The immune system is our body's defense against infection and other foreign threats to health and well-being. Using a person's immune system to fight breast cancer is a very attractive idea.
Vaccines work by stimulating the immune system to mount a defense against a specific threat. The vaccines we know best are used to build defense against bacterial or viral infections. The idea of using a vaccine to try to prevent or treat breast cancer makes sense. However, research studies looking at the use of vaccines to prevent or treat breast cancer have, thus far, been disappointing.
A study suggests some early promise for one specific breast cancer vaccine, called Neuvenge. This vaccine was designed to stimulate the immune system to fight metastatic (advanced) breast cancers that are HER2-positive. About 1 out of every 4 breast cancers is HER2-positive. HER2-positive breast cancers tend to be more aggressive than HER2-negative breast cancers. A vaccine similar to Neuvenge, called Provenge, has shown promise in treating prostate cancer.
While this news is positive, there are several important things to know:
- These results about Neuvenge are from Phase I research. Phase I research primarily looks at whether or not a treatment is safe.
- This research suggested that Neuvenge is safe when given to women with breast cancer.
- This Phase I research did show some improvement in women with metastatic HER2-positive breast cancer. But we will need to have the results of Phase II research, which is now underway, before we can conclude that Neuvenge is a useful breast cancer treatment.
- Neither Neuvenge nor Provenge has been approved for use in treating cancer.
Targeted therapies, several of which are used today, are another way of using an immune system approach to fighting breast cancer. Targeted therapies use man-made immune system "warriors," called antibodies, which are identical or similar to those that might be produced naturally. For example, Herceptin (chemical name: trastuzumab) is a targeted therapy that consists of an immune system-like antibody that blocks the HER2 protein in breast cancer cells, which stops or slows the growth of the cancer.
If you are a woman who is at very high risk for breast cancer, or who is currently being treated for advanced breast cancer, you may want to talk to your doctor about participating in a breast cancer vaccine trial. There is excellent information on clinical trials at the National Cancer Institute and the National Comprehensive Cancer Network. Clinical trials looking at vaccines and breast cancer are our best hope for seeing that the promise of an effective breast cancer vaccine becomes a reality.