Treatment of Leukemia
Scientists are reporting very preliminary success with a new approach for treating leukemia — turning the patients’ own blood cells into assassins that hunt and destroy their cancer cells.
So far, researchers have treated three patients with chronic lymphocytic leukemia, and their published paper reports the results for one of them. The patient had initially responded to chemotherapy but relapsed, leaving him only one option, a risky bone marrow transplant. So far, the researchers say, that patient and another leukemia patient appear cancer-free up to a year after treatment. The third patient improved but still has some cancer.
Papers describing the work were published Wednesday in The New England Journal of Medicine and Science Translational Medicine.
But an editorial in The New England Journal of Medicine urged caution, pointing out that there were complications with the therapy and that it was too soon to assess its effectiveness.
“Only with the more widespread use of” the therapy “will we learn whether the results reported by Porter et al. reflect an authentic advance toward a clinically applicable and effective therapy or yet another promising lead that runs into a barrier that cannot be easily overcome,” wrote the editorialists, Dr. Walter J. Urba of the Providence Cancer Center in Portland, Ore., and Dr. Dan L. Longo, a deputy editor at The New England Journal of Medicine.
But the study’s lead researcher, Dr. Carl June, was optimistic.
“It worked great; we were surprised it worked as well as it did,” said Dr. June, a gene therapy expert at the University of Pennsylvania. “We’re just a year out now. We need to find out how long these remissions last.”
Dr. June and his colleagues used a novel carrier to deliver the new genes into patients’ white blood cells — T cells — and added a signaling mechanism telling the T cells to kill and multiply.
The treatment had a potentially serious side effect, however. It depleted patients’ antibody producing cells, their B cells. That was, the investigators wrote, “an expected chronic toxic side effect.”
And, Dr. Urba said, “it’s still just three patients,” adding, “Three’s better than one, but it’s not 100.”
What happens long-term is key, he said: “What’s it like a year from now, two years from now, for these patients.”
Posted by j0k0gbj