This is a Phase 1/2, multicenter, open-label, single-ascending-dose study to evaluate the safety, tolerability, and efficacy of BEAM-301 in adult patients with GSDIa homozygous or compound heterozygous for the G6PC1 c.247C\>T (p.R83C) variant and to determine the optimal biological dose.
Males or females age ≥18 years of age at the time of consent.
Diagnosis of GSDIa and homozygous or compound heterozygous for the G6PC1 c.247C>T (p.R83C) variant (confirmed by genetic testing).
History of at least 1 episode of hypoglycemia <60 mg/dL within the 2 years prior to signing the ICF.
Liver transplant recipient/on waiting list for liver transplant or known history of liver cirrhosis.
Presence of liver adenoma >5 cm in size based on liver MRI or liver ultrasound performed at screening or within 6 months prior to screening.
Presence of liver adenoma >3 cm and ≤5 cm with a documented annual growth rate of ≥0.5 cm per year.
Have aspartate transaminase or alanine transaminase >upper limit of normal (ULN).