Breast Cancer Coverage from Every Angle

De-escalation of Bone-Targeting Agents for Bone Metastases From Breast Cancer

By: Kayci Reyer
Posted: Tuesday, July 16, 2019

Research presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 11501) found no significant difference in outcomes between patients receiving bone-targeted agents every 4 weeks versus every 12 weeks. The study included patients with breast cancer and patients with castration-resistant prostate cancer, all of whom had bone metastases.

“The data presented would suggest that de-escalation of all commonly used [bone-targeting agents] is a reasonable treatment option,” concluded Mark J. Clemons, MD, of the University of Ottawa in Canada, and colleagues.

A total of 263 patients (60.8% with breast cancer, 39.2% with prostate cancer) were randomly assigned to receive either 12-weekly (n = 130; 49.4%) or 4-weekly (n = 133; 50.6%) bone-targeting agent therapy. The agents administered included denosumab (n = 148; 56.3%), zoledronate (n = 63; 24.0%), and pamidronate (n = 52; 19.8%). The majority of participants (n = 138; 52.5%) had not previously received bone-targeted agents.

The researchers did not find a meaningful difference in outcomes between the 12-weekly and 4-weekly groups. The median measurements in health-related quality of life (0 with 12-weekly vs. 0 with 4-weekly), pain (0 vs. 0), Global Health Status (0 vs. 0), symptomatic skeletal events rates (18.5% vs.16.5%), and 1-year symptomatic skeletal event–free rate (73.2% vs. 77.9%) were similar in both groups. In addition, there were no significant differences in outcomes found in patients who had received and those who had received prior bone-targeted agents, nor were there differences in outcomes among those receiving denosumab versus zoledronate versus pamidronate. This finding extended to comparable reports of renal impairment (2.3% with 12-weekly vs. 3.0% with 4-weekly), symptomatic hypocalcemia (1.5% vs. 1.5%), or osteonecrosis of the jaw (0.8% vs. 0.8%).

Disclosure: The study authors’ disclosure information may be found at

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