 |
 |
 |
 |
|
Update on OsteoporosisNew treatments promise to rebuild bone faster, reduce pain
At least 10 million Americans (mostly older women) suffer from osteoporosis, and another 28 million have thinning bones (osteopenia), which puts them at high risk of fractures. A major risk factor is the decline in estrogen after menopause; estrogen replacement was once considered the only way to stem bone loss. That changed more than a decade ago with the approval of drugs called bisphosphonates, which slow the breakdown of bone.
Newer treatments are now in the pipeline, including an injectable drug that promises to build bone faster than bisphosphonates, and an experimental procedure to relieve pain caused by spinal fractures.
Parathyroid hormone
The new drug is a version of parathyroid hormone, normally secreted by tiny glands in the neck. A multi-national clinical trial showed that it dramatically reduces the risk of fractures in women with osteoporosis.
The trial was conducted among 1,637 postmenopausal women in almost a dozen countries, including the U.S. The women, who had suffered at least one fracture, were assigned to either 20 or 40 micrograms (mcg) of the drug, teriparatide (Forteo), or to dummy injections. After 18 months of treatment, women on the higher dose of Forteo had 13% more bone in their spine than women taking placebo. Forteo reduced new spinal fractures by 65 to 69%, depending on the dose. The study appeared in the May 10, 2001 New England Journal of Medicine.
Bisphosphonates, like alendronate (Fosamax), slow the resorption of bone; Forteo helps the body build more bone. Forteo has not yet been compared with bisphosphonates. Alendronate and similar drugs increase BMD by about 9%, and reduce new fractures by 40% to 50%. The manufacturer hopes for FDA approval of Forteo by year’s end.
Easier dosing, fewer side effects
While alendronate slows the breakdown of bone, it can also cause gastric side effects, including irritation of the esophagus.
Alendronate must be taken with six to eight ounces of water, first thing in the morning on an empty stomach (and the patient cannot not lie down or take other medication for 30 minutes). An easier-to-take, once-a-week dose (35 or 70 milligrams) is now available. A one-year study among 1,258 women aged 40 to 90, found the 70 mg weekly dose increased BMD in the hip and spine by around the same amount as daily (10 mg) and twice weekly (35 mg) doses, with less gastric irritation.
The effects of alendronate are lasting. Studies among three groups of women treated with different doses of daily alendronate over a seven-year period showed that BMD continued to rise during each year of active treatment. “Surprisingly—and in contrast to other anti-resorptive agents—those women who took alendronate for five years and placebo for the last two years did not have the accelerated rate of bone loss accompanied by a rapid rise in markers of bone resorption, as we see when estrogen replacement therapy is discontinued,” remarked James A. Simon, MD, clinical professor at George Washington University and director of research at the Osteoporosis Diagnostic and Monitoring Center of Laurel, Maryland.
Bisphosphonates best after 60?
Bisphosphonates may be the preferred treatment for older women. A review of 22 studies in the June 13, 2001 Journal of the American Medical Association (JAMA), found that hormone replacement therapy (HRT) lowered the risk of non-vertebral fractures by up to 50%, but the effects appeared to be greater for women in their late 40s or 50s. The review found no significant fracture reduction benefits for HRT when it was started after age 60, and concluded that bisphosphonates are more effective among older women.
Other new therapies
Future treatments may combine bone-building and anti-resorptive agents.
Preliminary studies show parathyroid hormone may be most effective when used with drugs like alendronate. “A small study published last year, among 66 postmenopausal women aged 50 to 79 with osteoporosis, given injections of a parathyroid hormone for a year, followed by daily doses of alendronate, showed up to a 14% increase in bone mineral density,” Dr. Simon told the 9th annual Congress on Women’s Health in June. “This is the equivalent of taking someone who has a fracture and osteoporosis and, in the span of two, three or four years, bringing them from a very abnormal bone density into the normal range.”
Other treatment options include the SERM (selective estrogen receptor modulator) raloxifene (Evista), and a newer bisphosphonate, risedronate (Actonel). Studies show Evista slightly raises BMD and lowers fracture risk. A recent study found Actonel reduces the incidence of spine fractures by up 60% and, in combination with HRT, increases BMD by more than 5%.
A recent analysis of eight observational studies shows that the cholesterol-lowering drugs called statins may also protect against fractures.
And a therapy long used in Europe, tibolone (Livial), a synthetic hormone made from soybeans and yams that has estrogenic effects, is now in clinical trials here. A soon-to-be published study found that tibolone increased BMD in the hip and spine by almost 3% over two years, while women on placebo lost bone, said Dr. Simon.
New help for spinal fractures
As many as 700,000 people a year suffer vertebral (spinal) fractures, usually as a result of osteoporosis. These “compression” fractures occur when the weakened spinal vertebrae collapse, typically in the mid or lower back. Sitting or standing further compresses the broken vertebra, causing excruciating pain. Women often suffer a series of fractures, causing a “widow’s hump” (thoracic kyphosis), leading to height loss and digestion and breathing problems.
A new procedure called vertebroplasty infuses special cement into the spine to stabilize collapsed or crushed vertebrae, reducing back pain. Imaging equipment is used to guide a hollow needle about the size of a cocktail straw into the crushed vertebra under local anesthetic. Bone cement is then injected, stabilizing the bone to prevent further collapse.
According to the Society of Cardiovascular and Interventional Radiology (SCVIR), most patients report their pain is gone or significantly better within 48 hours. The procedure has only been used a short time in the U.S. specifically for spinal fractures, but has been performed for more than a decade in France.
A second, still-experimental treatment, called kyphoplasty, can restore lost height. First, a catheter-tipped balloon is threaded into the cracked vertebra, inflated with liquid to jack up the collapsed bone, and then bone cement is injected, restoring some height.
Both procedures are promising, but much more data is needed to prove their effectiveness, cautions Dr. Simon. These treatments do not prevent further fractures. So standard osteoporosis treatment—calcium, exercise, and medication if needed—must be continued.
This article originally appeared in the August 2001 issue of Women's Health Advisor.
