Ovarian Cancer Vaccine Shows Promise

July 23, 2007 -- Scientists today reported that an experimental ovarian cancer vaccine may help treat epithelial ovarian cancer, the most common type of ovarian cancer.

The experimental vaccine is still in the early stages of testing in ovarian cancer patients. It's designed to help prevent a relapse of ovarian cancer, researcher Kunle Odunsi, MD, PhD, tells WebMD via email. Odunsi works at the Roswell Park Cancer Institute in Buffalo, N.Y.

"The relapse rate in ovarian cancer is extremely high, up to 70%," Odunsi says.

Ovarian cancer has the highest death rate of cancers of the female reproductive system. The American Cancer Society estimates that this year, about 22,430 women will be diagnosed with ovarian cancer and about 15,280 women will die of ovarian cancer.

Ovarian cancer's high death rate is partly due to late detection. There aren't any routine screening tests to check for ovarian cancer. As a result, many women are diagnosed when ovarian cancer is already in its late stages.

Possible warning signs of ovarian cancer may include bloating, pelvic or abdominal pain, difficulty eating or feeling full quickly, and urinary symptoms (urge or frequency). But those symptoms don't always indicate ovarian cancer.

Ovarian Cancer Vaccine

The experimental ovarian cancer vaccine is designed to give the immune system a boost. Specifically, it raises blood levels of certain immune system cells called CD4 T-cells and CD8 T-cells.

The ovarian cancer vaccine is featured in this week's early online edition of Proceedings of the National Academy of Sciences.

Odunsi's team tested the vaccine in 18 women who had already had chemotherapy for new or recurrent epithelial ovarian cancer. The trial was a phase I clinical study, which is the first of three phases of human tests for new drugs.

The women got five injections of the ovarian cancer vaccine every three weeks. They received up to 15 injections.

The women's blood levels of CD4 T-cells and CD8 T-cells rose after getting the ovarian cancer vaccine and stayed above their prevaccination level for at least six months, and up to a year in some patients.

No major side effects were reported, though all of the patients briefly had pain at the injection site.

The study wasn't designed to test the vaccine's ability to thwart ovarian cancer or to increase ovarian cancer survival. But the results were "encouraging," note Odunsi and colleagues.

"Significant progress has been made," Odunsi tells WebMD. "However, we think the efficacy of the vaccine can be enhanced when combined with other strategies. ... We anticipated more definitive answers within the next five years."