LONDON, Nov. 6 (UPI) -- Doctors cleared a 1-year-old of an aggressive form of leukemia using an experimental treatment that had previously only been tested in mice, which researchers said could be a "huge" step forward in treating leukemia and other cancers.
The girl, named Layla, had relapsed acute lymphoblastic leukaemia, or ALL, and already been treated with chemotherapy and a bone marrow transplant, as well as another experimental treatment -- none of which kept the cancer from getting worse.
At the point doctors were beginning to recommend palliative care because they were out of options, Layla's parents were told about experimental work being done on genetically-edited immune cells at the hospital where she was being treated.
"The approach was looking incredibly successful in laboratory studies, and so when I heard there were no options left for treating this child's disease, I thought 'why don't we use the new UCART19 cells?'' said Dr. Waseem Qasim, a professor of cell and gene therapy at University College London, in a press release. "The treatment was highly experimental and we had to get special permissions, but she appeared ideally suited for this type of approach."
Layla was diagnosed with ALL at 14 weeks old -- doctors called it "one of the most aggressive" forms of the disease they'd ever seen -- starting several rounds of chemotherapy and a bone marrow transplant almost immediately. The disease returned seven weeks later.
After trying another experimental treatment, doctors suggested moving Layla to palliative care unless her parents were open to trying UCART19, modified T-cells that are genetically reprogrammed to target and kill leukemia cells.
Once doctors received special clearance to use the cells with Layla, because they'd only been tested with mice, they gave her 1 ml of UCART19 intravenously. Several weeks passed before doctors saw an immune response, in Layla's case in the form of a rash, which meant the treatment was working.
"As this was the first time that the treatment had been used, we didn't know if or when it would work and so we were over the moon when it did," said Dr. Paul Veys, director of bone marrow transplants at Great Ormond Street Hospital and Layla's lead doctor. "Her leukemia was so aggressive that such a response is almost a miracle."
The company developing UCART19, Cellectis, said in a press release it would accelerate its clinical development after the success with Layla.
Doctors caution that, in addition to further tests with more human patients, a long-term view of Layla's health will also help show how effective UCART19 is, especially considering her history of relapse.
An account of Layla's case is published in Nature.