University of Virginia Health System

U.VA. RESEARCHER TO TEST OVARIAN CANCER VACCINE

A cancer researcher at the University of Virginia Health System is enrolling women to participate in a clinical research study to test a new vaccine for ovarian cancer, the most deadly of the gynecological cancers.

Developed by principal investigator Dr. William P. Irvin, associate professor of clinical obstetrics and gynecology, the vaccine is designed to prolong the remission of women newly diagnosed with ovarian cancer who have completed primary treatment, specifically surgery and chemotherapy.

The purpose of the vaccine is to prolong patients' remission, Irvin said. 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 of ovarian cancer.

Last year in the United States, approximately 26,000 women were diagnosed with ovarian cancer and an estimated 15,000 died from their disease, he said. 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, Irvin 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.

Unlike specific antigens that have been isolated and found to be unique for prostate cancer or melanoma, scientists do not yet know specific antigens for ovarian cancer, he said. As a result, Irvin's study relies upon the use of a vaccine constructed from the individual patients' cancer cells, radiated 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 will therefore 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; these cells are responsible for the ultimate recurrence of the cancer. It is hoped that the vaccine will alert the immune system to the foreign nature of the ovarian tumor cells that may persist following therapy and sustain a woman's remission from ovarian cancer longer, Irvin said.

Irvin has begun work on a second vaccine protocol that seeks to identify the specific antigens that may be unique to all ovarian cancer patients, in hopes that a generic vaccine could be developed -- 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 ovarian cancer 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 with relatively healthy immune systems will be enrolled in the study's first stage. If the preliminary study results are positive, more patients will subsequently be enrolled, Irvin said.

Women with ovarian cancer who are interested in participating in the trial may call the University of Virginia Cancer Center Clinical Trials office at (434) 243-6188.

June 12, 2001