An experimental therapy known as immunotherapy has shown promise in treating patients with non-Hodgkin lymphoma, a blood cancer that affects the lymph system, U.S. researchers said Wednesday.
The study, published in the U.S. journal Science Translational Medicine, involved using patients' own immune cells, which were taken out, modified and then injected back to hunt and kill cancer cells.
In the trial, 32 participants, who have previously exhausted multiple conventional cancer treatments, received an infusion of the so-called CAR T cells following chemotherapy that was given to make space in the patients' bodies for the infused cells.
The researchers found that the CAR T cells most effectively knocked out the cancer in a group of 11 patients who received a two-drug combination chemo followed by an intermediate dose of the engineered T cells.
Seven of these participants, or 64 percent, went into complete remission, they said.
Overall, among all 20 patients who received the two-drug chemo regimen, half of them achieved a complete remission.
Of the remaining 12 patients who received different chemotherapy, only one went into complete remission after CAR T-cell infusion.
The CAR T cell therapy involves modifying disease-fighting T cells extracted from patients' bloodstreams to allow them to contain a synthetic, cancer-targeting chimeric antigen receptor in their genomes.
When the modified T cells were intravenously transferred back into the patients, they can target a molecule called CD19 that is found on the surface of certain white blood cells, including some types of lymphoma cells.
There are several ongoing trials of CAR T cells in the U.S., and this study's hallmark is its use of a one-to-one ratio of helper and killer CAR T cells, which join forces to kill CD19-positive tumor cells, said Cameron Turtle, an immunotherapy researcher at Fred Hutchinson Cancer Research Center and one of the study leaders.
"The main message is that you can treat patients with non-Hodgkin's lymphoma with CAR T cells and get very good response rates with optimization of the CAR T-cell dose and lymphodepletion (chemotherapy)," said Turtle.
