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.
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."
SOURCES: Odunsi, K. Proceedings of the National Academy of Sciences,
week of July 23-27, 2007; online early edition. Kunle Odunsi, MD, PhD, Roswell Park Cancer
Institute, Buffalo, N.Y. American Cancer Society: "How Many Women Get
Ovarian Cancer?" WebMD Medical News: "Ovarian Cancer: 4 Early Symptoms." FDA:
"Phase 1 Clinical Studies." News release, Proceedings of the National
Academy of Sciences.