The bisphosphonate agent Zometa® (zoledronic acid) appears to do more than just prevent bone loss; it may actually have anti-tumor activity when combined with neoadjuvant chemotherapy for breast cancer. These results were presented at the San Antonio Breast Cancer Symposium on December 13, 2008.
Zometa is a bisphosphonate drug historically used in breast cancer to help reduce complications associated with bone metastases (cancer spread to the bone). In addition, Zometa may also reduce recurrences of hormone-positive breast cancer among premenopausal women. New research now indicates that Zometa may have a direct anti-tumor effect when combined with neoadjuvant (delivered before surgery) chemotherapy treatment in women with breast cancer.
The Adjuvant Zoledronic Acid to Reduce Recurrence (AZURE) trial includes 3,360 women with Stage II/III breast cancer and is designed to determine whether Zometa in addition to adjuvant or neoadjuvant chemotherapy improves disease outcomes. The study presented at SABCS included 205 women enrolled in the AZURE trial, 104 of whom received neoadjuvant chemotherapy and 101 of whom received Zometa plus neoadjuvant chemotherapy. The results indicated that the women who received Zometa along with chemotherapy experienced one-third more tumor shrinkage, which could mean that they were able to undergo lumpectomy rather than mastectomy.
According to the analysis, the median tumor size in the Zometa-plus-chemotherapy group was 20.5 mm compared with 30 mm in the chemotherapy group. Furthermore, the complete response rate was 10.9% in the Zometa group compared with 5.8% in the chemotherapy-alone group. Only 65.3% of patients in the Zometa group required mastectomy compared with 77.9% of patients in the chemotherapy-alone group.
The researchers concluded that Zometa may have a direct anti-tumor effect on breast cancer when combined with neoadjuvant chemotherapy. Research will likely be ongoing to evaluate the effects of Zometa in the treatment of breast cancer. If these findings are confirmed, it could change the way breast cancer is treated and result in a higher percentage of women undergoing breast-conserving surgery rather than mastectomy.
 Winter MC, Thorpe HC, Burkinshaw R, et al. The addition of zoledronic acid to neoadjuvant chemotherapy may influence pathological response – exploratory evidence for direct anti-tumor activity in breast cancer. 31st Annual San Antonio Breast Cancer Symposium. December 10-14, 2008. Abstract 5101.