A new breast cancer vaccine is leaving researchers feeling encouraged. In a recent study that included 14 patients with metastatic breast cancer, half experienced no progression of their cancer one year following vaccination.
“The vaccine was safe,” says senior author and breast cancer surgeon Dr. William E. Gillanders. “There was an immune response to the vaccine in the majority of patients, and there was preliminary evidence to suggest that it would have a clinical impact as well.”
When compared to a control group of 12 patients who did not receive the vaccine, those who did showed prolonged progression-free survival. Translation: It took longer for the disease to progress among vaccinated patients.
This isn’t the first breast cancer vaccine, but it is different in that it targets a protein called mammaglobin-A. According to Gillanders, mammaglobin-A is dramatically over expressed in most breast cancers. This new vaccine, which was developed at Washington University School of Medicine in St. Louis, triggers the immune system to zero in on the protein. More specifically, it causes the body to find and eliminate cells that contain mammaglobin-A.
“This trial kind of confirmed that mammaglobin-A is a very attractive candidate for a breast cancer vaccine,” says Gillanders.
Among those who were vaccinated, few mild to moderate side effects were reported.
According to Gillanders, these types of trials can make it difficult to understand exactly how robust a vaccine is because the immune response is only being measured in the peripheral blood. This, he says, has raised some concerns about the ability to predict whether or not a vaccine will actually be effective.
“We’re planning to test our vaccine in patients with early-stage breast cancer before they have surgery, and then when we do the surgery we’ll be able to measure the immune response at the tumor site to see whether or not the vaccine can induce an immune response that is capable of killing the tumor,” says Gillanders.