A study suggests that adding Avastin (chemical name: bevacizumab) to any of several common chemotherapy regimens for metastatic, HER2-negative breast cancer can lengthen the time before the cancer grows (called progression-free survival) compared to the same regimen without Avastin.
These results were presented at the 2010 American Society of Clinical Oncology (ASCO) annual meeting.
Metastatic breast cancer is cancer that has spread outside the breast to another part of the body.
Avastin is a targeted therapy and 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 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. Avastin is given intravenously.
In the RIBBON-2 trial, 684 women diagnosed with metastatic, HER2-negative breast cancer were being treated with a common chemotherapy regimen. Half of the women had Avastin added to that chemotherapy regimen. The researchers compared the results of treatment with the chemotherapy regimens plus Avastin to the chemotherapy regimens alone. In all but one regimen, adding Avastin lengthened progression-free survival time somewhat.
When Avastin was combined with a taxane regimen such as Taxol (chemical name: paclitaxel) Taxotere (chemical name: docetaxel), or Abraxane (chemical name: albumin-bound or nab-paclitaxel), progression-free survival was 8 months compared to 5.8 months without Avastin.
When Avastin was combined with a Gemzar (chemical name: gemcitabine) regimen, progression-free survival was 6 months compared to 5.5 months without Avastin.
When Avastin was combined with a Xeloda (chemical name: capecitabine) regimen, progression-free survival was 8 months compared to 5.8 months without Avastin.
The only chemotherapy regimen that didn't have longer progression-free survival when Avastin was added was the Navelbine (chemical name: vinorelbine) regimen. Progression-free survival was 5.7 months with Avastin compared to 7 months without Avastin. But only a small number of women got Navelbine with or without Avastin, so these results aren't as reliable as the results for the other chemotherapy regimens.
Even though progression-free survival was longer, adding Avastin to the chemotherapy regimens didn't improve overall survival. This means the women lived for about the same amount of time whether or not they got Avastin.
Some doctors are concerned that the benefits of Avastin don't outweigh the risk of side effects and the potentially high cost of treatment. Common side effects of Avastin include high blood pressure, nosebleeds, 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. Still, many doctors believe that the potential benefits of Avastin for certain women diagnosed with metastatic breast cancer are worth the risks and costs of treatment.
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, consider asking your doctor about:
- 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.