Intermittent infusions of the biophosphate zoledronic acid in postmenopausal women--with dosages as far apart as 12 months--increase bone density and decrease markers of bone resorption as effectively as daily oral biophosphate therapy without significant side effects, Dr. Ian R. Reid of the University of Auckland, New Zealand, and his colleagues reported.
The 1-year, randomized, placebo-controlled study of 351 women with mild bone density loss, defined as a T score of less than -2, suggested that an annual infusion of the drug could control osteoporosis and eliminate the adverse effects of oral therapy that often decrease patient compliance, the investigators said (N. Engl. J. Med. 346:653-61, 2002).
Novartis, which markets zoledronic acid as Zometa for the treatment of cancer-related bone metastases, designed and funded the study managed the data, and performed the statistical analysis.
The women received one of six treatment regimens during the study: zoledronic acid infusions every 3 months at dosages of 0.25 mg, 0.05 mg, or 1 mg; a 2-mg infusion every 6 months; a single 4-mg infusion; or a saline placebo.
At 12 months, bone mineral density at the spine in all the active treatment groups was 4.3%-5.1% higher than in the control group; bone mineral density at the femoral neck was 3.1%-3.5% higher than in the control group.
In the active treatment groups, bone resorption markers reached a nadir at 1 month and remained suppressed for the entire study, even with the single-dosage regimen. The control group had no significant marker changes.
Five nonvertebral fractures occurred in the active treatment groups, but the investigators said that a larger study would be necessary to determine the long-term effects of infusion therapy on fractures. Up to 67 percent of the active groups reported mild nausea, myalgia, and fever, most often after the first dosage.
COPYRIGHT 2002 International Medical News Group
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