Preliminary breast cancer vaccine study shows promise.

A vaccine designed to treat breast cancer has performed surprisingly well in an initial clinical study. In a phase II trial of 186 patients, the vaccine targeting the HER2/neu E75 peptide reduced the risk of recurrence by 50% in 101 breast cancer patients who were clinically disease free after treatment compared with those who were not treated with the vaccine. Immunized patients also had about a 20% improvement in diseasefree survival, according to a presentation at the San Antonio Breast Cancer Symposium in December, though this preliminary fi nding still needs to be tested in a randomized controlled trial. “Never did I think that a vaccine that was made up of a single peptide from a single antigen would be suffi cient to give us a clinical response or an alteration in clinical recurrence,” said Col. George E. Peoples, M.D., an oncologist at Brooke Army Medical Center in San Antonio. Because the research is in its early stages, the scientists don’t yet know how long the protective effect of the vaccine might last, he said. Immunized patients appear to need a booster after about 6 months, a hypothesis that an ongoing investigation is evaluating. The E75 vaccine is just one of several breast cancer vaccines in development, according to Philip Arlen, M.D., from the laboratory of tumor immunology and biology at the National Cancer Institute’s center for clinical research in Bethesda, Md. The research is focused on two different areas. One produces preventive vaccines against viruses that are known to cause certain types of cancer. Probably the best-known example is the human papilloma virus vaccine, which was recently approved for cervical cancer prevention. The other category centers on preventing cancer recurrence after initial treatment, the strategy refl ected in the studies of the E75 vaccine, Arlen said. Those treatment vaccines target a variety of different molecules, proteins, and protein fragments associated with tumor development and growth. The E75 vaccine, for example, targets a spe cifi c tissue type through a fraction of the HER2/neu protein. Other vaccines target tumor-associated proteins, like the MUC1 and CEA proteins in a vaccine Arlen has worked on.