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Lupus drug Benlysta passes second crucial test

November 2, 2009 |  3:56 pm

Benlysta, a new drug designed specifically to treat systemic lupus erythematosus, commonly called simply lupus, has passed a second clinical trial, paving the way for it to become the first new treatment approved for lupus in 50 years. Its maker, Human Genome Sciences of Rockville, Md., said that it would apply to the Food and Drug Administration for approval of the drug in the first half of next year and that it expects approval sometime in 2010.

"This is spectacular news for the worldwide lupus community," said Dr. Tammy O. Utset of the University of Chicago. "These trials demonstrate that SLE can be studied successfully in a clinical trial setting and should encourage further interest in drug development for lupus, an area of great unmet need."

Lupus, which affects an estimated 160,000 Americans and as many as 5 million worldwide, is an autoimmune disorder in which the body's immune system attacks its own tissues and organs, causing a host of symptoms, including arthritis, kidney damage, chest pain, fatigue and a characteristic skin rash that some early doctors thought resembled wolf bites ("lupus" means wolf in Latin). Treatments involve steroids and a variety of other drugs that alleviate symptoms, but that have a variety of side effects, many of them severe.

Benlysta, known generically as belimumab, is an artificially generated monoclonal antibody that inhibits the biological activity of a naturally occurring protein called B-lymphocyte stimulator or BLyS.  BLyS is required for the creation of plasma B cells that produce the antibodies that attack organs.

Results reported in July from a clinical trial involving 860 patients in Asia, South American and Eastern Europe showed that the drug reduced the severity of symptoms and reduced the amount of steroids that patients required.

The second trial, whose results were announced today by the company, involved 816 patients at 19 centers, primarily in North America and Europe. Researchers found that 43.2% of those taking the highest dose of Benlysta in addition to standard therapy had a significant reduction in symptoms with no worsening of the disease in organs. That compares with 33.8% of those taking a placebo in addition to standard care. Most of the patients, though, were not able to reduce their steroid use, but that was not a primary endpoint of the trial and failure to achieve it is not likely to prevent approval of the drug.

That approval is likely once the application is filed because the company worked closely with the FDA to define the necessary endpoints that would indicate successful treatment. Those endpoints were met in both trials.

The chief drawbacks of the drug are that it must be given monthly by infusion and its price. The company has not said what it will charge, but monoclonal antibodies now on the market cost thousands of dollars per dose, and Benlysta is unlikley to be any cheaper. Analysts project its annual sales will be more than $1 billion.

-- Thomas H. Maugh II