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May 9, 2007

Use of Alendronate After 5 Years of Treatment—Reply

Author Affiliations

Letters Section Editor: Robert M. Golub, MD, Senior Editor.

JAMA. 2007;297(18):1979-1981. doi:10.1001/jama.297.18.1980

In Reply: In response to Drs Erviti and Gorricho, FLEX was designed to compare continuing or discontinuing alendronate after 5 years. The study did not include a long-term placebo group because it was no longer ethical to continue placebo. This lack of a comparison group with no exposure to alendronate is a limitation of our study for both efficacy and safety analyses. One of the hypothesized safety concerns with long-term bisphosphonate use is that prolonged bone turnover suppression might decrease bone strength. We believe that this is unlikely given our fracture results, the initial FIT results showing fracture reductions with alendronate vs placebo over 4 years,1-3 and nonvertebral fracture rates in FLEX being consistent with projected rates from the FIT alendronate group. Also, the histomorphometry substudy, while very small, was consistent with normal bone remodeling.