A small, very early study found that 14 of 18 women diagnosed with metastatic, HER2-positive breast cancer got some benefit from a combination of Herceptin (chemical name: trastuzumab), Avastin (chemical name: bevacizumab), and Taxotere (chemical name: docetaxel) as a first treatment. Herceptin and Avastin are targeted therapies and Taxotere is a chemotherapy medicine. The results were presented at the 2010 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium.
Metastatic breast cancer is cancer that has spread outside the breast to another part of the body. Metastatic breast cancer is considered advanced-stage cancer. HER2-positive cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that tell the cancer to grow and spread. About one out of every four breast cancers is HER2-positive.
Herceptin, given intravenously, works by attaching to the HER2 protein and blocking it from receiving growth signals. Herceptin is approved by the U.S. Food and Drug Administration (FDA) to treat advanced-stage, HER2-positive breast cancers and to lower the risk of recurrence of early-stage, HER2-positive breast cancer with a high risk of recurrence.
Avastin, also given intravenously, works by blocking the growth of new blood vessels that cancer cells need to grow and function. A protein called vascular endothelial growth factor (VEGF) makes new blood vessels grow in cancer cells. Avastin blocks the VEGF protein. Avastin is approved by the FDA to be used in combination with Taxol (chemical name: paclitaxel) to treat metastatic, HER2-negative breast cancer that hasn't been treated with chemotherapy. Avastin also is used to treat advanced-stage lung, colon, and kidney cancer.
Taxotere also is given intravenously and is often used alone or in combination with other medicines to treat advanced-stage breast cancer.
Each of the 18 women in the study got six rounds of the Herceptin-Avastin-Taxotere combination. After those six rounds, some of the women continued to get all three medicines while other women got only Herceptin and Avastin. The women continued to be treated until the cancer progressed or unacceptable side effects developed.
Overall, 14 of the 18 women (78%) got some benefit from the Herceptin-Avastin-Taxotere combination. The cancers in half of the women didn't grow for more than a year.
- Eight women had a partial response, which means that there were signs of some improvement, but the cancer didn't go away completely.
- Six women had the cancer stay the same for some period of time; the cancer didn't grow, but it also didn't shrink.
- Two of these women had stable disease for more than 6 months; one other woman had stable disease for more than 2 years.
- Six of the 14 women that got some benefit later had the cancer grew or they died.
Heart damage (cardiotoxicity) is one possible side effect of Herceptin and Avastin. In this study, heart function was tested after every three rounds of treatment. Only one woman had some minor loss of heart function during treatment. Other side effects included low white blood cell counts, nausea and vomiting, and tearing of the eyes.
It's important to know that this study is very small and isn't completed. These results are very early results. Still, the results offer hope that the combination of Herceptin, Avastin, and Taxotere might be a good first treatment option for newly diagnosed metastatic breast cancer. More research is needed to better understand the benefits of the combination treatment, who might get the most benefits from it, and how it compares to current treatments.
If you've been diagnosed with HER2-positive, metastatic breast cancer you might want to talk to your doctor about these results and ask if they should affect your treatment plan.
Learn more about Herceptin and Avastin in the Breastcancer.org Targeted Therapies section. And stay tuned to Breastcancer.org to learn about other research results that may lead to better breast cancer treatments.