‘Designer cells’ fight leukaemia in baby girl

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A one-year-old girl with life-threatening leukaemia has become the first in the world to be treated with ‘designer’ immune cells, genetically modified to attack her cancer. A specialist team, lead by Professor Paul Veys at Great Ormond Street Hospital (GOSH), stressed that it could be many months before it is clear whether the cancer has been merely delayed or eradicated entirely.

Layla Richards was diagnosed aged just 14 weeks, after developing a fast heart beat and rejecting her milk. Doctors initially suspected a harmless stomach bug, but further tests revealed cancerous cells had developed in her bloodstream. Suffering from a particularly aggressive form of cancer, called acute lymphoblastic leukaemia (ALL), Layla was rushed to intensive care where she began chemotherapy.

In acute lymphoblastic leukemia, immature cancerous white blood cells, known as lymphoblasts, are produced.
In acute lymphoblastic leukaemia, immature cancerous white blood cells, known as lymphoblasts, are produced.

Though more common forms of leukaemia are easier to treat, only 25% of children survive ALL – and doctors described this case as the most persistent they had ever seen. Even after seven weeks of intensive chemotherapy and bone marrow transplants (to replace lost blood cells), the cancer showed no signs of abating. At this point, doctors at GOSH suggested that Layla’s parents start looking into palliative care options, with a cure appearing unlikely. Undeterred, Layla’s parents demanded that the doctors continue treating their daughter.

In conjunction with GOSH, researchers at UCL had demonstrated recently that genetically modified cells, called UCART19, could be used to target leukaemia – but trials had only taken place in rats, not humans. To treat Layla with the cells, of which there remained only one 1ml vial, required petitioning an emergency ethics committee. It was not clear whether the treatment would have any effect.

The UCART19 came from a batch of donated T-cells, which play a central role in human immunity to disease and infection. The researchers used enzymes to insert a gene into the T-cells’ DNA which would help them to target and kill cancerous cells. Similarly, they removed genes which otherwise would make the cells visible to an immunosuppressant drug, alemtuzumab. In doing so they effectively allowed the T-cells to operate undetected.

For the treatment to proceed, the doctors needed Layla’s parents’ informed consent. Her mother, Lisa Foley, 27, asked the doctors to “try anything for our daughter, even if it hadn’t been tried before.” She insisted she and her partner did not want to “give up on [their] daughter.”

Within two weeks of the transfusion taking place, Layla developed a rash – a sign that the treatment was taking effect and that her body was fighting the leukaemia. Two months following, Layla was given a bone marrow transplant to replace that which had been damaged by the treatment; a month after that she was able to return home.

Doctors at GOSH hope this gene-editing technique could be used to fight many other forms of cancer, and are beginning clinical trials in the hope that Layla’s response can be replicated in others. Dr Matt Kaiser, Head of Research at cancer charity Bloodwise, said that even though the technique was in the earlier stages of its development, it may hopefully one day “provide a lifetime cure for these children.”

Photograph: Bobjgalindo via Wikimedia Commons

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