Study: Vaccine for Breast, Ovarian Cancer Has Potential
Researchers Say a Breast Cancer Patient Who Got the Vaccine Is Now Cancer-Free
Interpreting the Findings
"The question is, why did we see this result in one patient?" he says. "All we can get from this trial are hints."
The woman, who remains disease-free, had a previous treatment with a different treatment vaccine. "That might have primed her immune system," Gulley speculates. She also had only one regimen of chemotherapy, perhaps keeping her immune system stronger.
Ideally, the vaccine may need to be given earlier in the course of the disease, he says. Further research should focus on predicting which patients would benefit most.
The PANVAC vaccine is one of several cancer vaccines being studied. It is a therapeutic or treatment vaccine, given after the disease occurs.
Other cancer vaccines being studied are preventive or prophylactic. They are meant to prevent cancer in those who are cancer-free.
Much more research is needed on the PANVAC vaccine for breast and ovarian cancer, Gulley says. It's difficult at this point to predict costs. However, he expects costs will not approach those for Provenge, the pricey treatment vaccine for prostate cancer approved by the FDA in 2010.
Provenge costs $93,000 for the one-month, three-dose treatment. Medicare covers it.
PANVAC ''is an off-the-shelf vaccine," Gulley says. "It's been developed at the National Cancer Institute. It's easier to make and logistically much simpler than the prostate cancer vaccine, which requires manipulation of the blood with each patient."
The study results show ''the promise and the frustration'' of developing therapeutic vaccines, says Vincent K. Tuohy, PhD, professor at the Lerner College of Medicine and an immunologist at the Cleveland Clinic Lerner Research Institute. He is developing a preventive vaccine for breast cancer.
He reviewed the study findings for WebMD.
The encouraging observation from Gulley's study, he says, is the ''durable resolution" of breast cancer in one patient. On the other hand, he says, the study shows the difficulty in prompting immune responses from patients whose cancer has spread and who have already had chemotherapy.
"There are many ways that mature tumors can turn off the immune response directed against them," Tuohy tells WebMD.
He agrees that the vaccine may work better in certain patients, including those who have had fewer chemotherapy regimens, and that giving the vaccine earlier is better.