White blood cells specially trained to kill tumors work… but they tend to fade away quickly when re-injected into cancer patients.
Scientists have now found a way to keep immune cells in the bloodstream for well over a year, improving therapy for late-stage melanoma.
If detected and removed at an early stage, these skin cancers can usually be cured, but once the disease has spread to distant sites, survival time can be less than a year.
Called adoptive T cell therapy, the current technique works like so: Doctors pluck out T cells from a patient’s immune system. Then they train them in the lab to recognize and destroy tumor cells. When those professionally trained cells are infused back into the patient, they help boost the nature immune system.
But the success of this technique depends on the T cells’ ability to remember to fight cancer in the long term. And unfortunately, once in patients, these anti-tumor T cells are rather fleeting (unless they’re further treated, though this usually comes with toxic side effects).
So Marcus Butler of Dana-Farber Cancer Institute and colleagues show that T cell memory can be established outside the body – by training them using a special type of cell called an artificial antigen-presenting cell. (Like wanted posters, these inform the immune system that a cancer is present and must be eliminated.)
- The team created antigen-presenting cells that were able to transform regular T cells into ‘educated’ memory T cells that attack tumor cells and survive for a long time.
- Then they performed a phase I clinical study with 9 advanced-stage melanoma patients to see if the memory T cells actually hang around long enough after infusion to be beneficial.
While the T cells survived for a long time, the treatment mostly just stabilized the disease… except in one patient, who is now disease-free. (Pictured, pre-infusion on left, day 140 on right.)
Many of the patients did, however, benefit from receiving a newly FDA-approved drug – ipilimumab – along with the memory T cells.
"Cancer-killing T-cells trained in the lab can induce long-lasting anti-cancer effects,” Butler says. “The dream would be that we could make a library of killer T-cells that we could generate quickly for patients."
The study was published in Science Translational Medicine yesterday.
Image: Butler et al.