Immune Therapy Found to Fight Advanced Skin Cancer
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Immune Therapy Found to Fight Advanced Skin Cancer Thu Sep 19, 5:49 PM ET By Amy Norton NEW YORK (Reuters Health) - An immune-system therapy that boosts critical cancer-fighting T cells has been found to shrink tumors in some patients with advanced malignant melanoma, the deadliest form of skin cancer. The small study by researchers at the US National Institutes of Health. His team found that of the 13 treated patients, whose melanoma had spread to distant sites such as the lungs and liver, six saw their tumors shrink by at least half. In another four, some tumors regressed while others did not. The findings were published Thursday in Sciencexpress, the online edition of the journal Science. In an interview with Reuters Health, Rosenberg stressed that this T cell-based therapy is still "highly experimental" and, for now, only applicable to malignant melanoma. "But we hope to extend it to others cancers," he said. Malignant melanoma, although curable when caught early, is responsible for the majority of skin cancer deaths. The patients in the current study all had advanced melanoma that had failed to respond to standard therapy. The experimental therapy Rosenberg's team used takes advantage of the natural cancer-fighting work of "killer" T cells, which are able to knock off cancerous, infected or foreign cells. Many scientists have been studying ways to enhance this natural defense in cancer treatment. But in melanoma research, vaccines designed to boost patients' T cells have so far failed to shrink tumors. And in past attempts at multiplying patients' T cells then transferring them back, the transferred cells have failed to take hold in the body. To try to get past this problem, Rosenberg's team gave patients chemotherapy to deplete their immune systems before transferring their T cells back. From each patient, the researchers had removed and multiplied only some select T cells known to be active against their melanoma. After treatment, six patients showed a clear response, two of whom had a regression of more than 95% of their disease. Blood samples from these two patients also showed that the transferred melanoma-fighting T cells had "repopulated" their immune systems, according to the researchers. SOURCE: Sciencexpress 2002;10.1126/science.1076514. By Maggie Fox, Health and Science Correspondent WASHINGTON (Reuters) - Ten of the most desperate skin cancer patients have had their tumors either stopped, or nearly destroyed, by a new treatment that involves replacing virtually their entire immune systems with specially targeted killer cells, U.S. researchers said on Thursday. Although the treatment failed completely in three patients, those who responded had few side effects and several were able to go back to work or school, said Dr. Steven Rosenberg of the National Cancer Institute, who led the study. "Here we are trying to take advantage of the body's own natural defenses," Rosenberg told a seminar sponsored by the American Medical Association. His team experimented on 13 advanced melanoma patients. Melanoma, which affects some 50,000 Americans a year, is easily treated if caught early but is deadly if not. Some of the patients probably only had months to live, despite having undergone surgery, chemotherapy and treatment with the hormone interleukin to stimulate the immune system, Rosenberg said. Rosenberg wanted to see if there was a way to use some of the body's own immune system cells to destroy the cancer. "The body recognizes the cancer as foreign, but not foreign enough to reject it," Rosenberg said. So they took out little pieces of each patient's tumor and checked for lymphocytes -- immune system cells -- that were actually attacking the tumor cells. They grew these in the laboratory and looked to see which ones were the most active against the tumor. They then used drugs to virtually destroy each patient's own immune system. Often doctors do something similar to treat leukemia -- destroying the bone marrow, where the immune cells are produced, and replacing it with bone marrow from a donor. The NCI technique, described in Friday's issue of the journal Science, was different. INFUSION OF KILLER CELLS They replaced the destroyed immune system with the cells that had been found to be most active against the tumor cells. All it took was a 20-minute intravenous infusion. These cells thrived in the patients, Rosenberg said. "Not only do you get the large numbers, but they stay there," Rosenberg said. In one of the patients, 97 percent of the lymphocytes specifically targeted the cancer cells, and they can last for as long as five months, he said. One 16-year-old boy had a tumor that started on his knee and spread through his body, despite treatment. "He had a volleyball-sized tumor in his pelvis. He was on round-the clock narcotics," Rosenberg said. "I would guess his life expectancy was a couple of months. The patient, two years later, is completely disease-free." Rosenberg was also pleased to find that the patients' immune systems seemed to have recovered fully from the treatment. Two patients contracted infections while undergoing the therapy, but they survived with treatment. The worst side effect seems to be an auto-immune effect -- the cancer-killing cells also turned against the cells that give the skin and eyes their color. One patient developed an eye inflammation and others developed patches of white skin. Rosenberg warns the treatment is highly experimental and will not be available for years. "Some patients have not responded at all," he warned. Nonetheless, he hopes it can be used against a range of cancers, including breast, prostate and ovarian cancers. "This is earth-shattering," said Dr. Nancy Nielsen, an internist in Buffalo, New York who is also a member of the AMA board. She predicted desperate cancer patients would bombard the NCI with queries.
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