Prime Medicine announces NEJM publication of PM359 data

Prime Medicine (PRME) announced the publication of Phase 1/2 clinical data with PM359, the Company’s investigational autologous hematopoietic stem cell product for p47phox chronic granulomatous disease, CGD, in the New England Journal of Medicine, NEJM. The data will also be presented in a poster session at the 67th American Society of Hematology, ASH, Annual Meeting, December 6-9, 2025 in Orlando, Florida. The publication, titled “Prime Editing for p47-phox Chronic Granulomatous Disease,” reports initial data for two patients treated in the Phase 1/2 trial of PM359, which was designed to assess safety, biological activity and preliminary efficacy in adult and pediatric study participants. Results: Both patients enrolled in the study had a history of prior CGD-defining complications; Both patients experienced rapid neutrophil engraftment, achieving 69% and 83% dihydrorhodamine-positive neutrophils by Day 30; Both patients remain free of new CGD-related complications or significant intercurrent illnesses post-infusion; No clinically significant adverse events attributable to PM359 occurred in either patient, and all observed toxicities were consistent with busulfan-based conditioning.