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Pancreatic Cancer Vaccine Shows Promise: Presented at AACR-NCI-EORTC

By Maggie Schwarz

PHILADELPHIA, PA -- November 15, 2005 -- A phase 2 trial of a therapeutic pancreatic cancer vaccine shows improved 1- and 2-year survival compared with historical survival statistics.

These promising results "signal that the field of pancreatic cancer therapeutics is moving forward," said lead investigator Daniel Laheru, MD, Assistant Professor of Medical Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, United States.

Dr. Laheru presented the results here today at the International Conference of the American Association of Cancer Research, National Cancer Institute and European Organisation for Research and Treatment of Cancer (AACR-NCI-EORTC).

The evidence comes from the first reported phase 2 study of a vaccine to treat pancreatic cancer following surgery. In an early analysis, 88% of 56 patients tested are alive a year after treatment, and 2-year survival is 76%. Historical survival statistics are approximately 60% and 40%, respectively.

In a prior phase 2 trial of 14 patients given a lesser amount of vaccine, three patients (21.4%) remain cancer-free more than 7 years after taking the vaccine.

The vaccine was added to standard treatment for patients whose cancer is confined to the pancreas. The first vaccine was delivered 8 weeks after surgery, and followed 1 month later by a 6-month course of chemotherapy and chemo-radiation. Three more vaccines were given every month thereafter, and the final dose delivered after 6 months.

The vaccine boosts the immune response to pancreatic cancer cells persisting despite surgery and chemo-radiation. It is derived from cancer cells extracted from two patients, and genetically modified to secrete the immune-stimulatory protein granulocyte-macrophage colony stimulating factor (GM-CSF).

Once in the body, vaccine cells produce GM-CSF for about 5 days, the critical time period required to attract antigen presenting cells. This sets off an immune response that may results in recognition of proteins on the tumor cells, which are subsequently attacked.

With an analysis of long-term responders in both of these clinical trials, Dr. Laheru and colleagues may be able to identify cancer-associated proteins to which the immune system specifically reacts, and modify the vaccine to display those antigens. He added that a phase 3 trial might compare the vaccine with traditional chemo-radiation.

"Looking at the original 14 patients in the first trial, we see that they have demonstrated markers of immunity over 5 years," Dr. Laheru said. "Whether this immunity will protect them against a recurrence is still not clear."

"There's a lot of work going on [in the field of pancreatic cancer]," he said. "There's hope."

He projected that a follow-up, cooperative group study will start in 2007 and end in 2010.


[Presentation title: A Safety and Efficacy Trial of Lethally Irradiated Allogeneic Pancreatic Tumor Cells Transfected with the GM-CSF Gene in Combination with Adjuvant Chemotherapy for the Treatment of Adenocarcinoma of the Pancreas. C 28, Poster 204]

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