New lung cancer vaccine may double survival rates.

New lung cancer vaccine may double survival rates

Just-completed clinical trials of an experimental anticancer vaccine suggest that it can double survival rates in early-stage lung cancer and provide a way to predict within months which patients will do well on this regimen, scientists reported this week. Other cancer researchers are praising the work for its potential significance but caution that more evidence is needed.

Although referred to as a vaccine, the antigen product used in this study is not a vaccine in the classic sense, since it does not prevent disease but instead fights existing disease by boosting the patient's immune response. Among 34 patients with early-stage squamous-cell and adenocarcinoma lung cancers, the immunotherapy increased five-year survival rates to between 53 and 75 percent, depending on how the vaccine was given after surgery, compared with 33 percent in those treated with surgery alone. Ariel C. Hollinshead and her co-workers at George Washington University in Washington, D.C., developed the vaccine by isolating and purifying an antigen found on the surface of lung cancer cells, which they believe is a specific marker for lung tumor cells. They then injected these tumor-associated antigens into patients once a month for three months.

They noted that within five to six months after treatment, the patients who did not respond to the vaccine had very low or no serum-antibody responses to the antigen, as well as poorer cell-mediated immunity responses. By assaying these responses, clinicians can predict the vaccine's effect, says Hollinshead.

She reported the latest clinical trials this week at the American Cancer Society's 30th annual science writer's seminar in Daytona Beach, Fla. The studies, done in collaboration with Roswell Park Memorial Institute in Buffalo, N.Y., appear promising. However, the results -- to appear in the JOURNAL OF CANCER -- apply only to people diagnosed during the early stages of disease, a group that includes only 20 to 25 percent of squamous-cell lung cancers. Squamous-cell cancers account for 80 percent of all lung cancers seen in the United States and are associated with tobacco smoking.

Until more data are collected, the results should be viewed with "suppressed enthusiasm," says John P. Minton of the Ohio State University College of Medicine in Columbus. Commenting on Hollinshead's work during the seminar, Minton pointed out that effective treatments for lung cancer have been elusive, despite the importance of the disease -- 152,000 new cases are expected this year, with a five-year survival rate of only 13 percent for all types combined. But Minton calls the vaccine results a "new bright light of hope."

Hollinshead's study should be regarded as a "state-of-the-art" effort that can point the way to related efforts against cancer, agrees Frank J. Rauscher, the American Cancer Society's senior vice-president for research. He does, however, say that he will have reservations about the findings until the work is duplicated by other researchers. "I'm not so sure the data are good enough to call these antigens unique (to lung tumors)." he says. But he cites the "remarkable" three-shot regimen and the immune-response-monitoring aspects of the work as significant.

Although Rauscher admits he is "nervous" about the study, he says he believes the results are valid "until proven otherwise" and that "an awful lot of other cancers may be amendable (to this approach)." For decades researchers have been looking at tumor-associated antigens as possible cancer markers and as signposts to better therapy, without the dramatic results reported this week However, even if the new antigen were to enter the commercial-production pipe-line soon, says Rauscher, it likely would be five to seven years before it would be widely available.