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.
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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 really well’
According to results published in the New England Journal of Medicine, 82% of the patients in the trial were in “very deep remission” after treatment and were able to have a transplant.
And 64% remain disease-free.
Alyssa said she was now “doing really well”.
“I’ve gone sailing, spent time away from home doing my Duke of Edinburgh Award but even just going to school is something I dreamed of when I was ill,” she said.
“I’m not taking anything for granted.
“Next on my list is learning to drive, but my ultimate goal is to become a research scientist and be part of the next big discovery that can help people like me.”
Hospital charity agrees to support treatment of 10 more patients
The Great Ormond Street Hospital Charity has now agreed to support treatment for another 10 patients.
Dr Rob Chiesa, study investigator and bone marrow transplant consultant at GOSH, said: “Although most children with T-cell leukaemia will respond well to standard treatments, around 20% may not.
“It’s these patients who desperately need better options and this research provides hope for a better prognosis for everyone diagnosed with this rare but aggressive form of blood cancer.”
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Results ‘bring hope’
UK stem cell charity Anthony Nolan worked with the research team to provide T-cell donors.
Dr Tania Dexter, senior medical officer at the charity, said: “Considering these patients had a low chance of survival before the trial, these results bring hope that treatments like this will continue to advance and become available to more patients.
“As with any novel cellular therapy, this phase 1 trial is just an initial indication of the effectiveness and safety of the treatment, and more work must be done to determine its wider clinical application.
“Yet the results are encouraging and demonstrate the recent leaps in technology that are allowing us to take on even greater challenges in the treatment of blood cancers and blood disorders.”
