A Study of the Safety and Efficacy of Prime Editing (PM359) in Participants With p47phox Autosomal Recessive Chronic Granulomatous Disease (CGD )

Inclusion Criteria:

• Autosomal recessive Chronic Granulomatous Disease due to the delGT mutation in NCF1causing dysfunction of p47phox

• Treated and followed for at least the past 2 years in a specialized center

• Willingness to participate in this study as well as a long-term follow-up study withthe understanding that the total participation is 15 years

• At least 1 prior severe CGD-related infection OR an ongoing severe CGD-relatedinfection requiring therapy or that is refractory to standard therapy; OR anautoimmune or inflammatory condition related to CGD that is active or requiringtherapy to maintain remission.

Exclusion Criteria:

• For participants younger than 16 years of age: known, willing, and available 10/10 (A,B,C,DR,DQ) HLA-matched related donor (10/10 MRD)

• Active bacteremia or fungemia

• Ongoing inflammatory condition that is ≥ CTCAE v5.0 Grade 3 despite high-dosesteroids (≥ 0.5 mg/kg/day of prednisone and/or equivalent).

• Any contraindication which in the opinion of the transplant physician would make theparticipant ineligible to undergo autologous HSCT, including, but not limited to:

1. Contraindication to mobilization and apheresis, including severe allergicreaction to receipt of any medication or other drug substance required formobilization and apheresis (e.g., G-CSF, plerixafor) or PM359 manufacture (e.g., DMSO).

2. Contraindication to receipt of the conditioning agent, busulfan.

• Positive for presence of human immunodeficiency virus (HIV)-1 or HIV-2, or activeinfection with hepatitis B virus (HBV), or hepatitis C virus (HCV).

• Inadequate organ function, including known chronic advanced end-organ damage whichin the opinion of the investigator would put the participant at risk for undergoingHSCT

• Prior or current malignancy or myeloproliferative disorder (excluding Stage 1 orlower, fully treated/excised malignant and pre-malignant disease of the skin, cervixor colon).

• Any other condition that, in the opinion of the Investigator, may compromise thesafety or compliance of the participant or would preclude the participant fromsuccessful study completion, including Participant/Parent/Guardian unable orunwilling to comply with the protocol requirements.

• Pregnancy or breastfeeding in a postpartum female or absence of adequatecontraception for fertile participants. Females of childbearing potential andnon-sterile male participants who are or may become sexually active with femalepartners of childbearing potential are required to use highly effectivecontraception from Screening through at least 12 months after drug product infusion.

• Participation in another clinical study with an investigational drug within 30 daysof Screening or at least 5 times the half-life of the investigational drug (whichever is longer), or any prior receipt of gene therapy or hematopoietic stemcell transplant.