Medical:Testing a breast cancer vaccine

Researchers are now testing two vaccines to see if they can reduce the risk or prevent breast cancer recurrence. The vaccines are made from peptides, or protein segments of the HER2/neu protein. One contains a peptide called, AE37, which stimulates an immune response against the HER2 protein and trains the CD4 helper cells to fight breast cancer. The second vaccine contains the peptide GP2, which stimulates the immune system’s CD8 killer cells. Both vaccines will contain GM-CSF (granulocyte monocyte colony stimulating factor), a substance made by the body to increase production of infection-fighting white blood cells.

Stewart says about half of women with breast cancer have a specific tissue type, called HLA-A2. These participants will be randomly divided into two groups. Half will receive the vaccine with the GP2 peptide plus GM-CSF. The other half will only get the GM-CSF. Women who are negative for HLA-A2 will also be randomized. Half of them will receive the AE37 vaccine and half will get just the GM-CSF.

The vaccine trial is a phase II study taking place at 9 sites across the U.S. A list of sites can be found at the end of this research summary. Participating women will receive an injection every three to four weeks, for a total of six shots. Earlier studies show the vaccines may reduce the risk of breast cancer recurrence by 17 to 18 percent. The most significant side effect of the vaccine is the development of skin irritation or welts at the injection site.