A teenage girl's incurable cancer has been cleared from her body in the first use of a revolutionary new type of medicine.
...The team at Great Ormond Street used a technology called base editing, which was invented only six years ago.
...The large team of doctors and scientists used this tool to engineer a new type of T-cell that was capable of hunting down and killing Alyssa's cancerous T-cells.
They started with healthy T-cells that came from a donor and set about modifying them.
The first base edit disabled the T-cells targeting mechanism so they would not assault Alyssa's body
The second removed a chemical marking, called CD7, which is on all T-cells
The third edit was an invisibility cloak that prevented the cells being killed by a chemotherapy drug
...Most children with a leukaemia respond to the main treatments, but it is thought that up to a dozen a year could benefit from this therapy.
Alyssa is just the first of 10 people to be given the drug as part of a clinical trial.
Dr Robert Chiesa, from the bone-marrow transplant department at Great Ormond Street Hospital, said: "It is extremely exciting. Obviously, this is a new field in medicine and it's fascinating that we can redirect the immune system to fight cancer."