Teenager diagnosed with leukaemia at 13 makes history with pioneering cancer treatment

Alyssa's diagnosis came in May 2021 after months of symptoms her family had mistaken for ordinary colds and tiredness.

But neither chemotherapy nor a bone marrow transplant worked for her, leaving the young patient believing her cancer couldn't be beaten.

But three years on from receiving the groundbreaking therapy at Great Ormond Street Hospital in 2022, Alyssa is now 16 and completely cancer-free. She's been discharged to long-term follow-up care.

Her decision to join the trial came from a place of selflessness, driven by a desire to help others.

"I chose to take part in the research as I felt that, even if it didn't work for me, it could help others," she said. "Years later, we know it worked, and I'm doing really well. I've done all those things that you're supposed to do when you're a teenager."

She's been sailing, completed time away from home for her Duke of Edinburgh Award, and even returned to school – something she could only dream about during her illness.

"I'm not taking anything for granted," Alyssa added. "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."

How does the treatment work?

Traditional CAR T-cell therapy takes a patient's own T cells, modifies them in a laboratory with special proteins called chimeric antigen receptors, then infuses them back into the bloodstream to hunt down cancer.

But there's a catch when treating T-cell leukaemia – the cancer itself develops from abnormal T cells, making the standard approach far trickier.

BE-CAR7 gets around this problem by using healthy donor T cells instead.

Scientists at Great Ormond Street Hospital and University College London developed a technique called base editing, which allows them to alter individual letters of DNA code within living cells.

This clever modification lets the T cells function after chemotherapy while preventing them from attacking the patient's normal cells.

Once the base-edited CAR T-cells enter a patient's body, they quickly seek out and destroy all T cells, including the cancerous ones.

If the leukaemia clears within four weeks, doctors then rebuild the immune system through a bone marrow transplant over several months.

The clinical trial results are genuinely impressive – 64 per cent of the 13 patients treated with BE-CAR7 are now disease-free, with findings published in the New England Journal of Medicine.

Professor Waseem Qasim, a cell and gene therapy expert at UCL, said: "We've shown that universal or 'off-the-shelf' base-edited CAR T-cells can seek and destroy very resistant cases of CD7+ leukaemia."