Zoledronic acid receipt every 12 weeks may be non-inferior to infusion every 4 weeks for patients with bone-metastatic breast cancer, according to a study published in JAMA Oncology.1

Infusion of zoledronic acid, a bisphosphonate, is recommended for patients with bone metastases from solid and hematologic cancers to reduce the frequency of skeletal-related events (SREs). There is, however, a paucity of data about the efficacy and safety of this treatment for patients with breast cancer, who can live with bone metastases for longer than 1 year. One concern is whether frequent administration over a long period will result in accumulation of the drug within the bone.

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For this randomized trial (ClinicalTrials.gov Identifier: NCT00320710), researchers evaluated the safety and efficacy of a second year of zoledronic acid treatment. Of 416 patients enrolled, 200 patients were assigned to treatment every 4 weeks, 203 were assigned to treatment every 12 weeks, and 13 were assigned to placebo. The placebo arm was, however, eliminated after the approval of bisphosphonates.

Twenty-two percent of patients in the 4-week group had at least 1 SRE vs 23% in the 12-week group. There was no significant difference in SRE-free survival.

In both groups, 189 patients had at least 1 adverse event. Among common adverse events, fatigue was more common in the 12-week group, while arthralgia, nausea, and back pain were more common in the 4-week group.

RELATED: Bone-metastatic Cancer: Zoledronic Acid and Skeletal Events

The authors concluded that 12-week administration of zoledronic acid is non-inferior to 4-week administration among patients with breast cancer who complete at least 9 doses of bisphosphonate treatment.


  1. Hortobagyi GN, Van Poznak C, Harker WG, et al. Continued treatment effect of zoledronic acid dosing every 12 vs 4 weeks in women with breast cancer metastatic to bone: the OPTIMIZE-2 Randomized Clinical Trial. JAMA Oncol. 2017 Jan 26. doi: 10.1001/jamaoncol.2016.6316 [Epub ahead of print]