The patient was dying of leukemia. One hundred and seventy of 0 cells in his bone marrow had a mutation causing cancer, and her lymph nodes were swollen, a sign that the cancer was deteriorating. He had already been on several courses of chemotherapy, but the disease has shown some signs of improvement. Then, in July 2010, he is enrolled in a clinical trial for an experimental treatment designed to transform its own immune cells against the cancer. A few months later, all signs of leukemia were gone, his doctors report today.
"The surprise was how it worked to clear both tumor so quickly," said immunologist Bruce Levine of the University of Pennsylvania, one of the scientists who created the new treatment.
cancer treatment, described today in two papers in Science Translational Medicine and the New England Journal of Medicine , is based on the idea that the human body has already begun to fight against the abnormal cells, dangerous. T cells, the first line of defense of the immune system recognize cells that are not part of the body, such as bacteria and triggered a cascade of events to kill them. scientists studying cancer have long been struggling with how to do these T cells kill tumor cells. But they never found the perfect combination of factors to transform the T cells of cancer killers .
Levine and his colleagues designed a new gene that can be inserted into the T cells to induce them to attack cancerous B cells, the cause of chronic lymphocytic leukemia (CLL). The new gene encodes a receptor that, at one end, can bind to a molecule which is unique to cancer cells B. The other end of the receptor triggers a chain reaction when such B cell is bound, eventually leading to the T-cell to destroy cancer cells. "Essentially, we convert T cells which normally recognize other types of cells to be tumor-specific," said Levin.
In the initial clinical trial, the researchers tested their method in three patients with CLL. They took a T cell sample of each patient and the novel gene added to the cells, using the same operating method and the novel gene in each case, while retaining the T-cells from each individual patient. Once the T cells contain new specific receptors of the tumor, scientists have infused T cells back into the blood of each patient.
The three patients are now in remission. On average, T cells modified killed about one kilogram of tumor cells in each patient. Each cell modified T infused into the patient's blood, the cells at least 1000 tumor were killed, which led researchers to copy the T cells "serial killers." In addition, after 12 months, blood tests revealed patients still had copies of the modified T cells circulating in their blood capable of killing cancer cells. And although the data only covers one year, Levine said that the effects are probably even longer.
"the power of these T cells," Levine said, "is that you should not continue to give them as you do with chemotherapy drugs. They are a dynamic, living, dividing the drug, and can be administered once and they survive and multiply, continuing to protect against cancer. "
The new therapy is not only a potential boon for CLL patients, says oncologist Walter Urba of the Providence Cancer Center in Portland, Oregon. The success of the clinical trial could lead to other types of cancer. "Now you can try to change this receiver to recognize a different target," said Urba, who specializes in cancer immunotherapy. "Let's make a specific receptor breast cancer, and prostate cancer-specific receptor, and a receiver specific to colon cancer. The potential is enormous for application to different tumor types. "
And Urba warns that the current findings are based on a small sample size. More work is needed to verify that the treatment is largely successful in all CLL patients and that stray cancer cells will eventually mutate not they avoid the display of the target molecule by T cells
"This is really exciting," he said. "The results are very promising. But it is also important to remember that this is just a couple of patients and they were followed only for a short time. We need to see more studies now."
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