The first new lupus treatment in half a century moved closer to U.S. approval on Tuesday as an advisory panel endorsed a potential blockbuster medicine from Human Genome Sciences Inc.

Benlysta could offer a new option for patients with lupus, a debilitating and potentially fatal autoimmune disease that has proved difficult to treat. Annual global sales are forecast at $2.2 billion by 2014, according to Thomson Reuters.

That would transform unprofitable biotech Human Genome into an industry star.

Benlysta profits will be split with British partner GlaxoSmithKline Plc. Shares of both companies rose in after-hours trading following the positive ruling from the Food and Drug Administration advisers.

The FDA panel voted 13-2 to recommend approval of Benlysta. Supporters said the medicine helped ease symptoms with acceptable risks for a disease with limited options.

“The efficacy is mild, but I think there is a need for a drug even with mild efficacy,” said panel member Dr. Lenore Buckley, a professor of internal medicine and pediatrics at Virginia Commonwealth University.

The FDA usually follows panel recommendations when deciding whether to approve new medicines. A final FDA ruling is due by December 9.

“It was a huge victory for the company (Human Genome),” said ISI Group analyst Mark Schoenebaum. “I think the biotech community has another blockbuster drug on its hands.”

Trading in shares of Rockville, Md.-based Human Genome had been halted while the advisory panel met on Tuesday. When trading resumed after hours, its shares rose 9.7 percent to $28.40 from Monday’s $25.88 close. Glaxo’s U.S. shares climbed 2.9 percent to $39.65 in extended trading from Tuesday’s regular close at $38.54.

INVESTORS ONCE DESPAIRED

Human Genome shares have soared with hopes for Benlysta. Investors had largely written off the drug after mixed data from an earlier trial. Shares fell below 50 cents a share in March 2009 but jumped later that year after the first encouraging Benlysta data was released.

(For a graphic on how prospects for Benlysta have affected Human Genome shares, click on r.reuters.com/sed35q )

Geoffrey Porges, an analyst with Sanford Bernstein, said the drug’s approval was highly likely, although it may not come by December 9 as the companies will need to negotiate label instructions and post-approval studies with the FDA.

“You’ll be left with a product with some restrictions on who it will be used for. That will be a hook for the payors to impose some restriction,” Porges said. He sees the drug reaching the market by the end of the first quarter of 2011 and forecasts U.S. revenue of $2 billion by 2015.

Benlysta, known generically as belimumab, is given once a month by intravenous infusion. Analysts expect the drug will cost a patient between $15,000 and $30,000 annually, a price in line with biotech medicines for other autoimmune diseases.

Current treatment typically includes immunosuppressant drugs such as Roche’s CellCept and steroids such as prednisone. Hopes for effective and safer alternatives were dashed in recent years when several companies failed in attempts to develop new treatments.

Lupus causes the immune system to attack the body’s own tissue and organs. It can lead to arthritis, kidney damage, chest pain, fatigue, skin rash and other problems. Organ damage can be fatal.

An estimated 5 million people worldwide have the disease, and many cannot find relief with current drugs or suffer harsh side effects such as severe bone loss from steroids.

Patients, family members and other advocates pleaded with the panel to back Benlysta. Many spoke through tears as they described how the disease caused crushing fatigue, joint pain, and other symptoms.

TEARFUL PATIENTS

Forty-six-year-old Donna Flenory said lupus forced her to give up her career as an occupational therapist. High doses of steroids helped for a time but repeated flare-ups sent her to the hospital every year, usually in the autumn.

After joining a study of Benlysta, “when fall rolled around I was no longer sick. I had a life again,” she told the panel, adding “please realize we as patients need something.”

FDA reviewers, however, suggested Benlysta might have only a modest effect on lupus symptoms and might raise the risk of death, infection, or psychiatric problems including suicide. Two patients treated with Benlysta during clinical trials killed themselves and there were no suicides with a placebo.

Panel members said there were too few suicides and other deaths to conclude Benlysta was the cause but urged monitoring of side effects if the drug reached the market.

The drug’s safety “looks remarkably good compared to a lot of other drugs we’re using,” said panel member R. John Looney, a rheumatologist at the University of Rochester.

Benlysta is designed to inhibit BLyS, a protein in the body that exists to keep B-cells functioning normally. B-cells make antibodies that prevent infection. In lupus patients, B-cells are overstimulated and make antibodies that attack the body.

Human Genome Chief Executive Thomas Watkins, speaking to reporters after the panel meeting, said the company was pleased with the ruling. “We will look forward to working with the FDA as they complete their work,” he said.

An application for approval also is pending in Europe, he said.

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By Lisa Richwine

ADELPHI, Maryland