Avastin (chemical name: bevacizumab) is approved by the U.S. Food and Drug Administration (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. Metastatic breast cancer is cancer that has spread outside the breast to another part of the body. Avastin also is used to treat advanced-stage lung, colon, and kidney cancer. Avastin is given intravenously.
Avastin is a targeted therapy medicine. Avastin 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.
The FDA is considering whether to continue the approval for using Avastin with Taxol to treat metastatic breast cancer, as well as whether to approve using Avastin in combination with several other chemotherapy medicines to treat metastatic breast cancer.
When making decisions about medicine approval, the FDA asks expert panels for their opinions. For cancer medicines, the FDA consults with the Oncology Drug Advisory Committee (ODAC). The ODAC reviews FDA analysis of research results and then votes on the approval. The FDA considers the ODAC vote as well as the research results when making an approval decision.
The FDA analysis of research on Avastin shows:
- adding Avastin to one of several common chemotherapy regimens for metastatic, HER2-negative breast cancer lengthened the time before the cancer grew (progression-free survival)
- adding Avastin to chemotherapy didn't increase overall survival; this means that women lived for about the same amount of time whether or not they got Avastin with chemotherapy
- adding Avastin to chemotherapy didn't ease metastatic breast cancer symptoms
In the AVADO study, 736 women diagnosed with HER2-negative, metastatic breast cancer got one of three treatments:
- Taxotere (chemical name: docetaxel) plus a low dose of Avastin
- Taxotere plus a high dose of Avastin
- Taxotere alone
This was the first treatment for metastatic breast cancer the women received (called first-line treatment). Taxotere, like Taxol, is a taxane chemotherapy.
The AVADO study found that women who got both Avastin and Taxotere went a month longer before the cancer started growing again compared to women who got only Taxotere. Still, overall survival was the same for all three groups.
In the RIBBON-1 study, 1,237 women diagnosed with HER2-negative, metastatic breast cancer got one of three types of chemotherapy medicine, either in combination with Avastin or alone:
- an anthracycline
- a taxane
- Xeloda (chemical name: capecitabine)
This was the first treatment for metastatic breast cancer the women received.
The RIBBON-1 study found that women who got both chemotherapy and Avastin had a longer time before the cancer grew compared to women who got only chemotherapy:
- progression-free survival was 1.2 months longer for women who got Avastin and either an anthracycline or taxane chemotherapy compared to women who got either type of chemotherapy alone
- progression-free survival was 2.9 months longer for women who got Avastin and Xeloda compared to women who got Xeloda alone
Still, overall survival was the same for all the women in RIBBON-1.
Some doctors are concerned that without better overall survival, the benefits of Avastin don't outweigh the risk of side effects and the potentially high cost of treatment. Side effects of Avastin include high blood pressure, bleeding (nosebleeds, for example), and extra protein in the urine. People treated with Avastin also may have weakness, pain, and diarrhea. Avastin also may cause other serious side effects, including a higher risk of stroke or heart problems, kidney malfunction, and reduced white blood cell count (neutropenia).
In the AVADO and RIBBON-1 studies, the women who got Avastin combined with chemotherapy were more likely to experience high blood pressure, bleeding, and low white blood cell counts with fever (suggesting possible infection) compared to women who got only chemotherapy.
Still, many doctors believe that the potential benefits of Avastin for certain women diagnosed with metastatic breast cancer are worth the risks and cost of treatment. Doctors can choose to use Avastin to treat metastatic breast cancer whether or not the particular use is officially approved by the FDA.
If you've been diagnosed with metastatic breast cancer, you and your doctor will develop a treatment plan that will likely include chemotherapy and possibly hormonal therapy and/or targeted therapy medicines such as Avastin. No matter which treatments are recommended for you, you may want to ask your doctor:
- why each treatment is recommended (including any combinations)
- treatment timing and sequence
- the expected benefits, risks, and side effects of each treatment
You can learn more about Avastin in the Breastcancer.org Targeted Therapies section.
Stay tuned to Breastcancer.org Research News for updates on Avastin approvals.
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