Source Newsroom: Society of Gynecologic Oncology
Embargoed until February 11, 1998
Contact: Johanna Spangenberg
Phone: (703) 527-7424
Contact: Barbara Halpern
Phone: (202) 332-7353
NEWS ROOM: February 6-11, 1998
Walt Disney World Dolphin
Orlando, Florida (407) 560-2675
VACCINE CREATED FROM GENE THERAPY FOUND TO BE EFFECTIVE IN TREATING OVARIAN CANCER
ORLANDO, FL -- A hope for a more effective weapon against ovarian cancer may soon become a reality. New medical research has found that genetically engineered chemotherapy-resistant tumor cells can express a "suicide gene" that renders sensitivity to a new drug, which results in the killing of tumor cells.
The study's authors found that genetically altered tumor cells expressing the HSV-TK gene, used previously as a vaccine therapy for multiple cancers, may be equally effective in treating women with ovarian tumors. Experiments with mice and a Phase I clinical trial involving 17 patients with recurrent chemotherapy-resistant ovarian cancer revealed that the vaccine therapy could be associated with tumor regression in the laboratory animals, and suggested future positive use in human patients.
This new medical research was conducted by William R. Robinson, MD, April O'Quinn, MD, and Jan Adams, RN, Department of Obstetrics and Gynecology, and Scott M. Freeman, MD, and Anupuma Munshi , both Department of Pathology staff, all from Tulane University School of Medicine, New Orleans, LA; and Depaak M. Saharsabudhe, MD, and Camille N. Abboud, MD, from the Section of Hematology, University of Rochester, Rochester, NY. Their efforts were supported in part by a the Brenman Oncology Fund and a grant from the National Institutes of Health.
Dr. Robinson will represent his colleagues as he presents the research results on February 11, 1998, before the 29th Annual Meeting of the Society of Gynecologic Oncologists (SGO) being held at the Walt Disney World Dolphin Resort, Orlando, FL, February 7-11, 1998.
Background: Ovarian cancer is this country's most lethal female malignancy. Last year, this disease occurred in approximately 26,000 women and was the cause of 14,000 reported deaths. In most cases, when ovarian cancer is first diagnosed, the disease has already spread, leading to a five year survival rate of just 30%. Treatment options for ovarian cancer are generally limited to surgery and chemotherapy, the latter providing an initial response generally followed by tumor recurrence within a few months. Immunotherapy, an attempt to boost the immune system's function, or a way to attack the cancerous cells directly, has been investigated as an alternative or adjuvant to traditional chemotherapy but preliminary trials have been disappointing.
To enhance chemotherapeutic treatments, the medical researchers proposed that transferring the Herpes Simplex Virus-Thymidine Kinase (HSV-TK) gene into the cancer cells would create a "suicide gene." Ovarian cancer tumor cells carrying this mutated gene would be susceptible to the antiviral drug, ganciclovir (GCV). In addition, after treatment, nearby tumor cells would be killed as a result of a "bystander effect" whereby unmodified tumor cells are also killed.
Methodology: To test their theory under ideal conditions, the researchers injected mice bearing intraperitonital tumors with gene modified cancer cells and GCV. The mice were evaluated for survival and immune response by analysis of tumor samples collected post-treatment. Following the animal studies, 18 female patients with recurrent, chemotherapy-resistant ovarian cancer were enrolled. All of the women completed the therapy; none were removed from the experimental treatment due to related toxicity.
Results: The first stage of the research using mice revealed that the transfer of the HSV-TK genetic material to the ovarian cancer cells caused the cancers to become susceptible to GCV-medicated cell kill. Tumor regression did occur in the mice, but was noticed more frequently in mice that were immune competent versus those that were immune deficient.
The Phase I trials with human patients, all with advanced ovarian cancer, found that this form of treatment is technically feasible. The survival rate of this group of women with advanced ovarian cancer was poor (averaging 11 months); however, the results found in four of the patients show promise. Accordingly, a new round of testing is now in the planning process.
The Society of Gynecologic Oncologists (SGO) is a professional society of physicians who specialize in gynecologic oncology. SGO is the only U.S. based medical organization dedicated to the prevention, detection and cure of female cancers. Gynecologic oncologists are cancer specialists trained in all the effective forms of treatment of gynecologic cancers (surgery, radiation therapy, chemotherapy and experimental treatments) as well as the biology and pathology of gynecologic cancers. The organization is comprised primarily of gynecologic oncologists as well as medical oncologists, radiation therapists and pathologists all of whom have a primary professional commitment to the treatment of women with gynecologic malignancies including those of the ovaries, endometrium, uterus, cervix vagina, vulva and trophoblastic disease.
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Editor's Note: For a complete copy of the complete manuscript or to schedule an interview with Dr. Robinson contact Johanna Spangenberg (703) 527-7424.
The Informatics Committee of the Society of Gynecologic Oncologists (SGO) has led the development of the Women's Cancer Network under the direction of Drs. Mitchell Morris and Ivor Benjamin. For more information vist the following web site http://www.wcn.org