Training the immune system to fight leukemia found to be effective

Reprogramming T cells from patients' bodies had a positive effect on the progress of leukemia in more than half of participants in a study.

By Stephen Feller

PHILADELPHIA, Sept. 3 (UPI) -- Personalized reprogramming of T cells as part of treatment for chronic lymphocytic leukemia resulted in at least a handful of patients maintaining complete remission of the disease for nearly five years, according to a new study from the University of Pennsylvania.

Patients in the study were shown to still have modified cells in their systems, leading researchers to believe the treatment, called CTL109, not only worked to eliminate cancer, but offered long-term protection against its return.


All of the leukemia patients who participated in the study had previously relapsed or seen their cancer continue to progress while receiving standard cancer treatments, researchers said.

"The durability of the remissions we have observed in this study are remarkable and have given us great hope that personalized cell therapies are going to be important options for patients whose cancers are no longer treatable with standard approaches," said Dr. David Porter, a professor at the University of Pennsylvania, in a press release. "The patients in this study are pioneers, whose participation has given us a foundation of knowledge and experience on which to build this new approach to help more patients."


Researchers collected T cells from 14 leukemia patients using a procedure similar to dialysis, reprogramming the cells to hunt and kill cancer using an antibody-like protein known as a chimeric antigen receptor, or CAR, which targets a protein on the surface of cancerous cells associated with leukemia. Once patients had undergone lymphodepleting chemotherapy, researchers injected the altered cells back into their bodies.

Previous studies have shown that CAR causes serious instances of cytokine release syndrome, or CRS, which carries flu-like symptoms and can lead to serious, life-threatening toxicity. The researchers crafted a treatment plan because they already were aware of this. All 14 patients in the study developed CRS but recovered.

Researchers reported that four patients in the study saw their leukemia go into complete remission. Although one of the four died during surgery to remove a carcinoma on his leg, the other three remain in remission 28, 52 and 53 months after being treated with CTL109.

Four other patients' cancers responded partially to the treatment, however two died after their leukemia continued to progress, one died of a pulmonary embolism six months after receiving CTL109, and the other is alive while receiving other, additional treatments after the CTL109.

CTL109 had no effect on the other 6 patients in the study.


The study is published in Science Translational Medicine.

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