(HealthDay News) — Use of zoledronic acid every 12 weeks does not result in increased risk of skeletal events compared with use every four weeks among patients with bone metastases due to breast cancer, prostate cancer, or multiple myeloma, according to a study published in the Journal of the American Medical Association.
Andrew L. Himelstein, M.D., from the Helen F. Graham Cancer Center & Research Institute in Newark, Del., and colleagues randomized 1,822 patients with metastatic breast cancer, metastatic prostate cancer, or multiple myeloma with at least one site of bone involvement to receive zoledronic acid administered intravenously every four weeks or every 12 weeks (911 each) for two years. Of the patients, 795 completed the study at two years.
The researchers found that 29.5 and 28.6 percent of patients in the zoledronic acid four-week and 12-week groups, respectively, experienced at least one skeletal-related event within two years of randomization (risk difference, −0.3 percent; P < 0.001 for noninferiority).
The proportions of skeletal-related events did not differ between the groups for patients with breast cancer, prostate cancer, or multiple myeloma. Between the treatment groups there was no significant difference in pain scores, performance status scores, incidence of jaw osteonecrosis, and kidney dysfunction. Both groups had numerically identical skeletal morbidity rates, but greater turnover was seen among patients who received zoledronic acid every 12 weeks.
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“This longer interval may be an acceptable treatment option,” the authors write.
Two authors disclosed financial ties to the pharmaceutical industry.