MedicalResearch.com Interview with:
Gabriel N. Hortobagyi, MD, FACP, FASCO
Professor, Department of Breast Medical Oncology
Division of Cancer Medicine
The University of Texas MD Anderson Cancer Center
Houston, TX 77230-1439
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Bisphosphonates have been commercially available for several decades as supportive care for patients with bone metastases. They reduce the frequency and severity of bone-related complications. While the optimal dose and short-term scheduling of zoledronic acid (and previously, pamidronate) have been determined, there has been no research to determine how long these drugs need to be maintained nor the optimal dose and schedule beyond the first year of therapy. These questions are particularly important for this family of drugs, since they are incorporated into bone and not excreted from the body for many years.
We set out to determine whether a reduction in the frequency of administration of zoledronic acid (every 12 weeks) was able to maintain the therapeutic efficacy of this intervention when compared to the “standard” schedule of administration (every 4 weeks). It was a prospective, randomized, non-inferiority trial that recruited patients with metastatic breast cancer with bone metastases and who had previously received 9 or more doses of zoledronic acid or pamidronate. The primary endpoint was the proportion of patients with one or more skeletal-related events. Four hundred and sixteen patients were randomized in a 1:1 ratio. The two groups were comparable at baseline. After the first year of follow-up, there was no statistically significant difference in SRE rate between the two arms, confirming the non-inferiority fo the every-12-week schedule of zoledronic acid.
MedicalResearch.com: What should readers take away from your report?
Response: After one year of monthly administration of an intravenous bisphosphonate, bisphosphonate therapy can continue at a lower frequency without reduction in therapeutic efficacy during the second year.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Additional research is needed to determine whether the lower frequency of administration is equivalent in subsequent years and to determine what is the optimal duration of administration of bisphosphonates in patients with metastatic bone disease. These questions are important, since in the breast cancer area, some patients with bone metastases live for 5-10 years after developing metastatic disease. Chronic administration of bisphosphonates has been associated with increased risk of rare complications, such as osteonecrosis of the jaw, atypical fractures of long bones and renal dysfunction.
MedicalResearch.com: Is there anything else you would like to add?
Response: I received research funding from Novartis to perform this clinical trial.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Hortobagyi GN, Van Poznak C, Harker WG, Gradishar WJ, Chew H, Dakhil SR, Haley BB, Sauter N, Mohanlal R, Zheng M, Lipton A. Continued Treatment Effect of Zoledronic Acid Dosing Every 12 vs 4 Weeks in Women With Breast Cancer Metastatic to BoneThe OPTIMIZE-2 Randomized Clinical Trial. JAMA Oncol. Published online January 26, 2017. doi:10.1001/jamaoncol.2016.6316
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