Activating body's immune system should fight tumors, researchers say
FRIDAY, Jan. 11 (HealthDay News) -- Therapeutic vaccines to fight ovarian and breast cancer are in the first stage of clinical trials to determine their safety and effectiveness, researchers report.
The vaccine for ovarian cancer, developed by Dr. George Coukos, an assistant professor at the University of Pennsylvania's division of gynecologic oncology, is designed to "re-educate" the patient's immune system cells to destroy cancer cells.
"This trial is a phase I/II trial that is just getting started," Coukos said during a presentation Thursday evening at a meeting of the Alliance for Cancer Gene Therapy, in Greenwich, Conn. The trial will include some 30 women with ovarian cancer.
The vaccine makes use of the patients' own tumor cells, which are then put into the patients' own dendritic cells. Dendritic cells are responsible for initiating the body's immune response, Coukos said.
In this trial, two new drugs -- called DCVax-L and DCVax-L primed -- are being used to aid in growing new immune cells. The trial is also testing which of the drugs is most effective.
The "re-educated" dendritic cells are then injected back into the patient at intervals spanning as long as three years, according to Coukos. Once in the body, these cell are designed to attack the cancer cells.
Using this therapy in mice produced dramatic results, Coukos said. "Typically, the translation from mouse to human is always disappointing," he said. "We are hoping, based on other clinical data, there will be a good response."
By creating individualized ovarian cancer vaccines composed of a patient's own cells, Coukos believes that his tailored approach will be effective. "We actually use the patient's own tumor and the patient's own blood. So it's not one-type-of-therapy-fits-all. Everybody gets their own individualized treatment," he said.
As with all early trials, the outcome isn't assured. "We need to keep trying," Coukos said. "One trial will not provide all the answers we need."
There were some 22,430 new cases of ovarian cancer diagnosed in the United States in 2007, and approximately 15,280 deaths from the disease, according to American Cancer Society estimates. In most cases of ovarian cancer, the disease has already reached late stage and spread beyond the ovaries before it is detected and diagnosed. Because the cancer has spread to other parts of the body -- metastasized -- the prognosis is typically not good, Coukos said.
After surgery and chemotherapy, late-stage ovarian cancer usually recurs in 18 months to 20 months. When it does reappear, it is considered incurable and usually results in death, even with aggressive chemotherapy, Coukos noted.
In another presentation at the meeting, Dr. Leisha A. Emens, an assistant professor of oncology at Johns Hopkins University, discussed her work on a new therapeutic vaccine to fight breast cancer.
Of the six types of breast cancer, the vaccine is designed to treat HER-2/neu disease, which is particularly aggressive. The vaccine is designed to marshal the body's immune response to fight the cancer, she said.
Emens has also found that combining the vaccine with currently used chemotherapy drugs such as cyclophosphamide and doxorubicin increased the vaccine's effectiveness. In the current trial, women with advanced breast cancer are receiving combinations of vaccine and chemotherapy.
Emens said she's also working on a vaccine that, along with chemotherapy, would prevent blood vessels from feeding the cancer, essentially starving and killing the cancer cells.
"We have enrolled eight folks and have seen evidence for immunity," Emens said. "It is important that now that we are on the verge of developing immune-based and gene-therapy-based approaches for treating cancer to integrate these novel approaches into the standards we already have, so we can maintain the progress and improve it." she said. "By doing that, we will be able to cure breast cancer in our lifetime."
Breast cancer is the most common cancer among American women, other than skin cancer, and is the second leading cause of cancer death in women, after lung cancer. About 178,480 U.S. women will be diagnosed with invasive breast cancer this year, and about 40,460 will die from the disease, according to the American Cancer Society.
The Alliance for Cancer Gene Therapy says it's the only public charity in the United States that is dedicated exclusively to cancer gene therapy research, with 100 percent of funds raised by the group going directly to research.
For more on ovarian cancer, visit the U.S. National Cancer Institute.
SOURCES: George Coukos, M.D., Ph.D., assistant professor of obstetrics and gynecology, University of Pennsylvania, Philadelphia; Leisha A. Emens, M.D., Ph.D., assistant professor of oncology, Johns Hopkins University, Baltimore; Jan. 10, 2008, presentation, Alliance for Cancer Gene Therapy, Greenwich, Conn.
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