Note to the News Media: This study was deemed scientifically newsworthy by organizers of the annual meeting of the American Society of Clinical Oncology. A press briefing is scheduled for 9 a.m. (EDT) Sunday, May 16, in Room 156 West (Level 1) of The Georgia World Congress Center in Atlanta.

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M. D. Anderson researchers report gene therapy success in preliminary study of localized advanced prostate cancer

ATLANTA--One of the country's leading research programs for prostate cancer has reported promising results of a preliminary study using gene therapy for combating prostate tumors.

Researchers at The University of Texas M. D. Anderson Cancer Center say the findings of the Phase I medical study may have a huge impact on future treatments for the disease, especially for men with localized advanced prostate cancer.

The research team, led by Dr. Christopher Logothetis, completed the Phase I study to assess the safety and efficiency of gene transfer to be achieved in patients with prostate cancer. The researchers hypothesized that effective transfer of the p53 gene would result in cancer cell death, resulting in reduction of tumor size. The research findings support the original hypothesis.

A total of 26 men with advanced localized prostate cancer who were candidates for a prostatectomy participated in the Houston study. Each man received an injection containing a synthetic form of the p53 gene, or an "adenoviral-p53 gene," produced by Introgen Therapeutics, Inc., of Austin, Texas. The injection went directly into the prostate tumor.

The size of the tumor was monitored with ultrasound over a six-week period. Subsequently, all of the men received a prostatectomy, after which the size of the prostate tumor was measured. Results of the study showed that seven of the men, or 27 percent of the study participants, experienced at least a 25-percent reduction in the size of the tumor. In addition to reduction in tumor size, the investigators saw increased cell death and intracellular transfer of the p53 protein, evidence of the potential efficacy of the gene therapy.

The primary purpose of the Phase I trial was to study the safety of increasing doses of the therapy in patients with locally advanced prostate cancer who were candidates for a prostatectomy, Dr. Logothetis noted.

"Our ultimate goal is to develop better alternatives for treatments with fewer complications," he said, adding that the findings with the p53 gene therapy may serve as the foundation for future treatment strategies.

Dr. Logothetis reported the findings on Sunday, May 16, during the American Society of Clinical Oncology's annual meeting in Atlanta.

He said future medical research in gene therapy might lead to improved treatments for men diagnosed with localized advanced prostate cancer. "Gene therapy, used in combination with other standard and new treatments for prostate cancer, may allow us to control the cancer without having to perform a prostatectomy," he said.

In the United States, prostate cancer is the most common malignancy in men and the second leading cause of cancer death in men. More than 179,000 men in the United States are expected to be diagnosed with the disease this year, with an estimated 37,000 related deaths.

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