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« on: May 11, 2007, 06:48:03 pm » |
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May 2, 2007 — Once-yearly infusion of zoledronic acid effectively reduces the risk for vertebral and hip fractures during a 3-year period, according to the results of a double-blind, placebo-controlled, randomized study of postmenopausal women published in the May 3 issue of The New England Journal of Medicine.
"A single infusion of intravenous zoledronic acid decreases bone turnover and improves bone density at 12 months in postmenopausal women with osteoporosis," write Dennis M. Black, PhD, from the University of California in San Francisco, and colleagues from the HORIZON (Health Outcomes and Reduced Incidence With Zoledronic Acid Once Yearly) Pivotal Fracture Trial. "We assessed the effects of annual infusions of zoledronic acid on fracture risk during a 3-year period."
In the current study, 3889 women were randomized to receive a single 15-minute infusion of zoledronic acid (5 mg), and 3876 were randomized to receive placebo at baseline, 12 months, and 24 months. Mean age was 73 years, and follow-up was until 36 months. The primary outcomes were new vertebral fracture in patients not taking concomitant osteoporosis medications and hip fracture in all patients; secondary outcomes were bone mineral density (BMD), bone turnover markers, and safety outcomes.
During a 3-year period, zoledronic acid treatment was associated with 70% reduction in risk for morphometric vertebral fracture vs placebo (3.3% in the zoledronic acid group vs 10.9% in the placebo group; relative risk [RR], 0.30; 95% confidence interval [CI], 0.24 - 0.38). Reduction in risk for hip fracture was 41% (1.4% in the zoledronic acid group vs 2.5% in the placebo group; hazard ratio, 0.59; 95% CI, 0.42 - 0.83). Reduction in risk for nonvertebral fractures, clinical fractures, and clinical vertebral fractures was 25%, 33%, and 77%, respectively (P < .001 for all).
Zoledronic acid was also associated with a significant improvement in BMD and bone metabolism markers. Although adverse events, including change in renal function, were similar in the 2 study groups, serious atrial fibrillation occurred more frequently in the zoledronic acid group (50 vs 20 patients; P < .001).
"A once-yearly infusion of zoledronic acid during a 3-year period significantly reduced the risk of vertebral, hip, and other fractures," the authors write. "In addition, the treatment had a favorable safety profile and was generally well tolerated. Given the relatively poor adherence to oral bisphosphonate therapy in clinical practice, annual infusion of zoledronic acid may provide a promising approach to reducing fracture risk."
Novartis Pharma, the maker of zoledronic acid, supported this study. Some of the authors have disclosed various financial relationships with Novartis, Merck, Amgen, Eli Lilly, GlaxoSmithKline, and other pharmaceutical companies and organizations. A complete listing of financial relationships is available in the original article.
N Engl J Med. 2007;356:1809-1822.
Source: http://www.medscape.com/viewarticle/555932?src=mp
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