4-2-2001

Contact: Vanessa Wasta
wastava@jhmi.edu
410-955-1287
Johns Hopkins Medical Institutions

Pancreatic cancer vaccine found safe in early study

Hopkins researchers say early tests of a pancreatic cancer vaccine show it is safe and successful in reaching immune system cells. A report on the findings is published in the Journal of Clinical Oncology, Vol. 19, No. 1, (January) 2001.

The vaccine, tested on 14 patients, uses lab-grown pancreatic cancer cells genetically-modified with the immune-boosting gene GM-CSF.

After surgery to remove the pancreatic cancers, patients received varying doses of the vaccine. Twelve of the 14 then underwent radiation and chemotherapy following the initial vaccination. Six patients received up to three additional monthly vaccinations.

Researchers found that several parts of the immune system were activated in three patients who got the highest doses. These patients remain disease-free more than 30 months after diagnosis. The other 11 patients showed no significant immune response. Side effects included only local skin reactions and redness and itchiness at the vaccine site for several days.

"This study was just a first step, but we are encouraged to find that it is safe and initiates an immune response in certain doses," says Elizabeth Jaffee, M.D., associate professor of oncology and lead author of the study.

To create the vaccine, researchers inserted the GM-CSF gene into pancreatic cancer cell lines. GM-CSF, the most potent gene known to activate the immune system, attracts immune cells to the site of the tumor vaccine where they recognize antigens found on the cancer cell surface. These antigens then serve as red flags, causing the immune system to seek out and destroy cancer cells elsewhere in the patient.

"Genetically-engineered vaccines like this could be used to ‘mop up' microscopic cancer cells left behind following surgery, chemotherapy, and radiation," says Jaffee. "We need to find the best combination of these treatments that will afford patients the best chance for survival."

Researchers caution that further studies are necessary to evaluate the vaccine's effectiveness. The second phase of trials at Hopkins could begin in early summer 2001.

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