In a major breakthrough for advanced therapies, researchers from University College London (UCL) and Great Ormond Street Hospital (GOSH) have reported positive outcomes from the world’s first clinical trial using base-edited CAR T-cell therapy. This next-generation treatment, known as BE-CAR7, was tested in children with relapsed or refractory T-cell acute lymphoblastic leukaemia (T-ALL)—a rare and aggressive blood cancer.

The therapy uses base editing, a refined form of CRISPR, to precisely change one DNA letter in donor T cells before adding a chimeric antigen receptor (CAR) that targets leukaemia cells. According to findings published in the New England Journal of Medicine, 82% of patients achieved deep remission, and 64% remain disease-free, with follow-ups extending beyond three years in some cases. Importantly, side effects were manageable, and the edited cells showed sustained anti-cancer activity.

Lead researcher Professor Waseem Qasim described the results as almost “science fiction,” noting that just a few years ago such a therapy would have been unimaginable. The trial offers a new line of hope for children who had run out of treatment options. BE-CAR7 was developed in the UK through public-private collaboration, and trial expansion is now underway across additional UK centres in 2026.

This pioneering use of base-edited immune cells highlights how genome editing is not only reshaping therapeutic possibilities, but also strengthening the UK’s leadership in personalised, cell-based cancer treatment.