclonal antibody that blocks the B-lymphocyte stimulator, a protein needed for a type of white blood cell to mature into plasma B cells, which make antibodies. HGS discovered B-lymphocyte stimulator in 1999 and worked with Cambridge Antibody Technology, now part of AstraZeneca, to develop a monoclonal antibody that stems the stimulator's role in an overactive immune system.

Last week, HGS's stock price more than quadrupled on the news that adding Benlysta to a patient's treatment regime significantly stabilized or reduced symptoms of the disease. At the same time, the drug was shown to be safe and well tolerated.

Sandra C. Raymond, CEO of the Lupus Foundation of America, called the announcement of the trial results a "historic day" for people with lupus. "These results provide hope that this complex chronic autoimmune disease can be brought under control and that, eventually, a cure can be found for the estimated 1.5 million Americans and more than 5 million people worldwide living with lupus," she said in a statement.

HGS expects to file for regulatory approval to sell Benlysta in the first half of 2010, with a launch likely in early 2011. Thomas Weisel Partners stock analyst M. Ian Somaiya expects that the drug could bring in $2 billion in annual sales by 2015—and even more if doctors use it off-label for milder forms of the disease.

Success for Benlysta could have big implications for HGS, which is seen as having floundered in recent years. Somaiya notes that three of HGS's five late-stage drug candidates are being developed in partnership with GSK, raising the possibility that approval of Benlysta could spur GSK to acquire the biotech firm.