Simple explanation
White blood cells swallow bacteria and then produce a burst of reactive chemicals to destroy them. In chronic granulomatous disease the machinery that makes that burst is broken, so the cells can catch germs but not kill them, leading to repeated severe infections. In 2025 this became the first disease treated with prime editing: a patient's own blood stem cells were corrected outside the body and returned.
Go deeper
CGD results from defects in NADPH oxidase subunits; the autosomal recessive p47phox form is most often caused by a GT dinucleotide deletion in NCF1. PM359 corrects that deletion by prime editing in autologous CD34+ haematopoietic stem cells, which are reinfused after busulfan conditioning. Published results in the first participants reported prompt neutrophil and platelet engraftment, 69 per cent and 83 per cent dihydrorhodamine-positive neutrophils by day 30, durable restoration of NADPH oxidase activity, and early clinical benefit including resolution of CGD-associated colitis.
What this establishes
That prime editing works clinically. Until this result, prime editing's clinical case rested on laboratory capability and theoretical breadth. Two patients with restored immune function and early clinical improvement is a small dataset, and it is a categorically different kind of evidence from anything that preceded it.
It should be read for what it is: a first-in-human report in a very small number of participants with short follow-up, published in a major journal precisely because the finding is a first.
Sources
- New England Journal of Medicine · 2025
Prime Editing for p47phox-Deficient Chronic Granulomatous Disease ↗ - ClinicalTrials.gov
A study of the safety and efficacy of prime editing (PM359) in participants with p47phox autosomal recessive CGD ↗