Vaccine for ovarian, breast cancer shows promise

(CBS) A new vaccine that targets ovarian and breast cancer has shown promise in early studies, giving scientists hope they may be closer to stopping the deadly diseases.

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Known as PANVAC, the vaccine triggers the immune system to attack tumor cells.

"With this vaccine, we can clearly generate immune responses that lead to clinical responses in some patients," lead scientist Dr. James Gulley, director and deputy chief of the clinical trials group at the laboratory of tumor immunology and biology at the National Cancer Institute, said in a written statement.

For their research, published in the Nov. 8 issue of Clinical Cancer Research, scientists tested the vaccine on 26 patients, 12 of whom had breast cancer, 14 of whom ovarian. Most of the women had undergone prior chemotherapy treatment.

What did the scientists find? The vaccine caused women with breast cancer's disease progression to stall for 2.5 months, and their median survival was 14 months. Four had stable disease, meaning the cancer didn't grow nor shrink. Women with ovarian cancer reported a two month gap in disease progression, and survived for 15 months, and three had stable disease.

The cancer vaccine stalls cancer progression for only a couple of months? What's the big deal?

"That time frame is not anything to write home about," Gulley told WebMD. But he said that one of the women who had breast cancer currently shows no X-ray evidence of cancer after undergoing the experimental vaccine - four years later.

"It gives us encouragement that we may be on to something here," he said.

That 32-year-old woman was the youngest in the study, according to WebMD, but her cancer had spread to her liver and chest lymphnodes. At 18 months, there was no X-ray evidence of cancer. Gulley isn't sure why her treatment was so successful, but the woman had only undergone chemotherapy once. That suggests her immune system might have been stronger than the other women's.

But don't expect the vaccine on the market anytime soon. This was only a small study, so more needs to be done.

Gulley said interest in a cancer vaccine is increasing among scientists, but said in the statement that "more studies in the appropriate patient populations are required" to ensure safety, and which patients would benefit most.

The National Cancer Institute has more on cancer vaccines in development.