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. Two studies found that adding Avastin to chemotherapy or hormonal therapy didn’t improve the outcomes of women diagnosed with either early-stage or metastatic breast cancer.
The studies were presented at the 2012 San Antonio Breast Cancer Symposium.
The BEATRICE (Bevacizumab Adjuvant Therapy in Triple-Negative Breast Cancer) trial included almost 2,600 women with triple-negative (HER2-negative, estrogen-receptor-negative, and progesterone-receptor-negative), early-stage breast cancer. After surgery, the women got either chemotherapy plus 1 year of Avastin or chemotherapy only.
After about 3 years of follow-up, the researchers saw no benefits to adding Avastin. There was only a slight improvement in disease-free survival (living without the cancer growing or coming back in parts of the body away from the breast).
Avastin also increased the risk of severe side effects, including high blood pressure and heart problems.
The LEA (Letrozole/Fulvestrant and Avastin) trial included 380 postmenopausal women diagnosed with HER2-negative, hormone-receptor-positive, advanced-stage breast cancer. After surgery, the women were assigned to get one of two treatment regimens:
- hormonal therapy medicine only -- either Femara (chemical name: letrozole) or Faslodex (chemical name: fulvestrant)
- hormonal therapy medicine plus Avastin
After about 4 years of follow-up, the researchers found that Avastin only slightly improved disease-free survival (living without the cancer growing) and didn’t improve overall survival (living whether or not the cancer grew).
As in the BEATRICE study, women who got Avastin had more side effects, including low white blood cell count and low platelet count.
Still, doctors aren’t ready to give up on using Avastin to treat breast cancer. More research is needed to figure out for exactly which types of breast cancer Avastin is a good 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. 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 these studies. 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.