But as the researchers treat more patients, they can follow those who are ineligible for a bone marrow transplant and see how they fare after the immunotherapy alone.
Sadelain said that it's possible that the T-cell therapy might need to be repeated.
Safety questions exist as well. "The risk of this therapy would be creating an overwhelming immune response," Sadelain said. That could lead to extremely high fever or other potentially life-threatening effects.
In this study, funded by the cancer institute, two patients had signs of an overly strong immune response. But it was manageable with anti-inflammatory steroid drugs, Sadelain added.
Another expert, Richard Winneker, senior vice president of research for the Leukemia & Lymphoma Society, said he was encouraged by the results. "And this should certainly stimulate further work," he said.
The leukemia society has funded Penn's work on adoptive T-cell therapy, and Winneker said, "We're thrilled to see this field showing positive results."
Brentjens and Sadelain hold a patent on the CAR used in the therapy.
Learn more about adult ALL from the American Cancer Society.
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