Glycogen Storage Disease Type IANCT03970278
Study of Long-Term Safety and Efficacy on Gene Therapy in Glycogen Storage Disease Type Ia
An observational study of Glycogen Storage Disease Type IA and Von Gierke's Disease (GSD Type Ia), run by Ultragenyx Pharmaceutical Inc at 6 sites in 4 countries.
Trial summary
The primary objective of this study is to determine the long-term safety of DTX401 following a single intravenous (IV) dose in adults with GSDIa. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Glycogen Storage Disease Type IA, Von Gierke's Disease (GSD Type Ia)
- Type of treatment
- Injection or infusion
- How many people
- 12 participants
- Where
- 6 sitesin 4 countries
- Study dates
- 15 Jul 2019to 25 Feb 2025
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Subjects 18 years of age or older with GSDIa previously enrolled in 401GSDIA01.
Who may be able to join
- Received DTX401 in study 401GSDIA01.
- Willing and able to provide written informed consent after the nature of the study has been explained, and prior to any research-related procedures being performed.
- Willing and able to comply with all scheduled study visits, procedures, and requirements.
Who cannot join
- Planned or current participation in any other interventional clinical study that may confound the safety or efficacy evaluation of DTX401 during this study.
- Presence or history of any condition that, in the view of the Investigator, poses a risk to subject safety or places the subject at high risk of poor compliance or not completing the study or that would significantly affect the interpretation of study results.
Trial locations and contacts
6 sites in 4 countries.
6 sites in 4 countries
United States3 sites
Michigan Medicine University of Michigan
Ann Arbor, Michigan, 48109
UCONN Health
Farmington, Connecticut, 06030-3213
University of Texas Health Science Center at Houston
Houston, Texas, 77030
Canada1 site
Montreal Children Hospital, McGill University Health Centre
Montreal, Quebec, H4A3J1
Spain1 site
Complejo Hospitalario Universitario de Santiago
Santiago de Compostela, A Coruna, 15706
About this study
Official title: A Long-Term Follow-up Study to Evaluate the Safety and Efficacy of Adeno Associated Virus (AAV) Serotype 8 (AAV8)-Mediated Gene Transfer of Glucose-6-Phosphatase (G6Pase) in Adults With Glycogen Storage Disease Type Ia (GSDIa)
The primary objective of this study is to determine the long-term safety of DTX401 following a single intravenous (IV) dose in adults with GSDIa.
Read the detailed description
Only participants who received DTX401 in study 401GSDIA01 (NCT03517085) are eligible to participate in study 401GSDIA02. No investigational product will be administered during study 401GSDIA02. Participants will be followed in study 401GSDIA02 for at least 4 years, and up to 6 years after administration of DTX401.
- Being tested
- No intervention
- Keywords
- AAV, gene therapy, glucose metabolism disorder, carbohydrate metabolism, inborn errors, genetic diseases, Inborn Metabolic Diseases
- Medical subject headings
- Hepatorenal form of glycogen storage disease, Glycogen Storage Disease Type I, Glucose Metabolism Disorders, Carbohydrate Metabolism, Inborn Errors, Genetic Diseases, Inborn
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No interventionOther
No intervention
| Study group | Role | What they receive |
|---|---|---|
| DTX401 Cohort 1 | Participants received a single intravenous (IV) dose of 2.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with a reactive steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. Receives: Other: No intervention | |
| DTX401 Cohort 2 | Participants received a single IV dose of 6.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with a reactive steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. Receives: Other: No intervention | |
| DTX401 Cohort 3 | Participants received a single IV dose of 6.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with an optimized reactive steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. Receives: Other: No intervention | |
| DTX401 Cohort 4 | Participants received a single IV dose of 6.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with a prophylactic steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. Receives: Other: No intervention |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and Discontinuations Due to TEAEs
An adverse event (AE) is defined as any untoward medical occurrence, regardless of its causal relationship to study product. A TEAE is defined as any AE not present prior to the initiation of the drug treatment or any AE already present that worsens in either intensity or frequency following exposure to the drug treatment. A serious TEAE is an AE that meets any of the following criteria in the view of either the Investigator or Ultragenyx: death; life-threatening; inpatient hospitalization or prolongation of existing hospitalization; disability/Incapacity; congenital anomaly/birth defect not present at screening; other important medical events. Severity of events were graded as mild (grade 1), moderate (grade 2), severe (grade 3), life-threatening (grade 4), or death (grade 5). As DTX401 was administered as part of Study 401GSDIA01, all AEs in Study 401GSDIA02 were considered TEAEs.
Measured: From Baseline (Week 52 of 401GSDIA01/Visit 1 of 401GSDIA02) Up to Week 329
Secondary outcomes (1)
Change From Baseline in Time to First Hypoglycemic Event During a Controlled Fasting Challenge Over Time
The change from baseline in time (in hours) to first hypoglycemic event (defined as glucose < 54 mg/dL [< 3.0 mmol/L]) during a controlled fasting challenge at the participant's last visit. A positive change from baseline is favorable. Change from baseline is calculated from Baseline (Week 0) of the 401GSDIA01 study.
Measured: Baseline (Week 0 of 401GSDIA01), Weeks 52 (Visit 1 of 401GSDIA02), 78, 104, 130, 156, 182, 208, 234, 260, Last Visit (Up to Week 329)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 May 2019
- Study start15 Jul 2019
- Primary completion25 Feb 2025
- Study completion25 Feb 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Glycogen Storage Disease Type IAStudies of the same condition, open and under way.
