New findings may pave the way for people with stage IV breast cancer in the bones to receive bone-strengthening treatment less often. These results could mean decreased risk of side effects.
Background and Goals
Bone metastases, breast cancer that spread to the bones, puts those affected by it at high risk for skeletal-related events, also known as SREs, such as broken bones, pressure on the spinal cord, or the need for radiation or surgery to the bones. Zoledronic acid (Zometa) is a bisphosphonate, a medicine that is used to treat high blood calcium and bone pain and to prevent fractures in those with bone metastases.
Zoledronic acid is FDA approved to be given as a 4 milligram infusion, or IV, every 3 to 4 weeks. The goal of the OPTIMIZE-2 trial was to determine if there is any difference in the number of SREs and other side effects observed, when zoledronic acid is given every 4 weeks versus every 12.
The OPTIMIZE-2 trial included about 400 participants, all of whom had bone metastases and had at least nine doses of zoledronic acid or pamidronate (Aredia), another bisphosphonate, in their first 10 to 15 months of therapy. Participants were randomly divided into two groups.
Over the course of 1 year, in one group
- Participants received zoledronic acid every 4 weeks
In the other group
- Participants received zoledronic acid every 12 weeks
- Placebo, an inactive substance, was given by IV on weeks 4 and 8
The study was double-blind, meaning the participants, medical staff and people who analyzed the results did not know which treatment each participant received until the trial was over.
Researchers found that the number of SREs was about the same whether zoledronic acid was given every 4 weeks or every 12, while the number of women who had to change dosage or take a treatment break because of side effects was lower in the group that received zoledronic acid less often.
In the 4 week group
- 22 percent had at least one SRE
- 10 percent needed the dose changed or to take a treatment break
In the 12 week group
- 23 percent had at least one SRE
- 5 percent needed the dose changed or to take a treatment break
Though the differences in safety were small, the data did show
- Fewer kidney problems and stopped treatment in the 12 week group
- No cases of osteonecrosis of the jaw, painful exposed bone that people taking bisphosphonates may be more likely to develop, in the 12 week group, versus two cases in the group that received treatment more often
These findings should be looked at cautiously, because of the fairly small number of participants and because a third placebo group, which would have received an inactive treatment throughout the study, was dropped during the trial.
What This Means for You
The findings of this study are likely to prompt further research that could one day result in zoledronic acid being given less frequently. If you have bone metastases, this research could mean getting the medicine less often, which may make side effects, such as kidney problems and osteonecrosis of the jaw, less likely to happen.
Talk to your doctor about this and opportunities to join future trials on zoledronic acid. Clinical trial information can be found at clinicaltrials.gov.
Hortobagyi, GN, Lipton, A, Chew, HK et al. Efficacy and safety of continued zoledronic acid every 4 weeks versus every 12 weeks in women with bone metastases from breast cancer: Results of the OPTIMIZE-2 trial. Presented at 50thAnnual Meeting of the American Society of Clinical Oncology; May 30-June 2, 2014; Chicago, IL. Abstract LBA9500^.