Scientists for the first time have genetically modified tumor-fighting immune cells, allowing patients to rid themselves of an aggressive form of cancer, according to a study released Thursday.
The technique, used to cure two patients with advanced melanoma, paves the way for a new approach to fighting cancer by harnessing -- and boosting -- the body's own immune system instead of relying on toxic chemotherapy and radiation treatments to kill out-of-control tumors.
The researchers from the National Cancer Institute, whose findings were published online by the journal Science, say the strategy could be adapted to treat breast, prostate, lung, colorectal and other common cancers.
"It's obviously very exciting," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, who was not involved in the research. "It's a proof of concept of being able to develop a technique where they can use a patient's own blood cells to fight cancer."
Dr. Steven A. Rosenberg, chief of the National Cancer Institute's surgery branch and senior author of the study, said the results reaffirm the promise of gene therapy after several high-profile setbacks.
Rosenberg and others cautioned that it would take several years to translate this initial success into a practical therapy.
They added that there is still more failure than success with the technique. Fifteen other melanoma patients enrolled in the study failed to show sustained improvement from the modified immune cells. Twelve of those patients have died, and the other three are near death, Rosenberg said.
But the success with two patients, who are cancer-free more than a year and a half after their treatment, was enough to demonstrate the possibility of a new front in the war against cancer.
"The important thing is this approach worked," said Dr. Margaret Kemeny, director of the Queens Cancer Center of Queens Hospital in New York. "Can they make this approach work more often? That is the question."
Melanoma accounts for only 4% of skin cancer cases, but it is the most lethal type. More than 62,000 patients will be diagnosed with melanoma this year, and 7,910 people will die from it, according to estimates from the American Cancer Society.
Rosenberg had previously discovered that some melanoma patients are able to generate a type of immune cell, called a T cell, that recognizes the tumor cells as unwanted intruders and attacks them.
