Breast cancer vaccine looks safe, study shows
WASHINGTON (Reuters Life!) - A therapeutic vaccine designed for breast cancer appears to be safe in women with advanced disease and shows signs of actually slowing down tumor growth, U.S. researchers reported on Friday.
Dendreon Corporation, maker of the Provenge prostate cancer vaccine, calls the new vaccine Neuvenge. It targets a type of breast cancer called her2/neu-positive breast cancer, which affects between 20 percent and 30 percent of breast cancer patients.
Like Provenge, Neuvenge is made using immune cells from the cancer patient, so it is a tailor-made vaccine.
Dr. John Park of the University of California, San Francisco and colleagues tested it in a phase I trial with 18 women with advanced her2/neu-positive breast cancer, whose cancer had spread despite treatment.
In the Journal of Clinical Oncology, the researchers report that the vaccine did not cause any serious side effects and appeared to help at least one patient.
"We saw a partial response, meaning a reduction in the size of tumor area in one patient that was certainly attributable to the treatment," Park said in a telephone interview.
In three other women, their cancer appeared to stabilize for as long as a year, something that could have been due to treatment, Park said.
Park said the effects justify moving from the phase I safety trial to a phase II trial, which would be designed to show the treatment actually helps patients. But that may not happen for a while, he said.
"The sponsor of this vaccine technology, Dendreon, is also associated with Provenge," Park said. "We on the breast cancer side are trying to encourage them to develop Neuvenge with the same vigor that they have tried to apply to Provenge, but it is not a company that has unlimited resources."
In January, the U.S. Food and Drug Administration accepted Dendreon's marketing application for Provenge on a "fast-track" basis, and in March an advisory panel said Provenge appeared reasonably safe. But the FDA has asked Dendreon to show the vaccine helps prostate cancer patients actually live longer.
Dr. Dave Urdal, chief scientific officer at Seattle-based Dendreon, said that data would not be available any sooner than next year, and perhaps not until 2010.
"The company currently is focused on its lead product, Provenge, so moving forward with the Neuvenge product is something that we haven't given guidance on," Urdal said in a telephone interview.
The delay in approval of Provenge has angered some patient advocacy groups.
Urdal said both Provenge and Neuvenge make use of immune system cells called CD4 helper T-cells. "This validates the approach. So there is more than one target and more than one cancer that potentially will benefit from this form of therapy," he said. Other companies are also working on cancer vaccines.
The her2/neu protein is over-expressed, meaning it is over-active, in several tumors including breast, colorectal and ovarian cancer.
What breastcancer.org says about this article…
Breast cancer vaccine looks safe, study shows
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.
The research reported here 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.
