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Researchers are studying whether a vaccine similar to one being developed for prostate cancer would help treat breast cancer. The vaccine, called Neuvenge, is designed to target certain types of breast cancer cells in women whose cancers have spread to other organs despite treatment. The first phase of the study included a small number of women but showed that the vaccine appears safe enough to warrant further study. Neuvenge is a breast cancer vaccine under development by Dendreon Corporation, the maker of a prostate cancer vaccine called Provenge. In January 2007, Dendreon submitted a marketing application for Provenge, which the U.S. Food and Drug Administration accepted on a fast track basis, though the government requested that Dendreon show that Provenge can save lives. Dendreon is now also developing Neuvenge for breast cancer patients. In the first phase of their study, researchers tested the safety of Neuvenge in 18 women who had a certain type of advanced breast cancer that overexpresses the HER2 gene. HER2 (human epidermal growth factor receptor 2) is a gene found on the surface of cells that, when functioning normally, has been found to be a key component in regulating cell growth. However, when the HER2 gene is altered, extra HER2 receptors may be produced. This over-expression of HER2 causes increased cell growth and reproduction, often resulting in more aggressive breast cancer cells. HER2 gene is over-expressed in approximately 30% of breast cancer cases. In the study, the researchers made the vaccine using the women's own immune cells, so each vaccine was targeted to the patient. According to the researchers, the vaccine did not cause any serious side effects. It addition, it appeared to have a positive effect on the cancer of one patient and stabilize the cancers of three other patients for one year. "In addition to demonstrating that Neuvenge was safe and well tolerated, the T-cell responses seen in these patients and the prolonged disease stabilization in the absence of other anti-cancer therapies in many patients is promising," said John W. Park, M.D., associate clinical professor of medicine and neurosurgery at the University of California, San Francisco and lead author of the publication, in a Dendreon news release. "These observations are encouraging and are suggestive of the clinical benefit of Neuvenge, particularly in light of the aggressive cancer seen in these patients who had progressed while on standard therapy," said Park. "The findings warrant additional studies of Neuvenge for the many women with advanced breast cancer who have exhausted many of their treatment options." The researchers now plan to move to phase two of the study, during which they would attempt to show that the vaccine benefits patients. While the research is still very early, it provides more promise that "targeted" cancer treatment may be on the horizon. Currently, women whose cancers overexpress the HER2 gene are often treated with the drug Herceptin (generic name, trastuzumab). Herceptin works by attaching itself to the HER2 protein receptors on the surface of breast cancer cells. By binding to the cells, Herceptin can slow the growth and spread of tumors that have an overabundance of HER2. In addition, the FDA approved the drug Tykreb in 2007 to treat advanced breast cancer in combination with the chemotherapy drug, Xeloda (generic name, capectabine). Tykerb works in some HER2 positive breast cancers that have been treated with Herceptin and are no longer benefiting.
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