A Phase 1/2, Dose-Exploration Study to Evaluate the Safety and Efficacy of BEAM-301 in Patients With Glycogen Storage Disease Type Ia (GSDIa)

A Phase 1/2, Dose-Exploration Study to Evaluate the Safety and Efficacy of BEAM-301 in Patients With Glycogen Storage Disease Type Ia (GSDIa) Homozygous or Compound Heterozygous for the G6PC1 c.247C>T (p.R83C) Variant

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.

Study Overview

• Status: Recruiting
• Conditions: Glycogen Storage Disease Type Ia
• Intervention / Treatment: Drug: BEAM-301: Single dose of BEAM-301 administered by IV

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: Medical Information; Phone Number: 857-327-8641; Email: clinicalinfo@beamtx.com

Study Locations

• United States
  • California
    • Orange, California, United States, 92868
      • Recruiting
      • Clinical Study Site
  • Connecticut
    • Farmington, Connecticut, United States, 06030
      • Recruiting
      • Clinical Study Site
  • Texas
    • Houston, Texas, United States, 77030
      • Recruiting
      • Clinical Study Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Males or females age ≥18 years of age at the time of consent.
2. Diagnosis of GSDIa and homozygous or compound heterozygous for the G6PC1 c.247C>T (p.R83C) variant (confirmed by genetic testing).
3. History of at least 1 episode of hypoglycemia <60 mg/dL within the 2 years prior to signing the ICF.

Exclusion Criteria:

1. Liver transplant recipient/on waiting list for liver transplant or known history of liver cirrhosis.
2. 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.
3. Presence of liver adenoma >3 cm and ≤5 cm with a documented annual growth rate of ≥0.5 cm per year.
4. Have aspartate transaminase or alanine transaminase >upper limit of normal (ULN).
5. Total bilirubin levels >ULN; if documented Gilbert's Syndrome, total bilirubin >2 × ULN.
6. Previous treatment with any cell-, gene-, or viral vector-derived therapy Hospitalization for management of hypoglycemia within 4 weeks prior to signing the ICF.
7. Have triglycerides >1000 mg/dL or a history of pancreatitis or a history of acute pancreatitis within 5 years that does not have a known and corrected etiology (eg, cholecystectomy for gallstone pancreatitis).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: BEAM-301; BEAM-301 consists of adenine base editor messenger ribonucleic acid (mRNA) and single guide ribonucleic acid (gRNA) formulated in lipid nanoparticles (LNPs) for intravenous (IV) administration.	Drug: BEAM-301: Single dose of BEAM-301 administered by IV; BEAM-301 is designed to correct the G6PC1 c.247C>T allele via an A:T-to-G:C base-pair substitution, resulting in restoration of G6Pase-α catalytic activity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
To evaluate the safety and tolerability of BEAM-301 in patients with GSDIa with a G6PC1 c.247C>T (p.R83C) variant by measuring incidence of treatment-emergent adverse events (TEAEs) including serious adverse events (SAEs) and dose-limiting toxicities (DL	BEAM-301 administration through month 24

Secondary Outcome Measures

Outcome Measure	Time Frame
Absolute and change from baseline in time to hypoglycemia or metabolic decompensation during a controlled fasting challenge	Baseline to month 24
Changes from baseline in starch supplementation dose	Baseline to month 24
Level of serum glucose and metabolic parameters (lipid profile and uric acid) over time	Baseline to month 24
BEAM-301 PK parameters (Cmax)	Baseline to month 24
BEAM-301 PK parameters (AUC)	Baseline to month 24
BEAM-301 PK parameters (half-life)	Baseline to month 24

Collaborators and Investigators

• Sponsor: Beam Therapeutics Inc.

Study record dates

Study Major Dates

• Study Start (Actual): December 6, 2024
• Primary Completion (Estimated): December 30, 2027
• Study Completion (Estimated): December 30, 2027

Study Registration Dates

• First Submitted: December 6, 2024
• First Submitted That Met QC Criteria: December 11, 2024
• First Posted (Actual): December 16, 2024

Study Record Updates

• Last Update Posted (Actual): December 15, 2025
• Last Update Submitted That Met QC Criteria: December 9, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: GSD1a; GSDIa
• Additional Relevant MeSH Terms: Pathologic Processes; Metabolism, Inborn Errors; Genetic Diseases, Inborn; Carbohydrate Metabolism, Inborn Errors; Hepatorenal form of glycogen storage disease
• Other Study ID Numbers: BTX-301-001

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No