- More trials run by Ultragenyx Pharmaceutical IncThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- Ultragenyx Pharmaceutical Inc
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Ultragenyx Pharmaceutical Inc
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03970278
- Sponsor's protocol ID
- 401GSDIA02
- Other IDs
- 2018-004473-27, 2023-504004-29-00, 2023, 2018
- Status last verified
- Mar 2026
- First submitted
- 29 May 2019
- Last updated
- 18 Mar 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- Individual data sharing
- No: Due to the rarity of GSDIa and the small number of subjects in this trial, individual patient data will not be shared in order to safeguard patient privacy, consistent with the data sharing commitment statement listed on Ultragenyx.com.
Study at a glance
From the registry record, last updated by the sponsor on 18 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Long-Term Follow-up Study to Evaluate the Safety and Efficacy of Adeno Associated Virus (AAV) Serotype 8 (AAV8)-Mediated Gene Transfer of Glucose-6-Phosphatase (G6Pase) in Adults With Glycogen Storage Disease Type Ia (GSDIa)
- ClinicalTrials.gov ID
- NCT03970278
- Acronym / sponsor ID
- 401GSDIA02
- Keywords
- AAV, gene therapy, glucose metabolism disorder, carbohydrate metabolism, inborn errors, genetic diseases, Inborn Metabolic Diseases
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- Ultragenyx Pharmaceutical IncIndustry (pharma, biotech, devices)
- Study start
- 15 Jul 2019 (actual)
- Primary completion
- 25 Feb 2025 (actual)
- Study completion
- 25 Feb 2025 (actual)
- First posted
- 31 May 2019 (actual)
- Results
- Posted 18 Mar 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary objective of this study is to determine the long-term safety of DTX401 following a single intravenous (IV) dose in adults with GSDIa.
Detailed description
Only participants who received DTX401 in study 401GSDIA01 (NCT03517085) are eligible to participate in study 401GSDIA02. No investigational product will be administered during study 401GSDIA02. Participants will be followed in study 401GSDIA02 for at least 4 years, and up to 6 years after administration of DTX401.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| DTX401 Cohort 1 | – | Other: No interventionParticipants received a single intravenous (IV) dose of 2.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with a reactive steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. |
| DTX401 Cohort 2 | – | Other: No interventionParticipants received a single IV dose of 6.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with a reactive steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. |
| DTX401 Cohort 3 | – | Other: No interventionParticipants received a single IV dose of 6.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with an optimized reactive steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. |
| DTX401 Cohort 4 | – | Other: No interventionParticipants received a single IV dose of 6.0 × 10^12 GC/kg DTX401(pariglasgene brecaparvovec) with a prophylactic steroid regimen during their participation in study 401GSDIA01 (NCT03517085). No intervention was provided during the 401GSDIA02 long term follow up study. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Subjects 18 years of age or older with GSDIa previously enrolled in 401GSDIA01.
Key inclusion criteria (3 listed)
- Received DTX401 in study 401GSDIA01.
- Willing and able to provide written informed consent after the nature of the study has been explained, and prior to any research-related procedures being performed.
- Willing and able to comply with all scheduled study visits, procedures, and requirements.
Key exclusion criteria (2 listed)
- Planned or current participation in any other interventional clinical study that may confound the safety or efficacy evaluation of DTX401 during this study.
- Presence or history of any condition that, in the view of the Investigator, poses a risk to subject safety or places the subject at high risk of poor compliance or not completing the study or that would significantly affect the interpretation of study results.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No interventionNo intervention | Other | DTX401 Cohort 1, DTX401 Cohort 2, DTX401 Cohort 3, DTX401 Cohort 4 |
Primary outcome
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and Discontinuations Due to TEAEs
Time frame: From Baseline (Week 52 of 401GSDIA01/Visit 1 of 401GSDIA02) Up to Week 329
An adverse event (AE) is defined as any untoward medical occurrence, regardless of its causal relationship to study product. A TEAE is defined as any AE not present prior to the initiation of the drug treatment or any AE already present that worsens in either intensity or frequency following exposure to the drug treatment. A serious TEAE is an AE that meets any of the following criteria in the view of either the Investigator or Ultragenyx: death; life-threatening; inpatient hospitalization or prolongation of existing hospitalization; disability/Incapacity; congenital anomaly/birth defect not present at screening; other important medical events. Severity of events were graded as mild (grade 1), moderate (grade 2), severe (grade 3), life-threatening (grade 4), or death (grade 5). As DTX401 was administered as part of Study 401GSDIA01, all AEs in Study 401GSDIA02 were considered TEAEs.
1 secondary outcome
Change From Baseline in Time to First Hypoglycemic Event During a Controlled Fasting Challenge Over Time
Time frame: Baseline (Week 0 of 401GSDIA01), Weeks 52 (Visit 1 of 401GSDIA02), 78, 104, 130, 156, 182, 208, 234, 260, Last Visit (Up to Week 329)
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Mar 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Ultragenyx Transparency CommitmentLink provided by the sponsor.
- Individual participant dataSharing planned: No. Due to the rarity of GSDIa and the small number of subjects in this trial, individual patient data will not be shared in order to safeguard patient privacy, consistent with the data sharing commitment statement listed on Ultragenyx.com.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Medical Director study director
Ultragenyx Pharmaceutical Inc
6 sites in 4 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Glycogen Storage Disease Type IA and Von Gierke's Disease (GSD Type Ia), run by Ultragenyx Pharmaceutical Inc at 6 sites in 4 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in United States, Canada, Netherlands, Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 18 Mar 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and Discontinuations Due to TEAEs (time frame: From Baseline (Week 52 of 401GSDIA01/Visit 1 of 401GSDIA02) Up to Week 329). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Mar 2026.