The National Cancer Institute scientists tried out their method on 17 patients in three groups, injecting them with their own lymphocytes, or white blood cells, altered by the genetic introduction of T-cell receptors which then steer the cells to find and destroy cancer tumour cells.
The method failed to stall the disease in the first group of three, so the researchers modified the treatment to make sure the modified white blood cells were injected into the patients at the cells’ most active growth phase.
That generated better results, of the remaining 14 patients the regressed in two patients who have remained free of the highly dangerous, and frequently fatal form of cancer, for one year.
Moreover, one month after receiving the gene therapy, all patients in the latter two groups continued to have significant levels of the cancer-fighting cells.
"These results represent the first time gene therapy has been used successfully to treat cancer," said Elias Zerhouni, director of the National Institutes of Health, which oversees the National Cancer Institute.
"We hope is will be applicable not only to melanoma, but also for a broad range of common cancers, such as breast and lung cancer," he said.