Jan. 5, 2001 -- Early results with a new vaccine for the treatment of pancreatic cancer are showing promise. During its first testing in humans, the vaccine has proven to safely and effectively stimulate the immune system in a desirable way. In a few individuals with this deadly disease, the vaccine appears to have markedly extended their life expectancy.
Cancer of the pancreas is relatively rare, but it is quite deadly. It strikes more than 27,000 people each year. Fewer than 5% of people diagnosed with pancreatic cancer survive five years; 28,000 people die from pancreatic cancer annually.
Vaccines are typically thought of as a way of preventing disease. In cancer, however, they are used along with other therapies to fight the disease, says expert Tony Hollingsworth, PhD. All vaccines are designed to encourage the immune system to fight disease, but in the case of cancer, patients are first treated with other therapy, such as surgery, radiation, and chemotherapy, to get rid of the bulk of the disease. Vaccines are then used to stimulate the immune system to find and destroy any cancer cells that may be remaining, with the ultimate goal of extending life. Hollingsworth is a professor and head of the Specialized Program of Research Excellence (SPORE) on Pancreatic Cancer at the University of Nebraska in Omaha. His research team is working on developing other types of pancreatic cancer vaccines.
"The diagnosis of pancreatic cancer is, for most patients, a death sentence," study co-author Elizabeth M. Jaffee, MD, tells WebMD. "Even patients who undergo surgical [removal of the cancer] usually [have a] recur[rence] in 6-12 months and die within 1-2 years of diagnosis. This is one of a few studies looking at activating the immune system in patients with a disease that has only one approved therapy, Gemzar, [which] is approved for enhanced quality of life [and] does not significantly extend life." Jaffee is an associate professor of oncology, pathology, immunology, and cell and molecular medicine at Johns Hopkins University School of Medicine in Baltimore, Md.
Jaffee and her colleagues studied 14 people with pancreatic cancer who had had the cancerous portion of their pancreas removed surgically eight weeks previously. These individuals were treated with various doses of a cancer vaccine made with lab-grown cancer cells that had been genetically modified to contain an immune-boosting gene called GM-CSF. In previous studies, this vaccine had been shown to cure tumors in mice. Twelve of the participants in the study then went on to additional treatment with radiation and chemotherapy, and six received up to three additional monthly doses of the vaccine. The study is published in the Jan. 1 issue of the Journal of Clinical Oncology.
The vaccine proved safe, with redness and itchiness of the skin at the site of the vaccine injection being the only significant side effects. Individuals who received the highest doses of the vaccine responded with activation of several parts of their immune systems. "Three [of these] patients [who] ... were expected to [have their cancer] recur within 6-12 months from diagnosis are between 3 and 3.5 years from diagnosis" and still disease free, says Jaffee.
"New drugs are being developed for this deadly disease," says Jaffee. "The only way to truly know whether these new drugs including this vaccine will help patients in the future is to refer patients for ongoing studies. ... I would like to encourage my colleagues and [individuals with pancreatic cancer] to enroll ... in our future studies so that we can adequately assess the efficacy of this therapy. ... This was an early study. We need to continue testing the drug for safety and efficacy. The only way to do this is to enroll patients in studies."
"Not everyone would be a candidate for this, but it's important for people with pancreatic cancer to know that there are groups that are trying novel things," says Hollingsworth. "If they are interested in tumor vaccines, ... this would be a reasonable state-of-the-art procedure that would be available [within the context of a clinical trial] if they are eligible for it."
This research received funding from the National Cancer Institute.