Ibandronate in Early Breast Cancer Does Not Improve Outcomes

The bisphosphonate ibandronate does not improve outcomes when used in early breast cancer, according to results recently published in the Journal of Clinical Oncology.

The bones are a common site to which advanced, or metastatic, breast cancer spreads in the body. Agents referred to as bisphosphonates are commonly used in metastatic breast cancer, as they have demonstrated the ability to prevent adverse effects of the cancer spread to the bone. Bisphosphonates are also commonly used for women with osteoporosis or ostopenia as they tend to reduce further bone loss and may even build the density of bones.

Although bisphosphonates have demonstrated improvements in terms of skeletal-related events among patients with metastatic breast cancer, it remains unclear if their use in early breast cancer might also confer advantageous outcomes.

To further explore the possibility of bisphosphonates’ potential outcomes among women with early breast cancer (cancer has not spread outside the breast), researchers from Germany recently conducted a phase III clinical trial, referred to as the GAIN (German Adjuvant Intergroup Node-Positive) study. The study included 2,460 patients who underwent standard dose-dense therapy for early breast cancer and were considered to be at a high risk of developing a recurrence. One group also received ibandronate with their therapy, and the other group did not receive ibandronate with their therapy.

There was no improvement in overall survival or cancer-free survival among women treated with ibandronate, compared to those who did not receive ibandronate.
Cancer-free survival tended to be improved, however, this improval tended to be among women 40 years and younger or 65 years and older. The overall cancer-free survival did not reach statistical significance (meaning it could have happened by chance)
The researchers concluded that “Adjuvant treatment with oral ibandronate did not improve outcome of patients with high-risk early breast cancer who received dose-dense chemotherapy.”

Reference: von Minckwitz G, Mobus V, Schneeweiss A, et al. German adjuvant intergroup node-positive study: a phase III trial to compare oral ibandronate versus observation in patients with high-risk early breast cancer. Journal of Clinical Oncology. Published online August 26, 2013. doi:10.1200/JCO.2012.47.2167.