Novel pancreatic cancer vaccine nudging survival rates higher

Main Category: Cancer / Oncology
Article Date: 19 Nov 2005 - 20:00 PDT

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A novel vaccine for pancreatic cancer appears to be nudging survival rates higher, say researchers at Johns Hopkins University School of Medicine. Their study, the first reported phase II study of a vaccine to treat this often lethal disease following surgery, has found in an early analysis that 88 percent of 56 patients tested are alive a year after treatment, and that two year survival is 76 percent. Researchers say that represents a significant bump over historical survival statistics, which are approximately 60 and 40 percent, respectively.

And if the Phase II trial mirrors results from its phase I predecessor, some patients may defy survival projections altogether, they say. In that study of 14 patients, three patients remain cancer free more than seven years after use of the experimental vaccine. Pancreatic cancer is the fourth leading cause of cancer death, and only about three percent of all pancreatic cancer patients are expected to survive beyond five years, according to Daniel Laheru, M.D., assistant professor of medical oncology at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins.

In this study, the vaccine was added to the standard treatment for patients whose cancer is confined to the pancreas. The first vaccine was delivered eight weeks after surgery, and that was followed a month later by a six-month course of chemotherapy and chemo-radiation. Three more vaccines were given every month thereafter, and the final dose was delivered after six months.

The vaccine is designed to boost a patient's immune response to pancreatic cancer cells that may still exist despite surgery and chemo-radiation treatment. It was derived from cancer cells extracted from two patients, which were genetically modified to secrete the immune stimulatory protein granulocyte-macrophage colony stimulating factor (GM-CSF). Because the vaccine is made up of cancer cells, it was irradiated to disarm any growth potential before being delivered to patients.

Researchers believe that once in the body, the vaccine cells produce GM-CSF for about five days, which is within the critical time period required to attract antigen presenting cells. This sets off an immune system response that may result in recognition of protein tags on the tumor cells, which are subsequently attacked, Laheru says. With an analysis of long-term responders in both of these clinical trials, the research team may be able to identify cancer-associated proteins that the immune system specifically reacts to, and modify the vaccine to display those antigens, he says. A phase III trial might also test use of the vaccine against traditional chemo-radiation treatment, he adds.

(Abstract 2229)

Founded in 1907, the American Association for Cancer Research is a professional society of more than 24,000 laboratory, translational, and clinical scientists engaged in cancer research in the United States and in more than 60 other countries. AACR's mission is to accelerate the prevention and cure of cancer through research, education, communication, and advocacy. This work is carried out through five major peer-reviewed scientific journals and high-quality scientific programs focusing on the latest developments in all areas of cancer research.

The National Cancer Institute, founded in 1971, is the principal United States government agency charged with coordinating the National Cancer Program. It facilitates international cooperation in clinical trials involving U.S. and foreign collaborating institutions.

The European Organisation for Research and Treatment of Cancer was organized in 1962 to conduct, develop, coordinate and stimulate laboratory and clinical research in Europe, and to improve the management of cancer and related problems by increasing the survival and quality of life for patients.

Warren R. Froelich
froelich@aacr.org
American Association for Cancer Research
aacr.org