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Patients with a previously untreatable form of blood cancer are now living disease-free after a world-first gene therapy.
Alyssa Tapley, 16, became the first patient with an aggressive form of leukaemia to have the experimental treatment in 2022. She was considering options for palliative care, but is now healthy.
New results have been published of a clinical trial on a further eight children and two adults at Great Ormond Street Hospital (GOSH) and King’s College Hospital in London.
Two-thirds have been disease-free for up to three years.
Dr Deborah Yallop, consultant haematologist at King’s, said: “We’ve seen impressive responses in clearing leukaemia that seemed incurable – it’s a very powerful approach.”
The patients in the study had T-cell acute lymphoblastic leukaemia, a rare form of blood cancer that results from T-cells in the immune system growing out of control.
They had all failed to respond to existing treatment.
So the medical team tried an experimental technique to turn T-cells taken from a donor into fighting machines that beat the cancer.
The technique, called BE-CAR7, is a highly precise tool for changing individual letters in the genetic code, the instruction manual for all cells in the body.
Changing just one letter – what scientists call DNA “bases” – can alter the function of a gene in much the same way as substituting a single key letter in a text message can change its meaning.
The scientists made three individual “base-edits” to the donor T-cells.
The DNA tweaks made the cells an “off-the-shelf” treatment that didn’t need to be matched to patients like other transplants. And they also instructed the donor T-cells to destroy every one of a patient’s own T-cells – whether they were cancerous or not.
If all the T-cells were eradicated within four weeks of treatment, patients were able to go on and have a bone-marrow transplant to rebuild a healthy immune system.
Alyssa ‘doing…
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