Patients with advanced pancreatic cancer, one of the most deadly malignancies, may live a little longer when treated with two therapeutic vaccines, new research suggests, Newsmax Health reports.

In a study of 90 patients, this combination approach -- GVAX Pancreas vaccine followed by CRS-207 vaccine -- improved survival by several months compared with GVAX alone, researchers found. The greatest gain was seen in patients who had at least two doses of GVAX and at least one dose of CRS-207.

Stephen Isaacs, CEO of Aduro BioTech of Berkeley, Calif, believes the effect would be even more dramatic for patients given the vaccines in an early stage of the disease.

Dr. Vincent Vinciguerra, a professor of medicine at Hofstra North Shore-LIJ School of Medicine in New York, said this approach is more targeted than chemotherapy and much less toxic.

Isaacs said the treatment, if approved, will cost $50,000 or more.

After a year, almost one-quarter of those treated with the vaccine combination were still alive, compared with 12 percent of those treated with the single vaccine.

Moreover, patients who received at least three doses of both vaccines and those who received two doses of GVAX and at least one dose of CRS-207 survived an average of 9.7 months compared with 4.6 months for those who received GVAX alone, the findings showed.

Side effects of the combination vaccines were relatively mild and did not get worse with each dose, the investigators noted. The most common side effects were fever and chills.

The GVAX vaccine is made up of pancreatic cancer cells that have been genetically modified to emit a protein that stimulates the immune system. To boost its effectiveness, the vaccine is given with a low dose of a common cancer drug, cyclophosphamide.

The second vaccine, CRS-207, is a weakened form of the bacterium Listeria monocytogenes that is genetically modified so it's safe for humans but still able to stimulate the immune system.