U.S. clears new lupus drug, blockbuster sales seen

(Reuters) - The first new treatment for lupus in a half-century won U.S. approval on Wednesday, a milestone for patients with the disabling disease and a potential blockbuster for tiny biotech company Human Genome Sciences Inc.

Health officials cleared Benlysta for certain patients with active lupus who are receiving standard therapy. The disease causes the immune system to attack joints and organs and has proved tough to study and treat.

Human Genome will split profits from the drug with GlaxoSmithKline Plc. Benlysta's annual global sales may top $3 billion in 2015, according to Thomson Reuters consensus forecasts.

Glaxo shares rose 3.4 percent in after-hours trading to $39.90, up from an earlier close of $38.58 in regular trading on the New York Stock Exchange. Human Genome shares remained halted.

In clinical trials, black patients "did not appear to respond to treatment," the Food and Drug Administration said, adding that the studies "lacked sufficient numbers to establish a definite conclusion."

To address that concern, the company will run another study to further examine safety and effectiveness in black patients, the agency said.

More deaths and serious infections were reported with Benlysta compared with a placebo in clinical studies. The company must provide a patient-friendly guide explaining the risks, the FDA said.

"Benlysta, when used with existing therapies, may be an important new treatment approach for health care professionals and patients looking to help manage symptoms associated with this disease," Dr. Curtis Rosebraugh, head of the FDA office that reviewed the drug, said in a statement.

Lupus causes a range of symptoms including arthritis, kidney damage, chest pain, skin rashes, severe fatigue and other problems. Symptoms often wax and wane. The organ damage can be fatal.

An estimated 5 million people worldwide have the disease. Current drugs often fail to help or cause harsh side effects, such as severe bone loss from steroids.

(Reporting by Lisa Richwine in Washington and Bill Berkrot in New York; Editing by Tim Dobbyn)