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Once-a-year drug targets osteoporosis

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Times Staff Writer

A yearly 15-minute intravenous infusion of a new drug substantially reduces bone fractures in post-menopausal women, offering a new treatment option for women who have trouble taking existing bone-strengthening drugs, researchers reported today.

Although drugs like Fosamax and Actonel are also effective at preventing bone loss and reducing the major health risks associated with fractures, up to half of women stop taking the medications within six months because of the complicated regimen required and the risk of side effects.

The new drug, called zoledronic acid, “requires an encounter with the medical establishment only once a year, so there is no problem with compliance and adherence,” said Dr. Robert R. Recker of the Creighton University School of Medicine in Omaha.

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The drug also avoids the esophageal problems that are common with the oral drugs, said Recker, who is vice president of the National Osteoporosis Foundation and was not involved in the study.

The three-year study of 7,736 post-menopausal women found a 70% reduction in the risk of spinal fractures and a 40% reduction in the risk of hip fractures.

“But even more remarkable were the strong, significant and consistent effects across all fracture types,” said epidemiologist Dennis Black of the UC San Francisco School of Medicine, who led the study.

The results were “impressive,” wrote Dr. Juliet Compston of the University of Cambridge School of Clinical Medicine in Britain in an editorial accompanying the report in the New England Journal of Medicine.

The drug is already sold by Novartis in the United States under the brand name Zometa for the treatment of Paget’s disease -- a genetic disorder in which bone becomes soft and breaks down readily -- and the prevention of bone loss in cancer chemotherapy.

The company is applying to the Food and Drug Administration to sell it under the name Reclast for treatment of osteoporosis.

About 10 million people in the United States suffer from osteoporosis, and another 34 million have low bone density, which puts them at risk for the disorder, according to the osteoporosis foundation.

One out of every two women over 50 will suffer a fracture, many of them quite serious.

Among women over 65, for example, one out of every five who suffer a broken hip will die within a year from complications.

Reclast, Fosamax, Actonel and Boniva are all members of a class of drugs called bisphosphonates, which bind to cells in bones and prevent them from breaking down bone tissue.

This breakdown is part of the body’s normal process for remodeling bones, but in older people the breakdown tends to outrun the rebuilding, leading to a net loss of bone.

Existing drugs are given orally either weekly, monthly or every three months.

They must be taken on an empty stomach with a full glass of water and the patient must remain upright for at least 30 minutes after taking them.

“The other drugs on the market are good drugs, but we know that the vast majority of people don’t stay on them past six months,” said Dr. Felicia Cosman of the Helen Hayes Hospital in West Haverstraw, N.Y., another member of the research team.

“The real advantage is that we are going to be able to give [zoledronic acid] once a year and see benefits extend to the real world,” she said.

The primary side effects of the infusion were fever and muscle pain, which could be controlled with aspirin or ibuprofen. The side effects disappeared within three days and did not recur on subsequent infusions.

About 1.5% of the women also suffered episodes of atrial fibrillation, a form of abnormal heart rhythms, within the first two months after the infusion.

Researchers are at a loss to explain this, Cosman said, because the fibrillations have not been seen in previous trials and “we don’t understand what the potential biological mechanism is.”

In a second paper in the journal, however, Black and his colleagues found a similar risk during a reexamination of data from trials for Fosamax.

“I think it is a problem that could have occurred by chance,” Recker said. “It doesn’t disturb me much.”

The trial was sponsored by Novartis and all of the researchers have received grants or other support from pharmaceutical companies.

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thomas.maugh@latimes.com


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