A therapy that would once have been considered a feat of science fiction has reversed aggressive and incurable blood cancers in some patients, doctors report.
The treatment involves precisely editing the DNA in white blood cells to transform them into a cancer-fighting “living drug”.
The first girl to be treated, whose story we reported in 2022, is still free of the disease and now plans to become a cancer scientist.
Now eight more children and two adults with T-cell acute lymphoblastic leukaemia have been treated, with almost two thirds (64%) of patients in remission.
T-cells are supposed to be the body’s guardians – seeking out and destroying threats – but in this form of leukaemia, they grow out of control.
For those on the trial, chemotherapy and bone marrow transplants had failed. Apart from the experimental medicine, the only option left was to make their death more comfortable.
“I really did think that I was going to die and I wouldn’t be able to grow up and do all the things that every child deserves to be able to do,” says 16-year-old Alyssa Tapley from Leicester.
She was the first person in the world to have the treatment at Great Ormond Street Hospital and is now enjoying life.The team at University College London (UCL) and Great Ormond Street Hospital used a technology called base editing.
Bases are the language of life. The four types of base – adenine (A), cytosine (C), guanine (G) and thymine (T) – are the building blocks of our genetic code. Just as letters in the alphabet spell out words that carry meaning, the billions of bases in our DNA spell out the instruction manual for our body.
Base editing allows scientists to zoom to a precise part of the genetic code and then alter the molecular structure of just one base, converting it from one type to another and rewriting the instruction manual.
Researchers wanted to harness the natural power of healthy T-cells to seek out and destroy threats and turn that against the T-cell acute lymphoblastic leukaemia.
This is a tricky feat. They had to engineer the good T-cells to hunt the bad ones without the treatment annihilating itself.
