Amgen Fails to Win Advisory Panel Backing for Expanded Use of Cancer Drug

Amgen Inc. (AMGN), the world’s biggest biotechnology company, failed to win the backing of a U.S. advisory panel for its drug to delay tumors spreading to bones in patients with advanced prostate cancer.

The panel voted 12-1 that the risks outweighed the benefits of the drug, Xgeva. Food and Drug Administration staff questioned in a Feb. 6 report whether the ability to delay tumor growth in bones is enough to justify approval. The drug, known chemically as denosumab, didn’t extend lives in a study.

Amgen, based in Thousand Oaks, California, forecasts Xgeva sales of $3 billion to $4 billion in 2015. If the company fails to win approval to use the drug for preventing the spread of prostate cancer to the bones, the lost potential revenue would be about $1 billion, Jim Birchenough, an analyst at BMO Capital Markets in New York, said today in a note to clients.

“This isn’t a question of whether this drug works,” Wyndham Wilson, chief of the lymphoma therapeutics section at the National Institutes of Health and chairman of the panel. “It’s a question of when is the most effective time to give it.”

Amgen fell 1.6 percent to $68.06 at the close of New York trading.

Previous Approval

Xgeva was approved in November 2010 to prevent bone pain and fractures caused by bone metastases. Amgen is seeking approval in Xgeva for men who aren’t responsive to hormone treatment and whose cancer hasn’t spread to the bone yet have an increased risk based on testing, Sean Harper, Amgen senior vice president of global development and corporate chief medical officer, said in a telephone interview. The patient population is about 50,000 in the U.S., he said.

Patients who take Xgeva are at higher risk for experiencing a painful jaw condition, yet survival did not differ between the groups who took the treatment to delay deadly bone metastases and a placebo. The risk of the drug make it safer for patients to continue only taking Xgeva when tumors already have spread to their bones, Wilson said.

He also suggested that companies seeking to expand the use of a drug that treats a condition into a prophylactic for that condition conduct a study comparing the treatment’s use in both situations.

The FDA is scheduled to make a decision whether to approve Xgeva by April 26. The agency doesn’t have to follow the panel’s recommendation.

Study Results

Patients who took Xgeva experienced bone metastases 4.2 months later on average than those who took a placebo, according to a company-sponsored study published in November in The Lancet medical journal. Survival didn’t differ between the groups.

Advanced prostate cancer often spreads to the bone and is rarely curable once tumors reach the bone, according to the American Cancer Society.

Of the 1,432 patients studied, five percent developed osteonecrosis of the jaw, which can cause jaw pain, tooth infection and bone inflammation, according to the study in the Lancet. The cancer society said bone metastases are one of the most common causes of pain in people with cancer. Some patients using Xgeva experienced as much as a 7.5-month delay in developing bone metastases, Harper said.

FDA staff were also concerned the drug may “shift the pattern of metastases to non-bony areas.”

Xgeva also known as Prolia in the treatment of osteoporosis in menopausal women.

To contact the reporter on this story: Anna Edney in Washington at aedney@bloomberg.net

To contact the editor responsible for this story: Adriel Bettelheim at abettelheim@bloomberg.net

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