Prime Medicine reports first clinical prime-editing data: PM359 restores neutrophil function in a CGD patient

Prime Medicine/PM359 (CGD)

In the first patient treated with PM359, blood stem cells corrected by prime editing outside the body restored NADPH oxidase activity (DHR positivity) in 58% of neutrophils by day 15 and 66% by day 30, well above the roughly 20% threshold thought necessary for clinical benefit. This was the first clinical data for prime editing.

• Patient 1: DHR-positive neutrophils rose to 58% by day 15, 66% by day 30.
• Threshold for clinical benefit estimated at ~20% DHR-positive cells.
• Prime editing corrects the disease-causing p47phox gene mutation ex vivo in blood stem cells.
• First human clinical data demonstrating prime editing technology.