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Basic editing, the therapy that cleared the 13-year-old's incurable cancer

Basic editing, the therapy that cleared the 13-year-old's incurable cancer

A teenager's incurable cancer has been cleared from her body in the first use of a new therapy called core editing.

All previous treatments for Alyssa had failed. So doctors at Great Ormond Street Hospital in Leicester used "basic editing".

Six months later, the cancer is gone, but Alyssa is still being monitored in case it returns.

Basic editing, the therapy that cleared the 13-year-old's incurable cancer

Alyssa, who is 13, was diagnosed with T-cell acute lymphoblastic leukemia in May last year. T cells are supposed to be the guardians of the body but for Alyssa they had become dangerous and were growing out of control.

Her cancer was aggressive. Chemotherapy and then a bone marrow transplant were unable to rid her body of it.

Basic editing, the therapy that cleared the 13-year-old's incurable cancer

"Eventually I would have died," Alyssa said.

The team at Great Ormond Street used a technology called core editing, which was invented just six years ago.

The bases are the language of life containing the four basic types: - adenine (A), cytosine (C), guanine (G) and thymine (T) - building blocks of our genetic code.

Basic editing, the therapy that cleared the 13-year-old's incurable cancer

Base editing allows scientists to amplify a precise part of the genetic code and then change the molecular structure of a single base, turning it into another and changing the genetic instructions.

The large team of doctors and scientists used this tool to create a new type of T cells that were able to hunt down and kill Alyssa's cancerous T cells.

Basic editing, the therapy that cleared the 13-year-old's incurable cancer

They started with healthy T cells that came from a donor and began to modify them.

Basic editing, the therapy that cleared the 13-year-old's incurable cancer

"She is the first patient to be treated with this technology," said Prof Waseem Qasim, from UCL and Great Ormond Street.