March 10, 2000

Investigators probe new drug’s ability to boost bone density

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Nuclear Medicine Technologist Chris Smith administers a bone-density screen to patient Judy Bloeser. (photo by Dana Johnson)

Investigators probe new drug's ability to boost bone density

Vanderbilt University Medical Center researchers are investigating a new drug's ability to increase bone density in patients with osteoporosis.

VUMC is one of 60 centers around the world taking part in a long-term clinical study of the new drug, which is seeking women over the age of 65 who have undiagnosed osteoporosis. The plan is to treat them before brittle bone problems develop.

"We want to have an opportunity to see if they have it and then see if they respond to treatment," said Dr. S. Bobo Tanner IV, assistant professor of Medicine, medical director of Vanderbilt's Asthma, Sinus and Allergy Program and principal investigator for this rheumatology study.

Osteoporosis is a disease in which bones become thin and weak. It occurs mostly in post-menopausal women because the female hormone estrogen — which helps maintain bone strength — declines at this time. As bones weaken, they break more easily.

Tanner says that nearly 50 percent of women over the age of 60 who have gone through menopause have some evidence of thin bones. He calls osteoporosis the silent disease.

"You don't necessarily hurt or have any symptoms until you have actually had a fracture. In order to get people aware of the fact that they are at risk for fractures, you have to find who has low bone density," Tanner said.

"Then we treat them before they have that first fracture and work to prevent any subsequent problems."

Once identified through a painless Bone Mineral Density Test and admitted into the study, participants will be given a new anti-resorptive drug for increasing bone density and reducing fracture risk.

Participants will be followed for up to two years. It is very important in this study, Tanner said, to promote the use of the medication long-range.

"The reinforcement issue is something that hasn't always been used in a long-term trial. Sometimes people don't take their medicine as regularly, so being able to reinforce that by monitoring progress and providing feedback is the kind of thing we are looking for."

The drug under investigation is no replacement, however, for that old standby of healthy bones: calcium.

"Calcium is the bricks and mortar of strong bones, so even osteoporosis medications require adequate calcium in order to make bone and maintain good bone density," Tanner said.

"Bone is a dynamic organ. It changes all the time. Not only if you break a bone does it repair itself, but as you change stress on the bone, it remodels itself and changes its density.

"It's also a source of calcium for other functions in your body. If your muscles or blood are low on calcium, they will go and rob it out of your bone in order to maintain body functions."

There were 1.5 million fractures from osteoporosis reported last year in this country, according to Tanner. There were more osteoporotic fractures in women last year than there were heart attacks, strokes, breast cancer and uterine cancer cases combined, Tanner said.

And some of those fractures are not easy to recover from.

"It is hard for somebody over 60 to completely recover from a broken hip. Perhaps 40 percent of these folks end up in wheelchairs or require walking canes or even end up in nursing homes because they are no longer independent," Tanner said.

"Actually a hip fracture can lead to an early death. After a fracture, patients can develop blood clots in the lungs, pneumonia, or experience a general decline in health from being less active."

So far, Tanner has enrolled only one woman in the study. He expects to screen about 50 women to get the 10 needed to complete VUMC's portion.

"I want to encourage people to be willing to sign up for these types of studies because it is very important, not only for their own health, but for others like them," Tanner said. "The FDA uses the data from these studies to determine whether a medication is effective and for whom it's most appropriate, so we need people to participate."

For more information on the study, call the Asthma Sinus Allergy Program at 936-5764.