A 13-year-old has become leukaemia-free with help from a revolutionary new treatment, doctors say.

Alyssa, whose family did not want to give their surname, was diagnosed with T-cell acute lymphoblastic leukaemia in 2021.

Conventional treatments, including chemotherapy and a bone marrow transplant, failed to prevent the disease from returning.

In May, Alyssa was given universal CAR (chimeric antigen receptor) T-cells that had been pre-manufactured from a healthy donor, as part of a clinical trial.

Twenty-eight days later, she was in remission and was able to have a second bone marrow transplant.

She is said to be “doing well” recovering at home, while her condition is monitored by Great Ormond Street Hospital, where she received the treatment.

Alyssa’s mother Kiona said the family were “on a strange cloud nine”, adding: “Hopefully this can prove the research works and they can offer it to more children – all of this needs to have been for something.”

Alyssa, from Leicester, said: “Once I do it, people will know what they need to do, one way or another, so doing this will help people – of course I’m going to do it.”

Without the treatment, the next step was palliative care

The pre-manufactured cells were edited using new technology.

The edited CAR T-cells can then be given to a patient so that they quickly find and destroy T-cells in the body, including cancerous ones.

Then the person can have a bone marrow transplant to restore their depleted immune system.

Without the treatment, Alyssa’s only next step would have been palliative care, scientists said.

Dr Robert Chiesa, consultant in bone marrow transplant and CAR T-cell therapy at GOSH, said the outcome was “quite remarkable”, but said Alyssa’s condition must continue to be monitored over the next few months.

He said: “Since Alyssa got sick with her leukaemia in May last year, she never achieved a complete remission – not with chemotherapy and not after her first bone marrow transplant.

“Only after she received her CD7 CAR-T cell therapy and a second bone marrow transplant in GOSH she has become leukaemia-free.”

‘Ultimately better futures for sick children’

Professor Waseem Qasim, consultant immunologist at GOSH, said: “This is a great demonstration of how, with expert teams and infrastructure, we can link cutting-edge technologies in the lab with real results in the hospital for patients.

“It’s our most sophisticated cell engineering so far and paves the way for other new treatments and ultimately better futures for sick children.”

The research will be presented at the American Society of Haematology’s annual meeting in New Orleans this weekend.

Great Ormond Street Hospital wants to recruit up to 10 patients with T-cell leukaemia who have exhausted all conventional options for a clinical trial. They will be referred by specialists.