SAN ANTONIO (San Antonio Express-News) - Doctors used to think that once their patients developed osteoporosis, there was little they could do to stop the bone deterioration that leads to thousands of debilitating fractures each year.

But treatment advances over the past five years have reshaped the outlook both for patients and the doctors who treat them, according to an osteoporosis specialist in San Antonio.

And new drugs are on the horizon that show promise of rebuilding some of the bone lost as people age, said Dr. Michael McClung, director of the Oregon Osteoporosis Center in Portland, Ore.

"We now have very clear evidence that even in patients with a very high risk, we can make a big difference," McClung said. "In fact, those are the only patients in whom we've been able to demonstrate fracture reduction."

He was among 850 doctors in San Antonio last week for the annual meeting of the American Association of Clinical Endocrinologists.

Osteoporosis afflicts an estimated 10 million Americans, most of them women over 50. The bone-weakening disease leads to some 1.5 million fractures each year.

Of greatest concern are 300,000 hip fractures each year; half of these patients never walk again without assistance, and 20 percent die within a year of some complication.

Doctors used to focus their most aggressive efforts on preventing the onset of osteoporosis because little was known about how to treat women who had the disease.

But drugs such as bisphosphonates and reloxifene, developed in the past decade, now have been proven to reduce fracture risks for osteoporosis patients, McClung said.

"We used to think those were women who were beyond hope," he said. "But now those are the people we ought to find in treatment."

Still, those drugs work by preserving existing bone. They do little to restore bone density or improve bone integrity.

But a new class of drugs, human parathyroid hormones, shows promise of doing just that and could be on the market within a year, McClung said.

The results of the first large clinical trial, involving 1,600 women, are expected to be published shortly, he said.

"That is the most exciting thing going on in the field," he said.

Parathyroid hormone regulates calcium balance in the body. Doctors have known for two decades that the hormone could promote growth of spine and hip bones, but they faced the challenge of producing the hormone synthetically, McClung said.

Scientists conquered that challenge a few years ago, and the new drugs are about to be submitted for federal approval.

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