Ixempra™ plus Xeloda® Improves Progression-free Survival in Triple-negative Metastatic Breast Cancer
The combination of Ixempra® (ixabepilone) and Xeloda® (capecitabine) significantly increases progression-free survival in women with triple-negative metastatic breast cancer, according to the results of a study presented at the San Antonio Breast Cancer Symposium on December 12, 2008.
Some breast cancers display different characteristics that require different types of treatment. The majority of breast cancers are hormone receptor-positive breast cancers, meaning that the cancer cells are stimulated to grow from exposure to the female hormones estrogen and/or progesterone. These cancers are typically treated with hormone therapy to prevent or reduce these hormones, thereby preventing the growth of cancer cells. Other cancers are referred to as HER2-positive, which means that they overexpress the human epidermal growth factor receptor 2, a biologic pathway that is involved in replication and growth of a cell. HER2-positive breast cancers account for approximately 25% of breast cancers and are treated with agents that target the receptor to slow growth and replication.
Breast cancers that are not stimulated to grow from exposure to estrogen or progesterone and are HER2-negative are called triple-negative breast cancers. Triple-negative breast cancers tend to be more aggressive than other breast cancers and have fewer treatment options.
Standard therapy for triple-negative metastatic breast cancers typically includes chemotherapy utilizing agents in the anthracycline and taxane classes. Anthracyclines include agents such as Adriamycin® (doxorubicin), Ellence® (epirubicin), and Doxil® (pegylated liposomal doxorubicin). Taxanes include agents such as Taxol® (paclitaxel) and Taxotere® (docetaxel).
Ixempra is a chemotherapy agent that prevents or reduces cancer cells from replicating. It is approved for the treatment of advanced breast cancer.
In a pooled analysis of patients from two large Phase III clinical trials, researchers evaluated the combination of Ixempra and Xeloda versus Xeloda alone for the treatment of metastatic breast cancer. The two studies included nearly 2,000 women with metastatic breast cancer who had previously been treated with anthracyclines and taxanes. The women were randomized to receive Ixempra plus Xeloda or Xeloda alone. A pooled subset of 443 women from both studies had triple-negative disease.
The analysis of the triple-negative subset indicated that patients who received Ixempra and Xeloda had an overall response rate of 31% compared with 15% for those who received Xeloda alone. Furthermore, the group that received the Ixempra/Xeloda combination had a progression-free survival rate of 4.2 months compared with 1.7 months for those who received Xeloda alone. These results were statistically significant.
The researchers noted that Ixempra plus Xeloda is the first combination to show a statistically significant improvement in progression-free survival in patients with advanced triple-negative breast cancer. Research will likely be ongoing to further evaluate this drug combination in this population of patients.
 Rugo HS, Roche H, Thomas E, et al. Ixabepilone plus capecitabine vs capecitabine in patients with triple negative tumors: A pooled analysis of patients from two large phase III clinical studies. 31st Annual San Antonio Breast Cancer Symposium. December 10-14, 2008. Abstract 3057.