Six of seven advanced melanoma patients had a positive response to an experimental vaccine, a finding that shows promise for personalized skin cancer treatment, researchers report.
The vaccine also slowed tumor progression in three of the patients, according to the investigators at the Washington University School of Medicine in St. Louis.
This cutting-edge approach -- considered by many the future of cancer treatment -- uses a patient's own cells to enhance an immune response to the attacking cancer cells and slow their growth, the study authors explained.
"This is personalized immunotherapy," said senior researcher Dr. Gerald Linette, an associate professor of medicine and neurosurgery.
Melanoma is the deadliest of skin cancers. Each year in the United States more than 76,000 cases of melanoma are diagnosed, and nearly 10,000 die from the disease, according to the U.S. National Cancer Institute.
The immune system plays a part in melanoma, Linette said, and the researchers wanted to see if a molecule called interleukin 12p70 could mount an immune response against the cancer.
"The results show that, in fact, interleukin 12p70 was very important in controlling the disease," he said. "It promoted a response where T cells of the immune system act directly against the melanoma."
Some patients make a lot of interleukin 12p70, and those are the patients who did well. But some patients make very little or no interleukin 12p70, and those are the patients who did worse, Linette said. For those patients, another way of enhancing the response will have to be tried, he said.
The study, published online July 11 in the Journal of Clinical Investigation, discusses use of the vaccine on seven patients with recently diagnosed stage IV cancer, meaning the cancer had spread to other areas of the body.
Dr. Michele Green, a dermatologist at Lenox Hill Hospital in New York City, said, "This is a great first step."
Techniques such as this will be standard some day, she believes. "We are at the infancy of this, but this is going to end up being the way we cure cancer," Green added.
Currently, the prognosis is bleak for late-stage melanoma, Green noted. "If you have advanced melanoma, there is no treatment," she said.
The experimental vaccine is made from a patient's dendritic cells, which is a type of immune cell. The researchers modified the cells to increase production of interleukin 12p70, which stimulates a robust immune response to the cancer, Linette explained.
The research team was able to activate these dendritic cells before giving them back to the patient, he said.
The vaccine seems safer than earlier attempts, but it will be years before such an approach might be put into practice. For now, no clinical trials are planned, Linette said.
"Scientists have been testing vaccines in cancer patients for about 15 years, and the results have been rather discouraging," Linette added. "It's going to take at least five to 10 years more testing before scientists agree what's the best dendritic cell vaccine."