Metastatic melanoma cells

What's the News: Souped-up cells from a patient's own immune system could one day be used to treat advanced melanoma, according to a preliminary study

published in Science Translational Medicine investigating the safety of the technique. The researchers manipulated a patient's immune system cells to better recognize cancer cells in the lab and then re-introduced those cells into the body---an approach called "adoptive T-cell therapy." How the Heck:

The researchers took T-cells, one of the main classes of cells the immune system uses to fight off disease, from nine patients with advanced melanoma.

Using genetically engineered cells that have some of the same antigens---the sorts of molecules that immune cells take as a signal to attack---that tumor cells do, the researchers in effect improved the T-cells' memory for cancer cells.

They then multiplied the cells, so they'd be more numerous inside the body, and infused each patient with their own cells. This infusion of souped-up cancer-targeting cells boosts the immune system's ability to combat the cancer.

Ten weeks later, seven of the patients had more of the specially trained T-cells than were originally re-introduced. Of the nine patients in total, the cancer stabilized in four of them---not getting better but not getting worse, either---and the cancer disappeared altogether in one patient. (Two years later, there is no sign of that patient's cancer returning.)

Five of those patients later took ipilimumab, a common melanoma-fighting drug, and had better responses than would normally be expected---suggesting adoptive T-cell therapy might also improve the efficacy of current drug treatments.

What's the Context:

Chemotherapy---the usual treatment for melanoma---comes with severe side effects; adoptive T-cell therapy, if successful, would provide a way to fight the disease without having to put the patient through the ordeal of chemotherapy treatments.

Many previous studies of adoptive therapy have either failed, as the lab-trained T-cells died off too quickly when returned to the body, or required the use of other treatments, which come with their own set of side effects, to help those T-cells survive.

Not So Fast:

The study was Phase I trial---which primarily tests the safety of a treatment---with a small number of people enrolled. Many more tests need to be done, with many more patients, to investigate how effective this technique is before it's ready for the clinic.

The Future Holds:

If this technique proves effective in fighting melanoma, it's likely it could also be used to battle other cancers. "Cancer-killing T-cells trained in the lab can induce long-lasting anti-cancer effects," Dr. Marcus Butler, the study's lead researcher, told the BBC. "The dream would be that we could make a library of killer T-cells that we could generate quickly for patients."

Reference: Marcus O. Butler et al. "Establishment of Antitumor Memory in Humans Using in Vitro–Educated CD8 ^+ T Cells." Science Translational Medicine, April 27, 2011. DOI:10.1126/scitranslmed.3002207

Image: National Human Genome Research Institute