In May 2022, 13-year-old Alyssa became the first reported patient in the world to receive base-edited T-cells at Great Ormond Street Hospital for Children to treat her "incurable" T-cell leukemia.
She was diagnosed in 2021 and despite receiving the standard available therapies for her cancer, including chemotherapy and a bone marrow transplant, her leukemia unfortunately returned.
As the first patient in a new clinical trial, Alyssa received genetically modified CAR T-cells that originally came from a healthy donor. Initially, however, all CAR-T treatments involved removing a person’s own T cells, editing them and replacing them in that patient. Using T-cells from someone else would lead to them attacking the recipient’s own body cells. Not only is this highly expensive but it usually is not feasible to obtain enough T-cells to create CAR-T cells from an extremely unwell patient.
The new approach, that was used to treat Alyssa, involves editing T-cells from a donor using a new base-editing technology, which allows the cells to recognize and kill the cancerous T-cells without attacking each other.
Just 28, days after receiving the dose of CAR-T cells, Alyssa was in remission and later received a second bone marrow transplant to restore her immune system. Other trials are underway, with the aim of developing more treatments that use base editing, so that more patients, like Alyssa, can be treated.
It’s safe to say we are yet to see the full potential of gene editing technology in the medical world.