Gene editing has been used for the first time to successfully treat a human patient – a baby girl with leukaemia – after conventional treatments failed.
Re-writing genes is no longer science fiction thanks to gene-editing technologies called CRISPR and TALENs. Scientists can now alter any gene in any animal and have been using these techniques to cure genetic diseases like cystic fibrosis and muscular dystrophy in animal models. This year, Chinese scientists even edited genes in human embryos in a very controversial study.
All these studies are very exciting but they also highlighted some problems with the gene editing technologies. They appear to be less efficient in human cells than in animal cells and can cause unintended mutations in other genes. So this means that this type of treatment is not yet accurate enough to use in humans.
Unless it’s your last chance. Doctors in London were given special permission to trial genetically engineered T cells in Layla Richards because conventional treatments could not cure her leukaemia. Layla didn’t have enough healthy T cells of her own, so the scientists used ‘off-the-shelf’ T-cells called UCART19 cells.
UCART19 cells are made by editing T cells from a healthy donor so they recognise and attack cancer cells but leave healthy cells alone. The cells are also altered so that they cannot be cleared by the drug Alemtuzumab which is often used to treat leukaemia. The UCART19 cells also cannot be targeted by the immune system, so they do not cause graft versus host disease, one of the most severe side effects of transplants.
UCART19 cells can be made in batches so this is a cheaper treatment option that editing a patient’s own T cells. It can also be used in patients, like Layla, who do not have enough healthy T cells to harvest.
Several months after Layla was treated with 1ml of UCART19 cells she is still in remission.
Biotech company Cellectis is now collaborating with Pfizer and Servier to conduct a full trial of these cells in humans collaboration.
The Scientific Data: