Avastin (chemical name: bevacizumab) is a blood vessel growth inhibitor used off-label to treat certain advanced-stage or metastatic breast cancers. Avastin works by blocking the growth of new blood vessels that cancer cells depend on to grow and function. 

Avastin (chemical name: bevacizumab) is a targeted therapy that was approved by the U.S. Food and Drug Administration (FDA) in combination with Taxol (chemical name: paclitaxel) in February 2008 to treat people with metastatic HER2-negative breast cancer who haven't yet received chemotherapy for metastatic breast cancer.

On Nov. 18, 2011, the FDA announced that it had removed the breast cancer indication from Avastin because the drug has not been shown to be safe and effective for that use. The medicine itself is not being removed from the market and doctors can choose to use Avastin to treat metastatic breast cancer whether or not that particular use is officially approved by the FDA.

Avastin is also approved by the FDA to treat advanced cancers of the lung, colon, and rectum.

The FDA's removal of the breast cancer indication will not affect those approvals.


How Avastin works

Breast and other cancers need a good supply of blood to deliver the oxygen and nutrients that cancer cells need to grow, function, and multiply. To get that blood, cancer cells have ways of stimulating the growth of new blood vessels into the tumor. Avastin works by blocking this growth of new blood vessels, which starves the cancer of nutrients.

The growth of new blood vessels into a tumor is called angiogenesis (“angio” means blood vessel and “genesis” means beginning). Cancer cells can make a protein, called vascular endothelial growth factor (VEGF), to stimulate angiogenesis. Avastin blocks VEGF. By blocking VEGF, Avastin can interfere with the growth of new blood vessels into breast cancer tissue and starve the cancer. Doctors use the term anti-angiogenic to describe Avastin, because it works against the formation of blood vessels. Avastin can also change blood vessels already feeding the cancer in ways that make it harder for the cancer to survive and more vulnerable to chemotherapy. Avastin is an immune targeted therapy.


What to expect when taking Avastin

Avastin is given intravenously, which means the medicine is delivered directly into your bloodstream through an IV or a port. The first dose of Avastin takes about 90 minutes, and your treatment team will monitor you to make sure you don’t have a bad reaction. After that, it only takes about 30 minutes to an hour to get the other doses of Avastin. Avastin is usually given every 2 weeks.


Avastin side effects

Common side effects of Avastin can include:

These side effects can be managed, and in the case of high blood pressure, treated with standard medication. Other possible common side effects include:

  • weakness

  • pain in the bones, joints, and muscles

More serious side effects have been experienced in a small percentage of people taking Avastin, including blood clots in a vein, slow wound healing, perforation of the intestines, higher risk of stroke or heart problemskidney malfunction, and reduced white blood cell count. If you experience any of these serious side effects, your doctor will stop treatment with Avastin.

Since Avastin is given with chemotherapy, you may also experience chemotherapy side effects.


Avastin (bevacizumab) prescribing information. Genentech. San Francisco, CA. 2018. Available at

— Last updated on March 31, 2022, 7:11 PM