Addition of Avastin® to Taxotere® Improves Progression-free Survival in Advanced Breast Cancer
Women with advanced HER2-negative breast cancer who were treated with Avastin® (bevacizumab) in addition to Taxotere® (docetaxel) experienced longer progression-free survival than those treated with Taxotere alone. Furthermore, higher doses of Avastin resulted in greater improvements to progression-free survival. These results were recently reported at the 2008 annual meeting of the American Society of Clinical Oncology.
Advanced (metastatic) breast cancer refers to cancer that has spread to distant sites in the body. Chemotherapy is a cornerstone of therapy for metastatic breast cancer; however, novel therapeutic approaches are now providing more targeted methods of treatment. Because breast cancer cannot be cured in the majority of patients, a major goal of therapy is to keep the cancer from progressing while maintaining quality of life.
The HER2 pathway is a biological pathway within cells that is involved in cellular replication and growth. Approximately 25–30% of breast cancers overexpress the HER2 protein on the surface of the cell; these cancers are referred to as HER2-positive breast cancers. HER2-negative breast cancers, on the other hand, do not have an overabundance or mutation of HER2. The distinction between HER2-positive and HER2-negative disease is critical in treatment planning, as agents targeted against the HER2 pathway are ineffective in HER2-negative breast cancer. Effective treatments for HER2-negative disease must therefore target other areas of the cancer, such as the protein known as vascular endothelial growth factor (VEGF).
Avastin is a targeted therapy that blocks VEGF. VEGF stimulates the growth of new blood vessels. Avastin is already approved for the treatment of some colorectal and lung cancers.
A multinational Phase III clinical trial was conducted to evaluate the addition of Avastin to Taxotere. The study included 736 patients with advanced HER2-negative breast cancer who had not received prior therapy for metastatic disease. All patients were treated with Taxotere. Patients were then divided into two groups: one group received Avastin until disease progression, while the other group received placebo (inactive substitute). Patients treated with Avastin received either a lower or higher dose of the drug. Median follow-up was approximately one year.
- Progression-free survival was improved by 30–40% among patients treated with Avastin/Taxotere compared with Taxotere alone.
- Survival was improved even more among patients who received higher doses of Avastin (32% improvement versus 8% for the lower-dose group).
- No significant side effects were reported.
The researchers concluded that the addition of Avastin to Taxotere improves progression-free survival in advanced HER2-negative breast cancer and that survival is further improved with higher doses of Avastin. Patients diagnosed with this form of breast cancer may wish to discuss with their physician the risks and benefits of treatment with Avastin and Taxotere.
Reference: Miles D, et al. Randomized, double-blind, placebo-controlled Phase III study of bevacizumab (BV) with docetaxel (D) or docetaxel with placebo (PL) as first-line therapy for patients wit locally recurrent or metastatic breast cancer (mBC): AVADO. ASCO Meeting 2008; Abstract LBA1011.