Drug Therapies Combat Advanced Osteoporosis

New research is trying to find the most effective drug combinations for people with advanced osteoporosis. One study found that delivering parathyroid hormone on three-month cycles may be a more efficient way to strengthen bone quality.

A second study found that gains in bone density achieved after taking parathyroid hormone are lost if that regimen is not followed by alendronate -- or Fosamax, a bisphosphonate.

Both studies looked at people with severe cases of the disease and are published in the Aug. 11 issue of the New England Journal of Medicine.

"This combination of two very expensive drugs is trying to fine-tune the best therapy for people who already have severe osteoporosis and are at the end of the road," said Dr. Steven R. Goldstein, professor of obstetrics and gynecology at New York University School of Medicine in New York City. "The more important aspect of bone health for me and for most physicians is in preventing our patients from getting to the point where they might be candidates for this kind of therapy."

According to an accompanying editorial in the journal, five drugs have been approved for the treatment or prevention of osteoporosis in the United States in the last decade. The drugs fall into two main categories: those that reduce bone remodeling (such as alendronate) and those that stimulate bone formation (such as parathyroid hormone).

While each class has been shown to reduce the risk of fractures, it has been unclear how they work together.

The authors of the first study sought to discover whether parathyroid hormone would work just as well on women who have been on other therapies and whether cyclic (as opposed to daily) therapy was more effective for bone formation.

One hundred twenty-six women with severe osteoporosis who had been taking alendronate for an average of three or more years were randomly assigned either to continue alendronate alone, to take alendronate plus parathyroid hormone daily or to take the combination in three-month cycles.

"We saw better maintenance of bone formation effect with repeated cycles," said Dr. Felicia Cosman, lead author of the study, and osteoporosis specialist and director of the clinical research center at Helen Hayes Hospital in West Haverstraw, New York.

"It does look like cyclic therapy is a rational approach but we need to test it further at this point. If further testing confirms the findings, this means that with less patient effort and better tolerability, we may be able to get a better effect," added Cosman, an associate professor of medicine at Columbia University in New York City.

The study also confirmed that, even with patients who have been on alendronate long-term, parathyroid hormone works. X-ray data suggested that parathyroid hormone may reduce the risk of further vertebral fractures but the results were not statistically significant. "It's suggestive that maybe the increase in bone density is associated with expected improvements in bone strength and bone fractures," Cosman said.

Along similar lines, the second study found that alendronate therapy given after parathyroid hormone therapy led to significant increases in bone mineral density. When alendronate was not given, increases in bone density were rapidly lost.

The editorial, however, stressed that the results of both trials were preliminary.

And other experts stressed that the key to osteoporosis is to start treating people at earlier stages of disease, or perhaps even before they've developed the disease.

"These are people way at the end of the line, who come into the care of bone specialists," Goldstein said. "The relevance of such a study to the overwhelming majority of women at risk for future fragility fractures is low. Every day, we're trying to prevent women from getting to the point where they would possibly think about such a combination of two such potent and expensive drugs."

By Amanda Gardner
HealthDay Reporter (8-10-2005)

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