A study found that women treated with Avastin (chemical name: bevacizumab) for advanced-stage breast cancer were 4 to 5 times more likely to develop congestive heart failure compared to women who didn't get Avastin. Still, the overall risk of heart failure was low -- fewer than 2% of the women who got Avastin developed heart failure.
Avastin is a targeted therapy medicine given intravenously. 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.
In early 2008, the U.S. Food and Drug Administration (FDA) approved the use of Avastin in combination with the chemotherapy medicine Taxol (chemical name: paclitaxel) to treat metastatic, HER2-negative breast cancer that hadn't been previously treated with chemotherapy. Avastin also is approved to treat advanced-stage cancers of the lung, colon, and rectum.
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 is associated with other serious side effects, including congestive heart failure, stroke, kidney malfunction, and reduced white blood cell count (neutropenia -- which can increase the risk of serious infection).
In this study, researchers analyzed the results of five other studies, all looking at using Avastin to treat advanced-stage breast cancer. All together, 3,784 women participated in the five studies and 2,366 of the women got Avastin. The other women either were treated with other cancer medicines or got no specific cancer treatment. None of the women had major heart disease before the studies started. The researchers reviewed all the women's records to see which women developed congestive heart failure.
- 36 of the 2,366 women (1.52%) who got Avastin developed congestive heart failure that affected their overall health (called clinically significant CHF)
- 4 of the 1,418 women (0.28%) who didn't get Avastin developed clinically significant CHF
Some of the women got a high dose of Avastin while others got a low dose. The risk of clinically significant CHF was the same with either dose.
On Dec. 16, 2010, the FDA announced that it is recommending removing the breast cancer indication from Avastin because it hasn't been shown to be safe and effective for that use.
The FDA had the following concerns about using Avastin to treat metastatic, HER2-negative breast cancer:
- Although research showed that combining Avastin with one of several chemotherapy medicines lengthened the time before the cancer grew or spread (progression-free survival), this benefit was small and overshadowed by the risk of serious side effects.
- Adding Avastin to chemotherapy didn't increase overall survival -- so women lived for about the same amount of time whether or not they got Avastin; the FDA feels that the small improvement in progression-free survival with no improved overall survival wasn't enough of a benefit, especially when the risk of serious side effects was considered.
- Adding Avastin to chemotherapy didn't ease metastatic breast cancer symptoms.
Removing the breast cancer indication from Avastin will be a process. This is the first step. The medicine itself is not being removed from the market and the recommendation will not have any immediate impact on its use in treating breast cancer. The FDA's recommendation to remove the breast cancer indication will not affect Avastin's approvals to treat advanced-stage lung, colon, and rectum cancers.
Many doctors believe the 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 that particular use is officially approved by the FDA. Still, loss of approval can make it less likely that insurers will pay for Avastin to treat breast cancer.
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
- 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 the FDA recommendation. 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.
Stay tuned to Breastcancer.org Research News for updates on the FDA recommendation regarding Avastin.