A paper recently published in Nature from David Liu and co-workers discloses a ‘prime’ gene-editing system many years in the making.
In principle, the system, comprising a catalytically impaired Cas9 enzyme and an engineered reverse transcriptase, may be able to address ~89% of the human genetic variants known to be pathogenic. Already, it has been snapped up as the key founding intellectual property for Cambridge, Massachusetts-based startup Prime Medicine. Another startup, Beam Therapeutics, has also moved to gain exclusive rights to use of the technology in editing single-base transition mutations, as well as for developing therapies for sickle-cell disease. In return, Prime Medicine has access to aspects of Beam’s CRISPR base-editing technology, including its Cas12b enzyme for use in mammalian systems, and to its delivery technology. Prime editing is still a nascent, albeit highly promising, technology. Demonstrating its feasibility in a wide range of cells and tissues will be key to its future development.