Bone drugs can stop after 3-5 years
MedWire News: Experts say that postmenopausal women with osteoporosis can stop taking bisphosphonates after 3-5 years of treatment.
According to the US Food and Drug Administration (FDA), continuing to take the drugs for longer does not provide any additional protection against bone fractures.
Furthermore, it may put women at increased risk of atypical femoral fractures and oesophageal cancer, recently reported as potential adverse effects of long-term bisphosphonate use.
The FDA reviewed three long-term extension trials of bisphosphonates in patients who had suffered bone fractures and/or had low bone mineral density (BMD). The trials involved nearly 2,500 patients and treatment with alendronate, risendronate or zoledronic acid continued for between 6 and 10 years, with some patients initially assigned to the intervention switching to placebo after 5 years.
Overall, continued treatment with the drugs beyond 5 years resulted in maintenance of BMD in the femoral neck and further increases in BMD in lumbar spine. Meanwhile switching to placebo led to modest reductions in BMD in the femoral neck for 1-2 years and stabilisation thereafter, and continued increases in BMD in the lumbar spine despite the discontinuation of therapy.
The pooled fracture rate was 9.3-10.6% among patients who received continuous treatment for 6 years or more, compared with 8.0-8.8% among those who switched to placebo, but the reviewers could not properly analyse the potential increased risk of fracture from prolonged treatment owing to statistical limitations.
Writing in an editorial discussing the review, Dr Marcea Whitaker and colleagues from the FDA comment: "The available data do suggest that bisphosphonates may be safely discontinued in some patients without compromising therapeutic gains, but no adequate clinical trials have yet delineated how long the drugs' benefits are maintained after cessation."
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By Caroline Price