Doctor tests vaccine for ovarian cancer

By Catherine Seigerman

U.Va. cancer researcher is working on a unique vaccine that may use the body’s cancer cells to trigger an immune reaction. Dr. William P. Irvin is enrolling women in a clinical study to test a new vaccine for ovarian cancer, the most deadly of the gynecological cancers.

“Seventy-five percent of women diagnosed with ovarian cancer will have advanced stage disease at the time of their initial diagnosis, because no effective screening program is currently available for early detection,” said Irvin, associate professor of clinical obstetrics and gynecology and principal investigator of the vaccine.

“The purpose of the vaccine is to prolong patients’ remission” after they have completed primary treatment for ovarian cancer, specifically surgery and chemotherapy, Irvin said.

Approximately 26,000 U.S. women were diagnosed with ovarian cancer last year, and an estimated 15,000 died from the disease. Lack of effective screening makes ovarian cancer the fourth most deadly cancer for women, after lung, breast and colon cancers, and causes more deaths than all other gynecological cancers combined, he said.

“With standard surgery and chemotherapy, approximately 50 percent of patients with advanced stage ovarian cancer will attain disease ‘remission,’” he said. “Unfortunately, 40 to 60 percent of these patients will subsequently develop recurrent cancer and will ultimately die from their disease. Anything we can do to prolong the remission, even make it permanent, is our goal.”

Scientists do not have specific antigens for ovarian cancer as they do for prostate cancer or melanoma. As a result, Irvin’s study relies upon the use of a vaccine made from the individual patients’ cancer cells, irrradiated so they cannot reproduce.

“The vaccine we make will be unique to each patient’s cancer, as opposed to a generic vaccine that would be designed to apply to all patients’ ovarian cancer,” he said.

“Our hope is that when the patient’s own reconstructed cancer cells are injected back into the body, the patient’s immune system will recognize the antigens unique to their ovarian malignancy and be stimulated to destroy any undetectable cancer cells remaining after treatment,” Irvin said.

Such cells always exist after ovarian cancer surgery but are generally undetectable and held responsible for the ultimate recurrence of the cancer. Irvin hopes that the vaccine will alert the immune system to the “foreign” ovarian tumor cells and sustain a woman’s remission longer.

Irvin has also begun work on a second vaccine protocol to identify the specific antigens that may be unique to all ovarian cancer patients. He hopes to develop a generic vaccine instead of having to develop one unique to each patient.

“We are moving into a new realm of cancer treatment, one that targets cancer cells at the very basic biologic mechanisms that enable them to grow and metastasize,” he said. “This therapy is being directed on the molecular level, through immunotherapy, gene therapy and inhibiting tumor growth. Confronting cancer on the biological level, rather than with new chemotherapies that inadvertently harm healthy cells as well as cancerous ones, will ultimately be less toxic for patients.”

The current vaccine study is funded by the Ovarian Cancer Research Fund and the U.Va. Cancer Center core grant from the National Cancer Institute of the National Institutes of Health. Twelve participants will be enrolled in the study’s first stage. If the preliminary results are positive, more patients will subsequently be enrolled, Irvin said.