A Study of Adeno-Associated Virus Serotype 8-Mediated Gene Transfer of Glucose-6-Phosphatase in Patients With Glycogen Storage Disease Type Ia (GSDIa)
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ClinicalTrials.gov Identifier: NCT05139316 |
Recruitment Status :
Recruiting
First Posted : December 1, 2021
Last Update Posted : June 10, 2022
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Glycogen Storage Disease Type IA | Genetic: DTX401 Other: Placebo Drug: Oral corticosteroids Drug: Placebo for oral corticosteroids | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 50 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study of Adeno-Associated Virus Serotype 8-Mediated Gene Transfer of Glucose-6-Phosphatase in Patients With Glycogen Storage Disease Type Ia |
Actual Study Start Date : | November 8, 2021 |
Estimated Primary Completion Date : | April 2023 |
Estimated Study Completion Date : | April 2024 |

Arm | Intervention/treatment |
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Experimental: DTX401, Then Placebo
Participants receive single peripheral intravenous (IV) infusion of DTX401 in solution. At week 48 participants receive single peripheral IV infusion of Placebo.
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Genetic: DTX401
nonreplicating, recombinant, adeno-associated virus (AAV) serotype 8 (AAV8) Other: Placebo Normal Saline infusion Drug: Oral corticosteroids Participants who receive DTX401 solution will receive oral corticosteroids
Other Name: prednisolone Drug: Placebo for oral corticosteroids Participants who receive Placebo will receive placebo oral corticosteroids to maintain the study blind |
Placebo Comparator: Placebo, Then DTX401
Participants receive single peripheral IV infusion of Placebo. At week 48 eligible participants receive single peripheral IV infusion of DTX401 solution.
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Genetic: DTX401
nonreplicating, recombinant, adeno-associated virus (AAV) serotype 8 (AAV8) Other: Placebo Normal Saline infusion Drug: Oral corticosteroids Participants who receive DTX401 solution will receive oral corticosteroids
Other Name: prednisolone Drug: Placebo for oral corticosteroids Participants who receive Placebo will receive placebo oral corticosteroids to maintain the study blind |
- Percent Change from Baseline to Week 48 in Daily Cornstarch Intake [ Time Frame: Baseline, Week 48 ]
- Change from Baseline to Week 48 in the Percentage of Time Spent in Normal Glucose Control (60 to 120 mg/dL [3.3 to 6.7 mmol/L]) as Measured by Continuous Glucose Monitoring (CGM) for Noninferiority [ Time Frame: Baseline, Week 48 ]
- Change from Baseline to Week 48 in Time to Hypoglycemia (< 54 mg/dL [< 3.0 mmol/L]) During a Controlled Fasting Challenge [ Time Frame: Baseline, Week 48 ]
- Change from Baseline to Week 48 in Percentage of Time Spent in Normal Glucose Control (60 to 120 mg/dL [3.3 to 6.7 mmol/L]) as Measured by CGM for Superiority [ Time Frame: Baseline, Week 48 ]
- Change from Baseline to Week 48 in Number of Total Daily Doses of Cornstarch [ Time Frame: Baseline, Week 48 ]
- Change from Baseline to Week 48 in the Glycogen Storage Disease Functional Assessment Diary (GSD FAD) Signs and Symptoms Scale [ Time Frame: Baseline, Week 48 ]
- Number of Treatment Emergent Adverse Events (TEAEs), TEAEs of Special Interest, Serious TEAEs, Related TEAEs, Discontinuations From Study or Investigational Product Due to Adverse Events (AEs), and Fatal AEs [ Time Frame: up to 96 weeks ]
- Number of Participants with Clinically Relevant Changes in Standard Chemistry [ Time Frame: up to 96 weeks ]
- Number of Participants with Clinically Relevant Changes in Hematology [ Time Frame: up to 96 weeks ]
- Number of Participants with Clinically Relevant Changes in Urinalysis [ Time Frame: up to 96 weeks ]
- Number of Participants with Clinically Relevant Changes in Physical Exams [ Time Frame: up to 96 weeks ]
- Number of Participants with Clinically Relevant Changes in Vital Signs [ Time Frame: up to 96 weeks ]

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Ages Eligible for Study: | 8 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Key Inclusion Criteria:
- Documented GSDIa with confirmation by molecular testing or enzymatic activity on liver biopsy
- Currently receiving a therapeutic regimen of cornstarch (or equivalent) and is clinically stable as evidenced by no more than a 10% change in cornstarch (or equivalent) regimen and no hospitalization for hypoglycemia over a 4 week period
- Willing and able to complete the informed consent process and to comply with study procedures and visit schedule
- Females of childbearing potential and fertile males must consent to use highly effective contraception from the period following informed consent through the duration of the 96-week study and in cases of early withdrawal at least 48 weeks after the last dose of investigational product (IP). Female subjects must agree not to become pregnant. Male subjects must agree not to father a child or donate sperm
Key Exclusion Criteria:
- Detectable pre-existing antibodies to the AAV8 capsid
- History of liver transplant, including hepatocyte cell therapy/ transplant
- History of liver disease
- Presence of liver adenoma >5 cm in size
- Presence of liver adenoma >3 cm and ≤5 cm in size that has a documented annual growth rate of ≥0.5 cm per year
- Significant hepatic inflammation or cirrhosis as evidenced by imaging or any of the following laboratory abnormalities: alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > upper limit of normal (ULN), total bilirubin >1.5 × ULN, alkaline phosphatase >2.5 × ULN
- Non-fasting triglycerides ≥1000 mg/dL
- Pregnant, breastfeeding, or planning to become pregnant (self or partner) at any time during the study.
- Current or previous participation in another gene transfer study
- History of illicit drug use within 60 days prior to screening or positive results from an 8-panel urine drug screen during the Screening Period completed at 2 time points at least 6 weeks apart
Note additional inclusion/exclusion criteria may apply, per protocol

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05139316
Contact: Patients Contact: Trial Recruitment | 1-888-756-8657 | TrialRecruitment@ultragenyx.com | |
Contact: HCPs Contact: Medical Information | 1-888-756-8657 | medinfo@ultragenyx.com |

Study Director: | Medical Director | Ultragenyx Pharmaceutical Inc |
Responsible Party: | Ultragenyx Pharmaceutical Inc |
ClinicalTrials.gov Identifier: | NCT05139316 |
Other Study ID Numbers: |
DTX401-CL301 2020-004184-12 ( EudraCT Number ) |
First Posted: | December 1, 2021 Key Record Dates |
Last Update Posted: | June 10, 2022 |
Last Verified: | June 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
glycogen storage disorder Ia AAV gene therapy von Gierke disease |
glucose metabolism disorder GSDIa GSD1 |
Glycogen Storage Disease Glycogen Storage Disease Type I Metabolic Diseases Carbohydrate Metabolism, Inborn Errors Metabolism, Inborn Errors Genetic Diseases, Inborn Prednisolone |
Anti-Inflammatory Agents Glucocorticoids Hormones Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs Antineoplastic Agents, Hormonal Antineoplastic Agents |