Designer immune cells used to treat ‘incurable’ leukaemia case

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A treatment that uses “molecular scissors” to edit genes has been used for the first time by UK medics successfully to treat a one-year-old girl with an “incurable” form of leukaemia.

The case at Great Ormond Street Hospital in London involved the creation of “designer immune cells” programmed to hunt and kill the disease. The girl, called Layla, is now cancer free and doing well, according to the hospital.

The breakthrough will add to excitement over the fast-emerging field of gene-editing — a type of genetic engineering in which DNA is inserted, replaced or removed from genes to fix faults or fight disease.

Gene-editing has caused controversy because of its potential to be used in ethically dubious ways, such as the creation of “designer babies”. However, the London success helps show why many scientists are so enthusiastic about the technology.

The so-called UCART19 cells used at Great Ormond Street had shown promise in animals but had never been used in humans before they were administered as a last-ditch attempt to save Layla after other drugs failed.

“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 Waseem Qasim, professor of cell and gene therapy at University College London’s Institute of Child Health.

The treatment, developed by a French biotech company called Cellectis, consisted of 1ml of UCART19 cells injected into Layla’s bloodstream. After several weeks it was clear the leukaemia cells were disappearing.

“We didn’t know if or when it would work and so we were over the moon when it did,” said Paul Veys, director of bone marrow transplant at Great Ormond Street. “Her leukaemia was so aggressive that such a response is almost a miracle.”

We didn’t know if or when it would work and so we were over the moon when it did. Her leukaemia was so aggressive that such a response is almost a miracle

– Professor Paul Veys

The treatment is similar to cancer therapies in development using modified T-cells from companies including Novartis of Switzerland and Juno and Kite of the US. However, whereas others use cells extracted from the patient’s own blood, UCART19 cells come from healthy donors.

This overcomes the problem of many leukaemia patients not having enough healthy T-cells — a type of white blood cell that fights off disease — to be harvested after chemotherapy.

A further possible advantage is that donor cells can be mass produced for use in any patient, making them potentially more affordable than rival treatments that must be personalised for each individual. High costs are viewed as one of the biggest drawbacks of the so-called CAR-T therapies under development by Novartis, Juno and Kite.

Matt Kaiser, head of research at Bloodwise, a blood cancer charity, said the possibility of UCART19 cells providing an “off-the-shelf” treatment could be an important advance but cautioned that larger clinical trials were needed to prove it was safe and works.

“The concept of training immune cells to specifically recognise and hunt out leukaemia cells is very exciting and in theory could provide a lifetime cure for these children,” he said.

The promising signs for UCART19 is good news for Servier, the larger French drugmaker that has rights to commercialise the product, and for Pfizer, which has a partnership with Cellectis on similar experimental therapies.


Henry Sapiecha

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