Early Leukemia Treatment Shows Promise
RENEE MONTAGNE, host:
Here's a story of success treating cancer with an approach that involves genetically modifying the patient's own cells. Researchers are reporting on the treatment of a handful of patients with leukemia. It's the latest sign that gene therapy may finally be achieving some of the promise its proponents have been touting for 20 years. NPR's Joe Palca reports.
JOE PALCA: There's something beguiling about the idea of gene therapy. Broken genes are known to cause diseases, so fix the gene and cure the disease. That turned out to be a lot easier to say than to accomplish.�But others have been tinkering with the notion of adding new genes to patients' own cells - genes that can help treat diseases.
That's the approach David Porter and his colleagues at the University of Pennsylvania are pursuing. They work with T-cells. These are immune cells crucial for killing invading organisms. But T-cells don't typically attack cancer cells because they don't see them as invaders.�
Porter took cells from patients with a cancer called Chronic Lymphocytic Leukemia and genetically modified them in the lab.
Dr. DAVID PORTER (University of Pennsylvania): The genetic modification is intended to make the T-cells recognize and target the patient's leukemia cells.
PALCA: He then put the modified cells back into the patients.�
For the three patients in the study, the gene therapy was a last resort. None of the therapies doctors had tried on them had worked. But Porter says the gene therapy worked. Two of the three got completely better, and the third improved.
Reports on this treatment appear in the journal Science Translational Medicine and The New England Journal of Medicine.
This is not the first time genetically modified T-cells have been used in patients.
Dr. PORTER: Big limitations have been when these T-cells have been given, they don't survive long in the body, and they don't proliferate, they don't grow or expand in the body.
PALCA: In this case the cells were still going strong at six months. And that means if cancer cells reappear, the T-cells will be there to knock them off.�
There are several caveats to keep in mind. For example, it's not clear how long the treatment will continue to work. It's also not clear if it will work for everyone with leukemia.�But Michel Sadelain of Memorial Sloan Kettering Cancer Center says several teams, including his, are pursuing similar approaches. He says the Pennsylvania team's preliminary success is good news.
Dr. MICHEL SADELAIN (Memorial Sloan Kettering Cancer Center): I think what it signals is that we're entering a very exciting phase of clinical research.
PALCA: So we say at this point promising but not ready for routine therapy.
Dr. SADELAIN: No, definitely not.
PALCA: Still, even a modest success after two decades of work is extremely gratifying.�
Joe Palca, NPR News, Washington.
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