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| |  Cancer Institute Seeks Patients With Recurring Brain Tumors For New Trial SANTA MONICA, Calif. -- April 24, 1997 -- The John Wayne Cancer Institute is seeking individuals with recurring malignant brain tumors that have failed to respond to standard therapy such as radiation, chemotherapy and surgery to participate in a clinical, experimental research study. Patients should be between the ages of 18 and 70 years of age and not neurologically disabled. Dr. Robert W. Rand of the John Wayne Cancer Institute, Dr. Raj Puri of the Food and Drug Administration (FDA), and Drs. Robert Kreitman and Ira Pastan of the National Cancer Institute (NCI) have developed an innovative new and experimental method of attacking deadly recurrent malignant brain tumors using Pseudomonas exotoxin, a natural poison from a common bacterium. They received U.S. Food and Drug Administration (FDA) approval to begin Phase I clinical trials of Pseudomonas exotoxin and its delivery system. Rand, director of Neuro-Oncology at the John Wayne Cancer Institute, will lead the clinical evaluations in brain tumor patients. The research treatment revolves around Interleukin 4, a hormone-like substance (produced by the body's white blood cells). Seven years ago, Puri, laboratory chief at the Center for Biologics Evaluation and Research, FDA, discovered that solid cancer cells have receptors for IL-4. The IL-4 toxin is internalized in the cancer cell after binding to its surface receptor. Puri, M.D., Ph.D., of the FDA, Kreitman, M.D. and Pastan, M.D. of the NCI, developed a truncated molecule of the Pseudomonas toxin that would attach to IL-4 receptors on the cancer cells. Then they studied its effect on brain tumors. They found that once at the cancer-cell site, the toxin molecule enters into the brain cancer cell because of the presence of the IL-4 receptor. According to Puri, in a matter of hours, the toxin destroys the cancer cell's ability to produce protein and stay alive in the laboratory and in animal models; in two to three weeks, most tumors will shrink. Most healthy brain cells do not have IL-4 receptors, and they are not exposed to the bacterium's toxin. The Pseudomonas exotoxin will be delivered directly into the recurrent malignant brain tumor by a tiny plastic tube inserted through a small opening in the skull. According to Rand, "Applying the drug directly to the tumor will maximize its cancer-killing capacity while minimizing potential side effects. Actually, we suspect there will be virtually no side effects from the drug." Recurrent glioblastomas and malignant astrocytomas are common tumors that originate in the brain and are universally fatal in a matter of months. If the tumor is 1 1/2 inch in diameter or larger, most patients will die within a year after the diagnosis of recurrence. It could even be more fatal depending on the location within the brain. "In general, radiation, surgery, and chemotherapy may give the patient a few extra months, but they can't cure the cancer. That's what makes this IL-4 toxin approach so exciting. If it works as we believe it will, we could extend a patient's life span without affecting their quality of life. It's far too early to call this a cure, but we suspect this could be an effective treatment. However, only time will tell if the drug can actually shrink the patients' brain tumor and permanently prevent it from coming back," Rand said. This stage of the FDA testing evaluates potential side effects of experimental treatments.
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