Experimental Therapy Beats Back One Patient's Melanoma

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Similar happenings have been recorded for other types of cancer.

"Maybe there were 10 cells in the body that were very good, sort of a smart bomb against the melanoma, but they weren't enough," Trisal explained. "The bee sting or poison ivy multiplied these smart bombs one thousand times so suddenly this army of 10 became an army of a billion."

And that is essentially what the authors of the new study did, collecting CD4+ T-cells from nine melanoma patients, isolating single cells that they believed would target a certain protein on the tumor cells, cultivating and enriching these cells, and then re-infusing them into the patient.

Patient Four, a 52-year-old man, received five billion cloned CD4+ T cells designed to go after the melanoma-associated NY-ESO-1 antigen. The new cells stayed in the patient's body for 80 days. Two months later, the man's melanoma was gone.

The man received a higher dose than the first three patients but the same or lower dose than the subsequent five patients. The first three had no response at all while the later patients saw some response, but none as dramatic as Patient Four.

"We don't know why he was the lucky one," Yee said. "Maybe it was something specific to him or his tumor. Maybe he had a low-level pre-existing response that we were able to augment."

And therein lies a major problem with immunotherapy as it exists now. "We know this works but it's a shot in the dark," Trisal said. "It works maybe in one in 100 people instead of one in 1,000 where the body itself fights the cancer."

The question is how to make the process more efficient and effective.

"Obviously there's a lot of promise for immunotherapy of this kind but I think that we're several years away from making this any kind of standard therapy," Yee said. At this point, the therapy needs to be standardized to the patient and it can take months to grow the required cells, during which time the patient's condition could deteriorate dramatically.

"It would be helpful to try to streamline the process," Yee said. "[Right now], we can only target a small fraction of patients. What we're looking for in the future is to streamline this process and decrease the time it takes to grow cells and to see if we can target other antigens. This is a proof of principle: Yes, we can use CD4+ clones."

More information

Visit the American Cancer Society for more on immunotherapy.