Doctors hoped Avastin (chemical name: bevacizumab) would be an effective breast cancer treatment when the U.S. Food and Drug Administration conditionally approved it for this use in 2008. The targeted therapy, which is also used to treat advanced-stage cancers of the lung, colon, and rectum, stops the growth of blood vessels that help tumors grow.
In late 2011, the FDA removed the breast cancer indication from Avastin, saying that follow-up studies hadn’t proven the drug was effective and safe for breast cancer.
Still, many doctors continue to use it off-label, prescribing it to women diagnosed with breast cancer if they think the medicine will offer benefits. Most commonly, Avastin is used in combination with chemotherapy to treat metastatic breast cancer. Metastatic breast cancer is cancer that has spread to parts of the body away from the breast, such as the bones or liver.
But new research has continued to be disappointing. The latest results found that adding Avastin to chemotherapy didn’t improve the outcomes of women diagnosed with early-stage, triple-negative breast cancer.
The study was published in the September 2013 issue of The Lancet Oncology.
The BEATRICE (Bevacizumab Adjuvant Therapy in Triple-Negative Breast Cancer) trial included nearly 2,600 women diagnosed with triple-negative (HER2-negative, estrogen-receptor-negative, and progesterone-receptor-negative), early-stage breast cancer. The researchers wanted to see if Avastin improved disease-free survival (the time the women lived without the cancer growing), as well as overall survival (the time the women lived, with or without the cancer growing).
After surgery, half the women were randomly picked to get either chemotherapy plus 1 year of Avastin. The other half got chemotherapy alone.
Most of the women got chemotherapy that contained an anthracycline.
After about 3 years of follow-up, the researchers saw no improvement in disease-free survival from adding Avastin to the women’s treatment plan:
- 82.7% of women who got chemotherapy alone were alive without the cancer growing
- 83.7% of women who got chemotherapy plus Avastin were alive without the cancer growing
There was no difference in overall survival between the two groups.
Avastin also increased the risk of severe side effects, including high blood pressure and heart problems.
The researchers also did some exploratory work to see if Avastin may benefit certain groups of women. Avastin works by blocking the growth of new blood vessels in cancer tumors, which starves the cancer of nutrients. The growth of new blood vessels in a tumor is called angiogenesis. Cancer cells make a protein, called vascular endothelial growth factor (VEGF), to stimulate angiogenesis. Avastin blocks VEGF. The exploratory work suggests that women with high levels of a receptor for VEGF (VEGFR-2) may benefit from adding Avastin to chemotherapy. Still, more work is needed before doctors know exactly how Avastin may benefit these women.
If you’ve been diagnosed with triple-negative breast cancer, you and your doctor will develop a treatment plan that will likely include chemotherapy and possibly targeted therapy medicines. No matter which treatments are recommended for you, you may want to talk to 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
If you're already getting Avastin and are responding to treatment, you may want to ask your doctor about this study. It's likely that your doctor will recommend that you stick with your treatment plan unless it stops being effective or unacceptable side effects develop. If your insurance company will not cover the cost of your Avastin treatment, talk to someone on your medical team about your options for getting help to afford continuing treatment.