New medical treatments will use genetic scissors, and other clever tricks

By Natasha Loder

New medicines to treat sickle-cell disease and beta thalassaemia, two genetic blood disorders, will make headlines in 2024. Most notable of these is the first CRISPR-gene-edited drug, which made its historic arrival in late 2023. Gene editing uses molecular scissors to edit DNA. It is a more precise form of modification than gene therapy, an older technology that uses a viral vector to inject a working gene into a cell. Gene editing has moved astonishingly quickly through drug pipelines—much faster than gene therapies, which have been slow and difficult to develop.

For sickle-cell disease, the gene-edited therapy, exa-cel, developed by Crispr Therapeutics and Vertex, is likely to be approved just ahead of a gene-therapy drug from Bluebird Bio, lovo-cel. In both cases, stem cells are first extracted from a patient’s body. They are then either edited (exa-cel) or transfected with the viral vector (lovo-cel), and returned to the body, where they correct the genetic defect. The effects are said to last a lifetime.