[Editorial] Gene-editing therapies: delivering safely for patients

“The pain I would feel in my body was like being struck by lightning and hit by a freight train all at once.” Victoria Gray's words will resonate with anyone who has experienced a sickle-cell disease crisis. In 2019, she became the first patient to have sickle-cell disease treated with the pioneering gene-editing therapy now known as Casgevy/exa-cel, which has since been approved for sickle-cell disease and β-thalassaemia. Her medical transformation was remarkable: “Now I can dream again without limitations.” Further successes have followed, including editing T cells as a leukaemia therapy and editing liver cells to treat transthyretin amyloidosis or metabolic conditions.