About 35% of non-small-cell lung cancers (NSCLC) have this protein, which is also present in some melanomas and head and neck cancers.
In a trial of early-stage lung cancer patients whose tumors expressed MAGE-A3, treatment with the vaccine was shown to reduce the risk of relapse after surgery.
Long-term follow-up results from the early trial of the immunotherapy were presented at the 1st European Lung Cancer conference in Geneva, Switzerland.
"The principle behind this approach has potential for many different types of cancer," researcher Johan Vansteenkiste, MD, PhD, tells WebMD. "The principle is that you teach the patient's immune system to eliminate cancer cells that express certain proteins."
The vaccine therapy has not been compared head-to-head with chemotherapy, which is often given to surgically treated lung cancer patients to reduce their risk of relapse.
But Vansteenkiste says the immunotherapy-treated patients in the phase II study had outcomes similar to those seen among chemotherapy-treated patients, with almost no side effects.
"Many surgically treated lung cancer patients are not able to tolerate the side effects of chemotherapy, either because of their age or because of other health issues," he says. "This approach is a promising alternative."
A total of 182 patients with NSCLC were included in the early study, sponsored by drugmaker GlaxoSmithKline, which is developing the vaccine therapy. All the patients had cancers that expressed MAGE-A3.
After having surgery to remove their tumors, 122 patients were randomly assigned to treatment with the MAGE-A3-targeting vaccine and 60 patients got placebo vaccines.
The patients were given five injections every three weeks at the beginning of treatment and then eight injections every three months later on for a total of 27 months, Vansteenkiste says.
After 44 months of follow-up, 69 of the 182 patients had cancer recurrences, including 57 deaths. The researchers report that the treatment was well-tolerated. The MAGE-A3-treated patients seemed less likely to have recurrences and die from their disease than the placebo-treated patients, although this is being further evaluated in an ongoing phase III study for efficacy.
Immunotherapy vs. Chemotherapy
This year in the U.S., 215,000 new cases of lung cancer will be diagnosed and close to 162,000 people will die from the disease, according to National Cancer Institute projections.
Surgery is the standard treatment for patients with early-stage disease, but about 50% of patients who have surgery end up dying of their lung cancer, Vansteenkiste says.
He says adding chemotherapy to surgery boosts the survival rate by about 10%, a rate similar to that seen in the MAGE-A3 trial.
Last year, GlaxoSmithKline began recruitment for a phase III study of the cancer vaccine, which will include more than 2,000 patients whose cancers express MAGE-A3.
The placebo-controlled trial will include patients treated with the vaccine both instead of and in addition to chemotherapy.
"We want to see if there is an extra benefit to adding the immunotherapy to chemotherapy," he says.
Len Lichtenfeld, MD, of the American Cancer Center, tells WebMD that it remains to be seen if the MAGE-A3 vaccine will prove to be a useful treatment for lung cancer.
"The study suggests that there may be some benefit here, but clearly a larger trial will tell us more," he tells WebMD.
He adds that it will not be clear if the immunotherapy works as well as chemotherapy until the two treatments are compared head-to-head.
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