No improvement in bone mineral density found with risedronate

Risedronate did not prevent bone loss in premenopausal women with breast cancer who were undergoing adjuvant chemotherapy, according to new phase-3 trial data.

Data from a trial conducted by researchers from the North Central Cancer Treatment Group (NCCTG) were available on a poster presentation at the 2008 ASCO Annual Meeting.

Patients were randomly assigned to 35 mg of risedronate weekly or placebo for one year. All patients received daily 600 mg of calcium and 400 units of vitamin D daily. Most of the chemotherapy regimens included anthracyclines, taxanes or cyclophosphamide.

The primary endpoint was change in lumbar spine bone mineral density. BMD was measured at baseline and at one year. Two-hundred sixteen women enrolled, but 170 provided BMD data at 1 year.

There was no difference in the change in BMD at the lumbar spine, the femoral neck or the total hip after one year. This was true after controlling for baseline BMD and for tamoxifen use. There was also no difference in adverse events, except for worse arthralgias and chest pain in the group that received placebo.

Hines SL, Mincey BA, Sloan JA, et al. #525. Presented at: 2008 ASCO Annual Meeting; May 30–June 3; Chicago.

In a study published in The Journal of Clinical Oncology last year, Gnant et al looked at the use of bisphosphonates over three years and found that bone density changes more dramatically in year one. However, they used zoledronic acid in the study, so that could possibly account for the difference seen in this study. Also, this is a much smaller study with only one year of follow-up. It is possible that this study is underpowered. We are still going to have to wait for a larger study in which women are randomly assigned to various bisphosphonates in the adjuvant setting, and seeing whether there are substantial effects on the bone and on recurrence.

–Doug Yee, MD

HemOnc Today Editorial Board member