Last year, his team reported the first promising results in five adult patients who achieved remission after the therapy.
He estimated that between 60 and 80 people in the United States have since entered experimental trials of the new treatment, which is also being studied in Europe.
Not a Fluke
In December 2013, experts from multiple US centers where trials are ongoing presented their findings at the American Society of Hematology (ASH) annual meeting, including the University of Pennsylvania, which is also studying the approach in adults with chronic lymphocytic leukemia (CLL).
The Children's Hospital of Philadelphia is enrolling pediatric patients in trials of T-cell therapy. Brentjens said other US centers have shown similar remission rates in their studies so far, "demonstrating that this isn't a fluke."
"This is a real phenomenon," he told AFP. "This could be a paradigm shift in the way we approach cancer therapy."
Kanti Rai, chief of the CLL Research and Treatment Program at North Shore-LIJ Health System in New York, described the latest study as "a major service to all of us."
Rai, who was not involved in the research, noted that it has been a few years since scientists first reported on their initial success against CLL. "In the present report, we are told that equally dramatic and excellent results were obtained when a more frightening and fatal disease, such as adult ALL was the enemy," said Rai.
Researchers are still trying to figure out why it does not work in all patients. Efforts are also ongoing to identify cancer-specific receptor cells that could allow the technique to tackle other types of tumors.
"The expansion to other kinds of cancers is next on the to-do list," said Brentjens.
In the meantime, the therapy remains expensive, costing around $100,000 per patient, a price tag experts believe will come down once pharmaceutical companies get more involved and the technique becomes more widespread.