WEDNESDAY, May 2, 2007 (HealthDay News) -- Annual injections of a common osteoporosis drug greatly reduced older women's risk for fractures, researchers report.
The findings, published in the May 3 issue of the New England Journal of Medicine, could open the door to U.S. Food and Drug Administration approval of once-a-year zoledronic acid.
"We've been waiting for this for a long time. This is really exciting stuff," said Paul Brandt, an assistant professor of neuroscience and experimental therapeutics at Texas A&M Health Science Center College of Medicine in College Station.
"Here we've got something we can give to patients when they're in the clinic with a 15-minute IV, and it lasts for a whole year," said Brandt, who was not involved in the study. "The FDA hasn't approved it for a single-year injection, but I hope it will. It sure is going to be a good kick in the right direction."
"This is a very attractive alternative for a significant number of people who cannot or will not take traditional antiresorbtive medication," said Dr. Steven R. Goldstein, a professor of obstetrics and gynecology at New York University School of Medicine and author of The Estrogen Alternative and Could It Be Menopause.... "But this is not for everybody. This study was in older people, so in a select group of patients this would be a very nice alternative but it's not going to be a sea change, nor should younger people be running towards this methodology."
The new study was funded by the drug's maker, Novartis Pharma. One outside expert agreed the new drug formulation could change the way people care for their bones.
Many women already take bone-preserving pills called oral bisphosphonates, but they're not for everyone, explained Dr. Nanette Santoro, director of the division of reproductive endocrinology in the department of obstetrics and gynecology and women's health at Montefiore Medical Center in New York City.
"For now, women who do not tolerate oral bisphosphonates well but who are good candidates will be able to take the medication in a relatively convenient form," Santoro said. "For the future, this may be a harbinger of how this class of medication will be given years from now."
Osteoporosis primarily affects women in their postmenopausal years, although it can afflict men as well. As bones thin and become more fragile, they break more easily, causing severe disability and even death.
Bisphosphonates, a class of drugs that includes zoledronic acid, are the most commonly used treatment for osteoporosis. They work by slowing the body's natural reabsorption of bone.
But there has been one enduring problem with bisphosphonates: patients don't take the drugs as they should.
"The big concern has been in patient compliance," Brandt confirmed. "The monthly pills run into problems where women start to forget. It's also a pain to take these drugs. You have to sit upright and there's a risk of acid reflux, esophageal damage."
Women also have to take the pills with a full glass of water while fasting.
According to background information in the paper, most women appear to be taking less than 80 percent of their prescribed pills by 12 months.
Previous research had shown that one annual injection of zoledronic acid improved bone density for at least one year in postmenopausal women with osteoporosis.
The current study looks at how well annual injections do three years out.
Almost 4,000 postmenopausal women were randomly assigned to receive a single 15-minute infusion of zoledronic acid or a placebo at baseline, and then 12 months and 24 months later. Participants were followed out to the 36-month point.
Treatment with zoledronic acid reduced the risk of vertebral fractures by 70 percent (3.3 percent of women in the treatment arm and 10.9 percent of women in the placebo arm suffered such fractures) over three years, the team reported. It also reduced the risk of hip fracture by 41 percent (1.4 percent of women in the zoledronic acid group vs. 2.5 percent in the placebo arm).
Meanwhile, nonvertebral fractures, clinical fractures and clinical vertebral fractures were reduced by 25 percent, 33 percent and 77 percent, respectively.
Women in the treatment arm also experienced significant improvement in bone mineral density and bone metabolism markers.
There was a slight downside to the injections: women in the zoledronic acid group experienced more incidents of an irregular heart rhythm called atrial fibrillation. Other side effects were similar in both groups, the team said.
More information
There's more on osteoporosis at the National Osteoporosis Foundation.
