A novel vaccine that stimulates the immune system to attack tumor cells is helping people with lung cancer (search) to live longer, researchers say.

Reporting here today at the European Society for Medical Oncology Congress, Charles Butts, MD, says that people treated with a lung cancer vaccine survived more than four months longer than those who received only standard cancer therapy.

While four months might not seem like a long time, these patients had an aggressive disease that would be expected to kill even more quickly, says Butts, a cancer specialist at the Cross Cancer Institute in Edmonton, Canada.

Even more exciting, he tells WebMD, is that among the subset of patients whose cancer was confined to the lung (early lung cancer), nearly twice as many given the vaccine survived for two years, compared with those given standard treatment.

"The results speak for themselves," Butts says. "There is a survival advantage that is difficult to ignore. This is huge."

Jose Baselga, MD, chairman of the scientific committee that chose which studies would be presented at the cancer meeting, agrees. "This is groundbreaking, the most important study of the meeting. There's a doubling in survival," he says.

Importantly, the same approach may be able to be applied to a wide variety of common cancers, including breast, colon, and prostate, notes Baselga, who was not involved with the trial.

How the Lung Cancer Vaccine Works

Unlike flu and other vaccines, most cancer vaccines under development are not intended to be given to healthy people to prevent disease. Rather, they are being developed to help patients with cancer bolster their immune system to better fight the disease.

In this case, the vaccine targets a specific protein that is altered in many lung cancer cells — encouraging the immune system to recognize the abnormal molecule and attack only those cells that carry it.

As an extra boost, patients are also given a drug that jump-starts the immune system, says Baselga, who is also chairman of oncology at the Vall D'Hebron University Hospital in Barcelona, Spain.

Because the vaccine targets only tumor cells, healthy cells are left unscathed. And that means the unpleasant side effects, such as hair loss and nausea, associated with traditional cancer medications are avoided, he says.

Lung Cancer Vaccine Nearly Doubles Survival

In the study, 170 people with lung cancer were randomly assigned to receive standard chemotherapy alone or chemotherapy plus the experimental vaccine. The vaccine is given as a shot every week for eight weeks, followed by boosters every six weeks for as long as it continues to work.

The people who received the vaccine lived an average of 17 months, compared with 13 months for those who were treated with chemotherapy alone, the study shows.

Among those people whose cancer was confined to the lung, the vaccine is working so well that 60 percent are still alive two years later — meaning that the researchers can't even yet calculate their average survival time. In contrast, patients in this subgroup who received chemotherapy alone survived an average of just 13 months, Butts says.

One patient is still alive and on the vaccine 3.5 years after beginning the trial, he adds.

Both Butts and Baselga stress that the vaccine is not yet ready for prime time. But the results of the trial, sponsored by the vaccine's manufacturers Biomira, Inc. of Edmonton, Canada, and Merck KGaA of Darmstadt, Germany, are favorable enough that a larger, longer study is expected to get underway next year.

"Should these findings be confirmed in the larger trial, this would be a true breakthrough," Baselga tells WebMD.

By  Charlene Laino, reviewed by  Charlotte E. Grayson, MD

SOURCES: 29th European Society for Medical Oncology Congress, Vienna, Austria, Oct. 29-Nov.2, 2004. Charles Butts, MD, senior medical oncologist, Cross Cancer Institute, Edmonton, Canada. Jose Baselga, MD, chairman, scientific committee, 29th European Society for Medical Oncology Congress; chairman, department of oncology, Vall D'Hebron University Hospital, Barcelona, Spain.