"Even though our results are preliminary, the survival rates are an improvement over most published results of pancreatic cancer treatment studies," says Daniel Laheru, assistant professor at the Johns Hopkins Kimmel Cancer Center. Laheru is expected to present his findings in a press briefing at a joint meeting of the American Association for Cancer Research/National Cancer Institute/European Organization for Research and Treatment of Cancer in Philadelphia on November 15.
Until recently, most studies have shown pancreatic cancer survival rates at about 63 percent one year after diagnosis and 42 percent at two years. The long-term outlook is more grim - only 15 to 20 percent of patients with local disease are alive at five years. One 2003 study raised the survival bar higher, but with a chemotherapy and radiation regimen that Laheru describes as tough, with many side effects. "Since there is no universal standard for treating pancreatic cancer, it is difficult to make direct comparisons between all the studies," says Laheru.
In the current study, his team combined an immune-boosting vaccine with surgery and conventional postoperative chemotherapy and radiation. The vaccine, originally developed at Johns Hopkins, uses irradiated pancreatic cancer cells incapable of growing, but genetically altered to secrete a molecule called GM-CSF. The molecule acts as a lure to attract immune system cells to the site of the tumor vaccine where they encounter antigens on the surface of the irradiated cells. Then, these newly armed immune cells patrol the rest of the patient's body to destroy remaining circulating pancreatic cancer cells with the same antigen profile.
Patients get one vaccine injection eight to ten weeks after surgery, then four booster shots after chemotherapy and radiation. Laheru and his team completed enrolling patients in the study this past January. The average follow-up time is 32 months.
"It is important that we continue to follow these patients to know how the treatment will work in the long-term," says Elizabeth Jaffee, M.D., the Dana and Albert "Cubby" Broccoli Professor in Oncology and Pathology. "We're hopeful that these early results will hold true."
Jaffee and Laheru hope to begin multi-institutional studies in about a year. They are working with Hopkins pathologists from the Sol Goldman Pancreatic Cancer Research Center to analyze proteins from pancreatic cancer cells that may help them refine the vaccine's targets.
Pancreatic cancer strikes more than 30,000 Americans annually, and about the same number will die each year.
This research was funded by the National Cancer Institute and in part by Cell Genesys, Inc.
Under a licensing agreement between the Johns Hopkins University and Cell Genesys, Inc., the University is entitled to a share of royalty received by the University on sales of technology used in the study described in this news release. This arrangement is being managed by the University in accordance with its conflict of interest policies.
(Abstract #2229, A Safety and Efficacy Trial of Lethally Irradiated Allogeneic Pancreatic Tumor Cells Transfected with the GM-CSF Gene in Combination with Adjuvant Chemoradiotherapy for the Treatment of Adenocarcinoma of the Pancreas, Proceedings, AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics, November 2005.)
On the Web:
Johns Hopkins Kimmel Cancer Center: www.hopkinskimmelcancercenter.org
Johns Hopkins Sol Goldman Pancreatic Cancer Research Center: http://www.path.jhu.edu/pancreas/