Nov. 2 (Bloomberg) -- Human Genome Sciences Inc.’s experimental lupus drug Benlysta worked in a higher dose to reduce symptoms in a study. The company’s shares rose the most in more than three months.

Human Genome increased $6.59, or 35 percent, to $25.28 at 4:07 p.m. New York time in Nasdaq Stock Market composite trading.

No cure exists for lupus, which triggers the immune system to attack healthy cells and affects about 5 million people worldwide. Human Genome, based in Rockville, Maryland, said it will seek permission to sell the drug, marketed with London- based GlaxoSmithKline Plc, in the first half of next year. Benlysta may generate peak annual revenue of $1.5 billion, said Jeff Holford, a Jefferies International analyst.

“No drug has shown any impact on this disease in 50 years, so we think it likely that the Food and Drug Administration and other regulators will approve it rapidly,” said Kevin Wilson, a Citigroup analyst in London, in a research note today.

Patients in the study received one of two doses of the drug or a placebo. At 52 weeks, 43.2 percent of patients on the higher dose showed improvement, compared with 33.8 percent for the placebo group, Glaxo and Human Genome said in a statement today. Patients who received the lower dose didn’t show a statistically significant improvement, the companies said.

The study, Bliss-76, involved 819 patients. Tests are ongoing and further data will be announced after the 76-week study is completed, according to the statement.

Three Deaths

There were three deaths in the study, including one who was treated with the higher dose of Benlysta and two who were given the lower dose. Two patients on the higher dose, three who took the lower dose and one who was given a placebo developed tumors, the study showed.

Glaxo declined 20 pence, or 1.6 percent, to 1,230 pence as of 11:06 a.m. in London trading, the worst performing stock in the 17-member Bloomberg Europe Pharmaceutical Index, which is down 1 percent.

Benlysta was generally well-tolerated, with comparable rates of side effects and infections for patients who took the drug and those on placebo, the companies said.

The drug’s effect was measured by changes in an index of symptoms called SLEDAI, the statement said. SLEDAI scores are calculated by assigning points to symptoms including seizures, arthritis, hair loss and rash, according to the American College of Rheumatology. Investigators considered the drug worked if it resulted in at least a four-point reduction, according to the statement.

Previous Study

In a previous study, called Bliss-52, a low dose of Benlysta improved symptoms in 51.7 percent of patients, while a placebo helped 43.6 percent. A higher dose of Benlysta improved symptoms 57.6 percent.

Benlysta and an experimental drug for hepatitis C are Human Genome’s lead products. The company also is conducting late- stage studies of novel treatments for type 2 diabetes and heart disease.

The drug may bring in $15,000 to $20,000 a year per patient, based on the history of rheumatoid arthritis and multiple sclerosis treatments, said Barry Labinger, Human Genome’s chief commercial officer, on July 20.

Disease Progression

Lupus, which killed the American fiction writer Flannery O’Connor, causes extreme tiredness, headaches, painfully swollen joints, and hair loss. The disease eventually causes inflammation of organs including the heart, leading to heart disease; the liver, leading to jaundice and hepatitis; and the brain, leading to high fevers, seizures and psychosis, according to the Lupus Foundation of America, a Washington-based patient advocacy group.

“These patients haven’t had a new drug in more than 50 years,” said Thomas Watkins, Human Genome Sciences’ chief executive officer, in a telephone interview today. “We’re delighted.”

The disease has been challenging for researchers and drug developers trying to design clinical trials because patients’ symptoms vary. The illness affects different organs in the body and symptoms tend to come and go, according to the Lupus Foundation.

Lupus is most common in women ages 15 to 45 and more prevalent in blacks, Hispanics, Asians and American Indians. About 1.5 million people in the U.S. have the disease, according to the U.S. Department of Health and Human Services.

There are about 320,000 lupus patients in the U.S. who are managed by rheumatologists, the companies said. About two-thirds of those patients, or 200,000, would be candidates for the drug. It would be used by those who have stopped responding to standard therapies, the companies said in a statement on Oct. 20.

Steroids are used in lupus patients to relieve joint pain and other symptoms of the disorder.

Cytoxan, approved in 1959, is a cancer therapy that may work to suppress the immune system’s attack on the body in lupus patients. The medicine is sold generically. Imuran, an immune system suppressant developed by GlaxoSmithKline for use in kidney transplant patients, also may help lupus patients. It has been approved in generic versions since 1999.

Roche Holding AG’s Genentech unit and Biogen Idec Inc. said in March that their jointly marketed drug Rituxan failed a lupus trial. It was the second time a late-stage study of Rituxan in lupus failed.

To contact the reporter on this story: Elizabeth Lopatto in New York at elopatto@bloomberg.net.

Last Updated: November 2, 2009 16:34 EST